Page 2 of 3 FirstFirst 123 LastLast
Results 36 to 70 of 96

Thread: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

  1. #36
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Lugalong, wishing I had a good research budget for carbon fiber birdwing production techniques doesn't make it so. I'm more of a laminated spruce kind of guy with carbon fiber tastes. The only good news there is that I automatically design for the poor average smuck because I am that guy. I would truly love to see a full race carbon fiber version of Muri-Maru with carbon fiber birdwing masts but the funds for that are not in my bank account. Rudderless would have me mortgage my house and charge onward with a top-notch build but I'd much rather be debt free. The other thing is as a retired guy, I finally have enough time on my hands to get in good physical shape and that priority has risen to the top in recent years. As a result I'm in better shape than I have been since my frisbee throwing days at FSU and that was over thirty years ago. I'm not willing to give that up by starting a business or spending too much time fussing with building a race boat. So it's a weird situation really.

    Lately I've been thinking the best way to promote birdwing research is to give the technology away for free anywhere outside the USA where the patent has no power anyway. If I could show the design successfully utilized in the UK, Sweden, or New Zealand for example, it would be a much easier sale here in the USA where the patent does have power and value. Until then, I'll keep plugging away with the resources I have and enjoy the ride as best I can. For sure, how much planing Muri-Maru does very much depends on how light, strong, and stiff she turns out. And it's a big difference too between her displacement hull speed and her speed on a plane. Fast or slow, however, I will enjoy the boat if she does the one thing I want most in my retirement and that is to successfully complete the Texas 200. By keeping my goals modest and simple it increases my chances of success. When you retire your priorities change. I enjoy going fast on my bicycle because all I have to do is pedal faster. If I have to mortgage my house to go faster on a boat, I'm not really very interested. Besides, if speed were the priority, I'd build a proa!

    But if it's art we are talking about, I can do that. Muri-Maru with spruce birdwing masts, tanbark sails, a bamboo sunshade and a Chinese-style rudder/ladder could be really something and if it could also successfully get me through the challenging Texas 200, that would be performance art worth telling about and showing.

    Skaraborgcraft, thanks for the heads up on the cup holders and the trouble with mirrors. Maybe gimbaled cup holders and cheap closed circuit TV's are in my future!
    Last edited by kenjamin; 07-25-2017 at 08:55 AM.

  2. #37
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Kenjamin, sure, it is easy to understand your situation where spending much for the sake of speed on the water is not the object. I was just trying hard to avoid being one of the detractors of your efforts with the birdwing rig, rather than meaning to encourage you to spend more than it might be worth.
    I am building a proa not because the theoretical speed potential is so attractive, but because rig and power costs can be reduced with this type of craft.
    I contemplate using carbon fibre in and on my own designs purely as a means to meet a compromise where weight can be reduced without busting the budget.
    For me to afford clear spruce and the space and tooling to laminate spars that need shaped by having a router swung over a giant arc would be way more costly than laying carbon (multiple tow lengths or uni strips) into bamboo shells or onto a mandrel before wetting out with epoxy......OK admittedly I do own a vacuum pump, which probably cost me only as much as your router. To this pump I will connect a plastic bag with some polytube and then there will be added costs of a few more consumables, but not at greatly increased costs.
    making the wooden birdwing spar as a male form/mould would be a bigger deal than getting resin infused into the synthetic fibres.....but you have already made the spar to start with.

    Expecting the spruce spar to be as light and stiff as the carbon reinforced one is not realistic, so I would be happy to compromise by making do with straight spars and going with a lug rig.
    The Chinese lug rig shown in graphics earlier on in this thread looks to be workable for doing 200 mile coastal passage…….. if speed is really not the object.
    A displacement rather than a planning hull is likewise an acceptable compromise re cost vs performance.
    Suggestions to use carbon composite skins on an EPS foam cored deck structure was prompted by your admission that an earlier Texas 200 event had been hampered by an over burdened boat and that the Yangtze Pelican is essentially a dinghy-like sailer rather than a hull intended to be sailed when loaded down on her lines.
    Being light, along with expectation for use as buoyant top hamper aiding capsize recovery, makes the low density foam sandwich cuddy a logical choice. But understandably, there is the perception that composites is all about performance, so that a more cruisey option in wood is fine as a compromise.
    Sure!, but carrying an extra mast to match the picture of the birdwing split rig is going to add cost and weight which the original design avoided, so I was thinking of somehow finding a balance to help find a place for the rig.
    Using composites does not necessarily add much to costs……for me, the use of composites has allowed fabrication of parts without the luxury of facilities which I would have needed if lumber had to be machined and laminated. Most of the time, bucket and brush with the help of a trimming knife while working under a tent was sufficient.
    If you have to have a free standing rotting mast, surely the material which provides the best result is all good, otherwise why not be open to alternative design options?.
    Cutting to the quick of it – you will save in cost and weight by going with a stayed rig and might then keep up with the rest of the fleet in the Texas 200.
    Still, I appreciate that someone chooses to create something out of the ordinary. It's just that I think(for justifiable reason) that a curved and free standing mast in wood is asking too much of the material.
    Last edited by Lugalong; 07-26-2017 at 12:53 AM.

  3. #38
    Join Date
    Jan 2010
    Location
    Sweden,Scilly Isles, Siberia
    Posts
    7,948

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by Lugalong View Post
    It's just that I think(for justifiable reason) that a curved and free standing mast in wood is asking too much of the material.
    I find that an odd remark as several rigs have already been built in wood. Would the spars be better for allround performance in carbon?, most likely. The hollow timber mast i built for the mariette pram weighs around 50kg, wall thickness was increased due to be a free standing mast in a tabernacle, and built in less than aircraft grade spruce. I was a bit shocked to find a bigger spar on an equal displacement boat in carbon, weighing 13kg! From the few videos i have seen, im not sure i want to attempt a carbon mast build, though i would most likely purchase one if the prices were more reasonable. Im not sure its as easy as wrapping a sheath around a PVC waterpipe, though i have seen that done with polyester and glass, tube stayed in and wood cores at stress points. I wondered if a thin wall box core with foam on the fore and aft faces for streamlining can have a carbon sheath over? Moulds and vacumn bagging seem like some wasted material for a noe-off, but i guess that depends on how badly you might want it. I did not delve too deeply into the subject due to lack of a temperture controlled enviroment, something that seems to be an important thing to do it right.

  4. #39
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by skaraborgcraft View Post
    I find that an odd remark as several rigs have already been built in wood. Would the spars be better for allround performance in carbon?, most likely. The hollow timber mast i built for the mariette pram weighs around 50kg, wall thickness was increased due to be a free standing mast in a tabernacle, and built in less than aircraft grade spruce. I was a bit shocked to find a bigger spar on an equal displacement boat in carbon, weighing 13kg! From the few videos i have seen, im not sure i want to attempt a carbon mast build, though i would most likely purchase one if the prices were more reasonable. Im not sure its as easy as wrapping a sheath around a PVC waterpipe, though i have seen that done with polyester and glass, tube stayed in and wood cores at stress points. I wondered if a thin wall box core with foam on the fore and aft faces for streamlining can have a carbon sheath over? Moulds and vacumn bagging seem like some wasted material for a noe-off, but i guess that depends on how badly you might want it. I did not delve too deeply into the subject due to lack of a temperture controlled enviroment, something that seems to be an important thing to do it right.

    As stated earlier in this thread, curvature in the spar allows a large amount of deflection at the masthead due to a small amount of twist. Torsional rigidity is the issue, so the stiffer the material the better. Carbon composite fits the bill in this case, because the curved and tapered shape can be easily turned into a form that stands convenient and ready to receive a draping of fibres. Over this a strip of polythene is placed and sealed up with tackytape…. Well, peel ply and breather fabric is included in the layup, but there’s no need to go into those details here.
    Poly pipes feed the resin in and help to pull the air out.Pots that can cope with atmospheric pressure can be made up with polyester and chopmat….covering most of the needed equipment.

    Since Ken is in Florida, there is not a problem with a thermoset resin.......as far as temperature goes.
    Right Ian! an oven would be called for up north and then you have a fire risk with makeshift ovens.

    It would be possible to make a straight hollow spar in a similar way, but then there is going to be a bit of metal fabrication required in the tooling, and also, there is no point in competing with production sport boat spar manufacturing…….working with the stuff is pretty much like mucking with coal dust.

    Ken already has the wooden spar shaped and ready to use, so a little work with resin/glass on a melamine laminating table will serve to get the tooling done, along with a few lengths of dowel.

    I’d have to draw diagrams of the whole set-up to explain it properly, which is the kind of thing I’d like to get around to once a system has been worked out regards how to quickly get images posted……Oh for the good old days when I could do a pen sketch on a sheet of A4 and send it through the scanner, then upload the file as Jpeg.

    Even if I could post diagrams of this particular design and method, I would agree with Ken that making a wooden spar is preferable.
    It’s going to be a hell of a lot more difficult in this case ( with a curved birdwing spar) to make a wooden outer shell into which carbon uni can be laid for stiffening. So if it has to be a birdwing shape, hollow and carbon isn’t half bad.
    Last edited by Lugalong; 07-26-2017 at 05:48 AM.

  5. #40
    Join Date
    Jan 2010
    Location
    Sweden,Scilly Isles, Siberia
    Posts
    7,948

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    ^ I agree with all of the above (i wont be building an oven). When it comes to deflection though, surely that can be an element that can be beneficial to anyone who is not a hard core racer? I recall a real competitive chap once waxing lyrical about the exceeding poor performance of a Freedom 40 ketch (free standing carbon masts), due to the issue of mast bend when hard on the wind in 25+knots; to him the loss of drive was speed over the water lost and possibly a race, to the Freedom owner it was a rig spilling wind and easing comfort. I might be wrong, but is there any point having such a stiff mast if it does not have an equally stiff hull below it either in hull form or via ballast? The weight issue i can really agree with, it helps with righting moment in a big way.
    I just sent a diagram i hand drew, via the scanner and attatched to an email as jpeg, have you upgraded to "new stuff", maybe that "cloud" thing....whatever that is?

  6. #41
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    I'm enjoying the discussion very much. It gives me insights into how other people see the birdwing mast and that is of great interest to me.

    The huge elephant in the room is the shape of the birdwing mast and it's patent defining its shape. I am a shape seller. After building and testing birdwing masts for the last ten years, I am more confident in the potential of its shape than I ever have been before. I am also 100% confident that the shape will reach its maximum potential in carbon fiber. However, there are several companies which could do a much better job of producing a carbon fiber birdwing than I could in my lifetime and with my resources. So let's talk a little about aircraft quality spruce. I totally agree that in just wood there's no way to make a birdwing mast strong enough but thank God for epoxy! I use 3/16" to 1/4" thicknesses on my laminations and generally use about ten layers or so to create a very strong mast.

    Another thing easy to miss is the birdwing mast's ability to rotate freely even while setting sail. This gives you the ability to load the rig as much as you would like (or as little) with mainsheet alone. Because the birdwing mast starts life as a very aerodynamically ideal shape it doesn't have to be bent or twisted to perform well. It's all in the shape. Because it lunges forward before it begins its big sweep aft, it has the ability to set balanced sail with just a single spar. This is a very good thing. It calms gybes and in general sets a very quiet sail because it simply does not create the turbulence that a straight mast makes when sticking straight up in the airflow. The difference is subtle but it is definitely there although I'm learning that it must be experienced to be appreciated or even believed.

    Because it can present swept back curvature along its entire length in the airflow, that's got to be good for working to windward as the drag of the rig must always be subtracted from the forward progress of a rig working to windward. There's no going back to a straight mast for me. The curvature that a birdwing mast presents makes way too much sense for me to turn back now. And it's not because of how well my latest prototype works now, it's because of how much better it can be when the shape is optimized by computers and computer operators much smarter than me and my laptop. Then when the optimized shape is realized then it's time to find a manufacturer smart enough to figure out how to build them in carbon fiber in this century.

    Sometimes I think I will be long gone before birdwing masts are commonplace but I know they are coming in the future no matter how much sailors like tradition and how accepting sailors are of what works correctly enough today. It begins by thinking of a sailboat mast as a foil rather than a straight stick. Not a foil as large as a wing because you could never turn the darn thing off as many people have already realized. Just a foil large and strong enough to set sailcloth that can be easily struck or set – that's ideal.

    The other thing that's easy to miss when looking at the birdwing design is the balance. Again, because it lunges forward before it sweeps aft, it offers a balance that's hard to appreciate unless you experience it yourself. Under bare pole the birdwing mast will self-rotate even under a slight amount of breeze to find the absolute minimum amount of aerodynamic drag as possible and with the birdwing shape, that is a very low number. I believe it is the lowest amount aerodynamic drag available for any shape that can also set effective sail area. So the shape offers extreme quiet at anchor and because it easily self-rotates to minimum drag and therefore minimum lift, it does not misbehave at anchor like a wing mast does. This too is hard to appreciate by me just telling you about it.

    In regards to Muri-Maru, one thing that needs pointing out is that when Muri-Maru is sailing on her lines, she is carrying 500 lbs. of ballast to make her self righting. This of course is best concentrated in lead but drinking water, salt water, pure ice, batteries, gear, fishing tackle, human beings all can qualify as ballast. So this provides a wide range of creature comforts for the captain of the boat. In the Texas 200 creature comforts are pretty darn important. It can mean the difference between surviving the event or putting one's tail between one's legs and slinking off to Florida in disgrace.

    I should also point out that Muri-Maru's ketch rig is so advantageous because I already have the mizzen mast and it's sail built because it is presently being used as the main mast on my present boat, a Welsford designed Saturday Night Special. One more mast and one more sail to build and I have a very powerful rig to drive Muri-Maru up the Texas coast in relative comfort in the middle of the summer and that, my friends, is saying a lot!!!



    Last edited by kenjamin; 07-26-2017 at 09:33 AM.

  7. #42
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by skaraborgcraft View Post
    ^ I agree with all of the above (i wont be building an oven). When it comes to deflection though, surely that can be an element that can be beneficial to anyone who is not a hard core racer? I recall a real competitive chap once waxing lyrical about the exceeding poor performance of a Freedom 40 ketch (free standing carbon masts), due to the issue of mast bend when hard on the wind in 25+knots; to him the loss of drive was speed over the water lost and possibly a race, to the Freedom owner it was a rig spilling wind and easing comfort. I might be wrong, but is there any point having such a stiff mast if it does not have an equally stiff hull below it either in hull form or via ballast? The weight issue i can really agree with, it helps with righting moment in a big way.
    I just sent a diagram i hand drew, via the scanner and attatched to an email as jpeg, have you upgraded to "new stuff", maybe that "cloud" thing....whatever that is?

    Whippy masts in way of gust response action (spilling wind) for lessening heeling effect on the boat is one thing when sail shape can be controlled, but I found the in-built mast bend to cause problems with the sail shape.
    Could be, that some more development work was needed, and that is why I bring up the carbon composites thing.
    Whippy straight masts can bend progressively, with sail twist having an axis, as it where, along a straight mast.

    With a swept back bent mast, there is a divide along a line through the sailcloth, between the mast tip and the point up the mast where the spar torsion is most evident…...which, in the case of the rig I tried, was a fixed point where supporting stays and shroud came together.

    Ken explains his birdwing to pivot as a unit, so maybe the balanced shape carries all rig rotation into the in-hull pivot bearing, and eliminates a crease running through the cloth.
    Could be, that his rig behaves more like the Freedom rig in gust response, and in which case there is flexing ratherthan torsion going on.

    Following directions on how to post pics and diagrams here, I am supposed to put them onto my website first. This is a process usually needing help from my stepdaughter, she has professional IT knowledge and is usually relied on for that sort of thing, which might involve the ”cloud thing”
    Right now I have more urgent tasks presssing, and she is busy with medical school studies…….i will get around to sorting it all when the time is right.

  8. #43
    Join Date
    Jan 2010
    Location
    Sweden,Scilly Isles, Siberia
    Posts
    7,948

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    I recall a friend who owned and raced an Everitt E boat (plywood), who went from replacing the alloy mast and boom to carbon, upgraded all the rigging, changed the running lines to spectra and eventually went over to laminate sails because the rig was stiffer than his sail cloth. He won a lot of races in his class which came at a huge expense. He reckoned the best thing to buy if you are serious about making your boat perform better, is new sails, he finally got beat by a standard boat whos sails had come fresh out of the bag that morning, though they did have an excellent tactician onboard...apparently.
    Sail set issue is a point though, i do wonder how wider/deeper midesection reefs down when it is trying to push its extra area aft, while the narrower head is forced into the opposite direction. I think the mast bands shown on the "Bernadette" rig could be adjusted to mitigate most of that issue.

  9. #44
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by Lugalong View Post
    ...

    Ken explains his birdwing to pivot as a unit, so maybe the balanced shape carries all rig rotation into the in-hull pivot bearing, and eliminates a crease running through the cloth.
    Could be, that his rig behaves more like the Freedom rig in gust response, and in which case there is flexing ratherthan torsion going on.

    ...
    Lugalong, I think in this picture you can see my mast flexing. One good thing about working in spruce and the way I build my masts is that the taper of the mast is able to be machined in with the router at the end of a 31' lever arm. The accuracy my set up provides means that the taper is beautifully controlled which I my mind means its not any stronger than it needs to be anywhere along its length. Also means it flexes along its full length without any hard spots that would invite it to break there.



    As Skaraborgcraft mentioned the mast bands that attach Bernadette's sail allow the mast to rotate sort of independently from the sail and they also create a slot effect which could prove to be beneficial to lift. It could be that more aerodynamically efficient mast bands (hoops?) might provide the most efficient sail set in a birdwing mast. More research needs to be done to explore these possibilities in my opinion.

  10. #45

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Wow! That is the most creative and exciting micro cruiser I have seen in a very long time. What a terrible temptation to place before an old codger with too much time on his hands. Those birdwing masts are the perfect addition of modern technology to such an old and traditional type of hull. It all blends together harmoniously, as if from a beautiful dream.

    What do you estimate her empty weight and displacement to be? That boat could take an aging adventurer who still hangs on to the illusion of youth to some beautiful places in style and comfort. I hope you build her. There is something special about seeing a dream such as this come to life. It makes all our lives a little more enjoyable. Best of luck - John

  11. #46
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Thank you, John. You just made my day. Very much appreciate the encouragement. Yes, JF Bedard of Bedard Yacht Design sure did an amazing job of bringing Muri-Maru to life at least in virtual reality. It will be up to me to build her for real. The hull will be just small enough to build in my 1 & 1/2 bay carport. The spruce main mast will be just small enough to machine in my backyard. Spruce it will be as it's already paid for and sitting in my dining room and my living room. It's what I know best. But if I use real bamboo for the sunshade, the spruce will look very good with the sunshade – at least it does in my mind. I asked JF to show the masts in carbon fiber because that is the current state-of-the-art material so that is what I chose for the renderings in the hope of having my birdwing mast design being taken more seriously.

    JF and I have plans to sort out the righting moment and ballast amounts next year when I have money back in the research budget. Between the big trip from Florida to the WoodenBoat Show at Mystic this year, paying for the 3D renderings and already purchasing most of the plywood and spruce I need, (and my stupid cat getting sick), I am one step outside the door of the poor house. However, Captain Short, the designer of the Yangtze Pelican called for 500 lbs. of ballast to make her self-righting – if that is any help. And my target weight of the empty plywood hull without ballast is about 800 lbs.

    Thanks for the kind words about my masts.
    Last edited by kenjamin; 07-29-2017 at 08:33 AM.

  12. #47

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    I do not have the technical knowledge to comment on the relative merits of spruce vs carbon fiber, but I have seen some amazing things done in home shop aircraft construction using spruce. The shapes achieved along with the strength and flexibility required by an aircraft in flight proves the worth of spruce for a free standing spar imho.

    Nothing else compares to the beauty of a wooden mast on a boat, even in an exotic shape, as you have already demonstrated. Your instincts and knowledge have served you well so far. They will continue to do so. - John

  13. #48
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Thanks John,

    Hopefully, the wooden spruce mast that I make for Muri-Maru's main mast will look as good as the mizzen mast I already have and am using on my Welsford Saturday Night Special as its main mast. There's no doubt that carbon fiber birdwings would perform better but building my spruce versions in aircraft quality spruce scraps is so much cheaper and a bit prettier (at least to you and me).

    Thought you might enjoy this new drawing I've put together which shows Muri-Maru motoring against a headwind on the left and sailing downwind on the right. I call this study "All or Nothing". Hope you like it.


  14. #49

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    I like it. The elegant masts with the tanbark sails make for an exciting look, rather like an exotic beauty before and after she dresses for the evening. Thank you for posting. - John

  15. #50
    Join Date
    May 2012
    Posts
    367

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    "... as fast as possible ...."
    Phil Bolger made a speciality of well-performing flat bottom small boats.
    Now i haven't checked your thread to see if it was previously covered - forgive me if so - but may i suggest you might fi d it worthwhile to check out Phil's "Buttock Lines".
    From memory he kept the bottom of the transom well [I]above[I] the water.
    Last edited by Frank!; 08-17-2017 at 04:25 AM.

  16. #51
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Hi Frank, I'm a big fan of Phillip C. Bolger's work and have three of his books, "Small Boats," "Different Boats," and "Boats with an Open Mind." Love the title of that last one and the pages of these books are well worn. I especially enjoy Bolger's honesty about his designs and he was not afraid to discuss what worked as well as what didn't work. I'm certain that he designed some efficient contours for flat bottomed boats for displacement sailing. However, when Captain William Short designed the "Super" Pelican hull which the Yangtze Pelican shares, I think he left the last part of the bottom having a flat run with the thought of encouraging the boat to plane so it's bottom design is quite a bit different than what Bolger designed for purely displacement hulls.

    What I think the hull will present is probably a slightly slower hull at displacement speeds but should really take off when she gets on a plane (no pun intended).
    The birdwing ketch rig that Muri-Maru will be using is quite a bit more powerful than the Yangtze original junk rig due to more square footage of sail area and my opinion of a more efficient sail design. Jeff Frank at Sailrite has been designing my sails for me to sew for the last ten years or so and he's getting pretty good at designing birdwing sails (also my opinion – not a claim)!

    With JF's computer redraw of the Yangtze Pelican, I'll be receiving full sized templates of both hull sides, both transoms, and all bulkheads so its going to be rather difficult for me as the builder to mess up. It remains to be seen how well Muri-Maru will want to plane and do that magical jump over the bow wave that makes so much difference in top speed. I've chosen the Yangtze design for my solution to surviving the Texas 200. In that event, there is usually plenty of wind to work with and as I said, more horsepower to work with in the new rig so it will be interesting to discover Muri-Maru's sailing characteristics AND FUN!!! I'm really looking forward to returning to the Texas 200 with a full-time sunshade over my head and hopefully completing the full 200 or so miles of the event. I only completed 35 miles of it on my first try back in 2016 due to getting badly sunburned on the first day. Full story on that here:

    http://forum.woodenboat.com/showthre...+the+Texas+200
    Last edited by kenjamin; 08-17-2017 at 01:31 PM.

  17. #52
    Join Date
    May 2012
    Posts
    367

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Ok Ken, I have now read the thread - very interesting! - and I feel much more in tune now.
    I see you have experience of the conditions (horrendous I reckon! in spite of the tailwind blast)
    I ha e two observations to contribute if I may.
    - re your ladder, from my experiments i find i need a foot hold at knee depth below the surface, and maybe one or more below tbat if ones knees are not strong.
    - and given your boat is such a big bouyant shape i would want a long tether to guard against separation in strong winds - there waz another thread on this.
    Rgds,
    Frank
    Oh and perhaps hand holes or grab ropes if o e has to swim round to the bottom to right the boat.
    Also i find it quite scary , e en on the trailer, to stand on the cabin roof and ztruggle with the mast

  18. #53
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Hi Frank, thanks for your interest in my Yangtze Pelican project. I had a lot of fun designing that rudder. I felt like a boat design with a name like Yangtze Pelican deserved an oriental looking rudder. It should be fairly easy to have a pull down sling on either side of the rudder cheeks that one could put their foot in to give a "leg up" on climbing aboard. There will be a big sling on each side of the cockpit space for pulling out and standing on to board the boat from the side. There will also be removable safety lines to ensure everyone stays in the cockpit and not ends up swimming in the water.

    What scares me is being tethered to a big strong boat that could drag me for miles. In the Texas 200, most of the time I'm so close to shore that I'd rather take my chances swimming but that's just because I have zero experience with using a tether. If I get more ambitious with my ocean sailing, I should definitely get more comfortable with using a tether.

    As for righting the boat, it will be designed to do that itself. It will take 500 lbs. of ballast for that to happen but that's the price you pay for that ability. Much of that ballast can be drinking water, saltwater, pure ice, high strength concrete, batteries and lead so I will enlist the help of Bedard Yacht Design to help me sort all that out. We have already agreed upon a price for that service and it is a very low price considering how much I enjoy living. At only 17' 5" the Yangtze Pelican is still a huge heavy boat to have to right with human power alone.

    As for stepping the masts, the ketch rig offers two fairly easily handled masts to have to step on the boat. The procedure is best done with the boat well strapped down to the trailer. Each mast step will also utilize a loading ramp to guide the foot of each mast down into proper position. I've also designed a locking mechanism that allows for a sloppy fit in the mast step at first that is later locked down into its final position with a polyethylene bushing. It works fine with the mizzen mast that I'm currently using as my main mast on my present boat. The main mast for Muri-Maru will be a little larger than her mizzen mast but hopefully not that much bigger to where it will be a problem.

    Someday, I may manage to build new birdwing masts in carbon fiber so that stepping and unstepping the masts will get even easier.


  19. #54
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    kenjamin, I wonder if you are able and could post some dimensions of this Prlican hull and to include the length of your spars.
    further comments by me of the birdwing rig would be more appropriate on the other thread, but since the Pelican was designed with a junk rig, this thread holds my interest.
    getting away from carbon composites makes sense, but sticking with he birdwing tends to steer things back to carbon all the time, whereas a junk rig is a good way to break away from carbon.

  20. #55
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Most of the dimensions are the same as for the Great Pelican only the Super Pelican and the Yangtze Pelican both have a longer and flatter run of the bottom at the stern of their hulls. As I said before, I think Captain Short looked for the Yangtze (and the Super) to plane when pushed hard or running before a blow in a storm. With the support board for a bowsprit a Yangtze Pelican would be 18' long but I'm building without the bowsprit (just like the junk rig, it has no bowsprit either) so without that board running up the face of the bow transom, the boat is 17' 5". The beam is 8' and the bottom is quite wide so she is very much a load carrying hull. Built for comfort, not speed. Also the Yangtze is a ballasted boat (500 lbs.) whereas the Great Pelican generally doesn't have ballast except some owners use water jugs of water to settle their Great Pelicans down a bit. (from what I've read)

    My masts will both be aircraft quality spruce and my mizzen mast is already made and has its own sail sewn already. My present mast is 21' long and made with about ten laminations. It seems to be very strong as it served me well in the thirty knot winds of the first day of the 2016 Texas 200. The main mast for Muri-Maru will be 24' long and slightly beefier than the mizzen.

    The reason I tend to show my virtual reality masts in carbon fiber is that those are the only birdwing carbon fiber masts that I can afford right now. I really like my latest spruce prototype as its fairly light for what basically is a solid mast but it has an internal halyard tunnel making it somewhat hollow.

    I tried the full batten treatment on my birdwing Caledonia Yawl but found the light air performance (especially to windward) not very good. My birdwing SCAMP went to windward much better with its partial battens but their was still quite a few wrinkles that I didn't like. My birdwing sail designed for my Saturday Night Special sets the best of all my prototype sails so far. It's shows some unusual loose belly along the luff in light air but really tightens up nicely with some wind to work with.

    For state-of-the-art performance almost everybody expects to see carbon fiber so to have any hope of having a mast design being taken seriously, or to encourage the building of my masts in carbon fiber, it might help to show them as they could be in carbon fiber. However, don't get me wrong. I appreciate the accurate taper I can machine into my masts when building in spruce and to my eye, they're prettier. (That's an opinion, not a claim.) They are also much cheaper to build. For an old retired graphics guy living on a modest budget and building a good sized boat, that's kind of important.

    Last edited by kenjamin; 08-18-2017 at 09:33 PM.

  21. #56
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Took the spruce mast off the top of my truck and put a couple of spruce masts on the Muri-Maru rendering. It's not perfect but gives a rough idea of what she will look like as actually built. The sunshade might end up being bamboo. The spruce mast on my truck is the actual mast that will be Muri-Maru's mizzen mast.


  22. #57
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by kenjamin View Post
    Most of the dimensions are the same as for the Great Pelican only the Super Pelican and the Yangtze Pelican both have a longer and flatter run of the bottom at the stern of their hulls. As I said before, I think Captain Short looked for the Yangtze (and the Super) to plane when pushed hard or running before a blow in a storm. With the support board for a bowsprit a Yangtze Pelican would be 18' long but I'm building without the bowsprit (just like the junk rig, it has no bowsprit either) so without that board running up the face of the bow transom, the boat is 17' 5". The beam is 8' and the bottom is quite wide so she is very much a load carrying hull. Built for comfort, not speed. Also the Yangtze is a ballasted boat (500 lbs.) whereas the Great Pelican generally doesn't have ballast except some owners use water jugs of water to settle their Great Pelicans down a bit. (from what I've read)

    My masts will both be aircraft quality spruce and my mizzen mast is already made and has its own sail sewn already. My present mast is 21' long and made with about ten laminations. It seems to be very strong as it served me well in the thirty knot winds of the first day of the 2016 Texas 200. The main mast for Muri-Maru will be 24' long and slightly beefier than the mizzen.

    The reason I tend to show my virtual reality masts in carbon fiber is that those are the only birdwing carbon fiber masts that I can afford right now. I really like my latest spruce prototype as its fairly light for what basically is a solid mast but it has an internal halyard tunnel making it somewhat hollow.

    I tried the full batten treatment on my birdwing Caledonia Yawl but found the light air performance (especially to windward) not very good. My birdwing SCAMP went to windward much better with its partial battens but their was still quite a few wrinkles that I didn't like. My birdwing sail designed for my Saturday Night Special sets the best of all my prototype sails so far. It's shows some unusual loose belly along the luff in light air but really tightens up nicely with some wind to work with.

    For state-of-the-art performance almost everybody expects to see carbon fiber so to have any hope of having a mast design being taken seriously, or to encourage the building of my masts in carbon fiber, it might help to show them as they could be in carbon fiber. However, don't get me wrong. I appreciate the accurate taper I can machine into my masts when building in spruce and to my eye, they're prettier. (That's an opinion, not a claim.) They are also much cheaper to build. For an old retired graphics guy living on a modest budget and building a good sized boat, that's kind of important.




    thanks, yes, the beam dimension is 8’ and is critical in my case. This is a bit too wide for the planned building space.
    Looking at some pics (found on another site) it is evident that there is a fair bit of space inside the after cabin) and with the biggish cockpit provided, there is potential for sheltered habitation as well as boat handling.
    In the case of your birdwing ketch rig, this cockpit space might be just what you need.
    Hiking out looks to be a possibility if you need the sail carrying stability with the extra canvas that your rig looks to have over the cat-like junk rig.
    Carrying more canvas with lower aspect sails in the split rig of your birdwing ketch seems to be what you are aiming for. which is fine if that is what suits your needs, and maybe the pelican hull suits that sort of rig and handling.
    If the idea is to keep it light and get up on the plane, it would make sense to keep everything as light as possible, including the rig.
    This is where carbon spars would help.
    Making them in carbon composites would be do-able ( as I keep telling you) mainly because you already have a wooden spar to use as a male form, that is of suitable shape to draw from the product once it is cured in situ (if you follow a procedure like I have developed).

    You could make a couple of them without spending on anything more than materials and consumables, if you are able to scrounge or hire a vacuum pump.
    So yes, for the purpose of keeping the weight down (at a price) the carbon fibre may have its place.

    As far as making a fortune by having a stake in the ‘advanced birdwing’ manufacturing and retail industry goes – maybe not much to hope for.

    It might be possible to develop the birdwing into a higher aspect shape, closer to something like a 5:1 ratio, if efficient Lift to drag is included in the ratio.

    Sticking with wooden spars and going with a Junk rig might however be an easier and more cost efficient way of making a higher aspect rig and will include an efficient reefing system.
    This type of rig will be better suited to powering a bulky displacement hull like a Yangtze Pelican, I think.

    So far in following this thread, I have been able to determine that this pram dory hull has proportions a bit too much spread in the beam, for my liking.

    Looking at alternative designs then, a double chine hull after Bolger of Michalak is more tempting.
    Sure, as already stated there is plenty of volume provided with an after cabin on a Yangtze Pelican.So, tying this feature in with providing support for a cantilever/free standing mizzen mast and also a bimini over the central cockpit, I can understand why the Muri Maru has something to offer.

    If however, nearly a quarter ton of ballast is to be carried, then the extra light spars seem a little pointless, as planning is not likely to be happening.
    Going with internal ballast rather than live ballast, puts things in a different light and is where the Junk rig and wooden spars as per the original design look to be good.
    Aspect ratio of the Junk sail is closer to n optimal 5:1 and there is a balance area foreword of the mast as well.
    Last edited by Lugalong; 08-20-2017 at 07:00 PM.

  23. #58
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    One thing I learned from the Texas 200 was that even with a boat that is carrying way to much weight (in the way of motor, gasoline, water, ice, lots of camping gear, food, safety gear, oars, paddle, a weeks worth of clothes and three pillows) that no matter how overloaded the boat seems to be, with enough wind it will still plane. (thirty knots seems to be enough) My personal speculation is that Muri-Maru will plane at some point – as you said probably not with the 500 lbs. of ballast aboard, but Muri-Maru's ballast amount will not be fixed in stone but rather a flexible number using as much water ballast as possible that still ensures self-righting. If anyone comes to town wanting to race their junk rigged Pelican against my birdwing Pelican, you could safely bet that Muri-Maru's ballast tanks would be bone dry for racing.

    Don't really understand your comment about making the birdwing design a higher aspect ratio shape – there's no problem there. I do not see any limit to how tall and skinny birdwing masts can become if that is the need or preference of the person paying for them. Sure at some point you may have to add stays but there's nothing that says you can't add stays. Birdwing masts could be designed to be as high aspect ratio as anyone could want. Would you like to see a birdwing rig with the same aspect ratio as an albatross's wing? Or an America's Cup boat? Both seem possible to me. Another thing that is easily missed is that although my prototypes all have a constant curvature along their curved portion (because of the way I make them), it doesn't mean the curvature has to stay that way. The curvature could vary along its length. The curvature could match whatever computer analysis dictates is the most efficient, most powerful, or fastest shape for any particular need, want or specification. I guess that's why I am not too interested in building some carbon fiber birdwing masts myself. Unless the money is in place to design a state-of-the-art aerodynamic birdwing shape for a given purpose and built with state-of-the-art carbon fiber fabrication and expertise, I do not see the point of doing anything less. My spruce masts are already doing what's less. I want to see my birdwing design aerodynamically optimized with computer design and built by people who actually know what they're doing – I could get excited about that. In carbon fiber, I would want them to be as perfect as possible within its design parameters (which are extremely flexible when you think about it). Anything less in carbon fiber would be a disappointment for me. And don't try to tell me there's no hope for the birdwing rig. There's always hope. I know because that's what gets me out of bed in the morning.

    Lugalong, what kind of length is your building space? Jim Michalak's Caprice might fill the bill for you. It's 25' long but only 6' of beam. A very interesting boat.

    Last edited by kenjamin; 08-20-2017 at 10:08 PM.

  24. #59
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by kenjamin View Post
    One thing I learned from the Texas 200 was that even with a boat that is carrying way to much weight (in the way of motor, gasoline, water, ice, lots of camping gear, food, safety gear, oars, paddle, a weeks worth of clothes and three pillows) that no matter how overloaded the boat seems to be, with enough wind it will still plane. (thirty knots seems to be enough) My personal speculation is that Muri-Maru will plane at some point – as you said probably not with the 500 lbs. of ballast aboard, but Muri-Maru's ballast amount will not be fixed in stone but rather a flexible number using as much water ballast as possible that still ensures self-righting. If anyone comes to town wanting to race their junk rigged Pelican against my birdwing Pelican, you could safely bet that Muri-Maru's ballast tanks would be bone dry for racing.




    Assuming my building space is limited to the garage at my pensioners pad, it needs to have no more length than 15’ and 7’ beam.
    This makes Jim Michalak’s Caprice a bit too long , although, the chine configuration is right and his Caroline design would be do-able I think, if I were to do some mods to build removable bow and stern sections that are bonded and glassed back on after leaving the garage.
    Working with pieces of a boat is something that I am getting used to doing.
    Perhaps it is a bit like you with the birdwing idea……. Something which I have started (about40 years ago) and won’t let go of.
    My proas are built like that ( in pieces, that start out small enough to be made in rented rooms or shipping container workshops, then joined together outside in the open air or under a tarpaulin.
    But before starting work on a plywood monohull, I really should make an effort to finish the SoPAHI ( Shunting Oceanic Pahi) proa that might still be assembled and launched while I still have access to the backyard laubch ramp.

    My comment about the aspect of your birdwing sail is best explained by applying logic to the guestion of optimized rig configuration.

    What I see looking at your rig, is a spar that could be lengthened between it’s step, and the kink where the curved upper part starts. This would increase the aspect ratio of the sail favourably and maintain the features which are apparently unique (being a rotating cantilever part stepped in the hull, and a curved upper part).
    As you say, the curved part could be just about anything you choose.
    Fact that what I see in all the pics shown, is clearly an arc, and this does makes sense when it comes to conventional composites fabrication.

    OK, I accept that fabrication is apparently inconsequential (as you imply) and that ‘optimized’ CAD CAM might produce something quite different.
    Who knows? 3D printing might even produce a replica albatross wing in synthetic tissue, of a nature never seen by any boat builder before this time.

    Sure! It would be interesting to see such a creation sailing, and if the vision of such a futuristic thing inspires you to keep on going, then all good and well.

    My own creative aspirations are limited to tools and materials that are immediately available and affordable.

    Could just be that you are right, about complex moulded or 3D printed foil shapes ultimately being more efficient than wings and spars formed or extruded within limitations of basic methods of fabrication.
    However, current design is not producing such complex shapes.Did you see how the TNZ guys rebuilt the wing of their foiling cat by hand laminating with brushes onto foam sheet, after it had come apart when the craft fell over onto it (‘pitchpoled’ in other words).

    This is ‘state of the art’.

    Also, you might have noticed how boxy th Formula 1 car bodies have become lately. Thre is very little ‘organic’ in their shape, but CAD has produced these shapes to perform at higher speeds and levels of efficiency than any of natures forms.

    Nature does not like or produce straight lines where wind or water flows.



    Don't really understand your comment about making the birdwing design a higher aspect ratio shape – there's no problem there. I do not see any limit to how tall and skinny birdwing masts can become if that is the need or preference of the person paying for them. Sure at some point you may have to add stays but there's nothing that says you can't add stays. Birdwing masts could be designed to be as high aspect ratio as anyone could want. Would you like to see a birdwing rig with the same aspect ratio as an albatross's wing? Or an America's Cup boat? Both seem possible to me. Another thing that is easily missed is that although my prototypes all have a constant curvature along their curved portion (because of the way I make them), it doesn't mean the curvature has to stay that way. The curvature could vary along its length. The curvature could match whatever computer analysis dictates is the most efficient, most powerful, or fastest shape for any particular need, want or specification. I guess that's why I am not too interested in building some carbon fiber birdwing masts myself. Unless the money is in place to design a state-of-the-art aerodynamic birdwing shape for a given purpose and built with state-of-the-art carbon fiber fabrication and expertise, I do not see the point of doing anything less. My spruce masts are already doing what's less. I want to see my birdwing design aerodynamically optimized with computer design and built by people who actually know what they're doing – I could get excited about that. In carbon fiber, I would want them to be as perfect as possible within its design parameters (which are extremely flexible when you think about it). Anything less in carbon fiber would be a disappointment for me. And don't try to tell me there's no hope for the birdwing rig. There's always hope. I know because that's what gets me out of bed in the morning.

    Lugalong, what kind of length is your building space? Jim Michalak's Caprice might fill the bill for you. It's 25' long but only 6' of beam. A very interesting boat.







    Assuming my building space is limited to the garage at my pensioners pad, it needs to have no more length than 15’ and 7’ beam.
    This makes Jim Michalak’s Caprice a bit too long , although, the chine configuration is right and his Caroline design would be do-able I think, if I were to do some mods to build removable bow and stern sections that are bonded and glassed back on after leaving the garage.
    Working with pieces of a boat is something that I am getting used to doing.
    Perhaps it is a bit like you with the birdwing idea……. Something which I have started (about40 years ago) and won’t let go of.
    My proas are built like that ( in pieces, that start out small enough to be made in rented rooms or shipping container workshops, then joined together outside in the open air or under a tarpaulin.
    But before starting work on a plywood monohull, I really should make an effort to finish the SoPAHI ( Shunting Oceanic Pahi) proa that might still be assembled and launched while I still have access to the backyard laubch ramp.

    My comment about the aspect of your birdwing sail is best explained by applying logic to the guestion of optimized rig configuration.

    What I see looking at your rig, is a spar that could be lengthened between it’s step, and the kink where the curved upper part starts. This would increase the aspect ratio of the sail favourably and maintain the features which are apparently unique (being a rotating cantilever part stepped in the hull, and a curved upper part).
    As you say, the curved part could be just about anything you choose.
    Fact that what I see in all the pics shown, is clearly an arc, and this definitely makes sense when it comes to conventional composites fabrication.

    OK, I accept that fabrication is apparently inconsequential and that ‘optimized’ CAD CAM might produce something quite different.
    Who knows? 3D printing might even produce a replica albatross wing in synthetic tissue, of a nature never seen by any boat builder before this time.

    Sure! It would be interesting to see such a creation sailing, and if the vision of such a futuristic thing inspires you to keep on going, then all good and well.

    My own creative aspirations are limited to tools and materials that are immediately available and affordable.

    Could be that you are right, about complex moulded or 3D printed foil shapes ultimately being more efficient than wings and spars formed or extruded within limitations of basic methods of fabrication.
    Did you see how the TNZ guys rebuilt the wing of their foiling cat by hand laminating with brushes, after it had come apart when the craft fell over onto it (‘pitchpoled’ in other words).

    This is ‘state of the art’.

    Also, you might have noticed how boxy th Formula 1 car bodies have become lately. Thre is very little ‘organic’ in their shape, but CAD has produced thes shapes to perform at higher speeds and levels of efficiency than any of natures forms.

    Nature does not like or produce straight lines where wind or water flows.
    Last edited by Lugalong; 08-21-2017 at 06:52 PM.

  25. #60
    Join Date
    Jan 2005
    Location
    Deepest Darkest Wales
    Posts
    18,450

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    This is interesting - and quite different to the usual - Kudos.

    One point bothers me - The aft cabin access hatch has a damn great lump of timber running straight across the top of it - possibly inconvenient.

    I'm no fan of wheel steering on small sailboats - but de gustibus...


    Might pay to take a look at the aft cabin and steering arrangement of the Fairey Atalanta where the lines from a whipstaff tiller are lead through the cabin to the rudder leavin the top surface of the aft cabin uncluttered.
    Last edited by P.I. Stazzer-Newt; 08-24-2017 at 08:12 AM.
    Someday, I'm going to settle down and be a grumpy old man.

  26. #61
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by Lugalong View Post
    Assuming my building space is limited to the garage at my pensioners pad, it needs to have no more length than 15’ and 7’ beam.
    This makes Jim Michalak’s Caprice a bit too long , although, the chine configuration is right and his Caroline design would be do-able I think, if I were to do some mods to build removable bow and stern sections that are bonded and glassed back on after leaving the garage.
    Working with pieces of a boat is something that I am getting used to doing.
    Perhaps it is a bit like you with the birdwing idea……. Something which I have started (about40 years ago) and won’t let go of.
    My proas are built like that ( in pieces, that start out small enough to be made in rented rooms or shipping container workshops, then joined together outside in the open air or under a tarpaulin.
    But before starting work on a plywood monohull, I really should make an effort to finish the SoPAHI ( Shunting Oceanic Pahi) proa that might still be assembled and launched while I still have access to the backyard laubch ramp.

    My comment about the aspect of your birdwing sail is best explained by applying logic to the guestion of optimized rig configuration.

    What I see looking at your rig, is a spar that could be lengthened between it’s step, and the kink where the curved upper part starts. This would increase the aspect ratio of the sail favourably and maintain the features which are apparently unique (being a rotating cantilever part stepped in the hull, and a curved upper part).
    As you say, the curved part could be just about anything you choose.
    Fact that what I see in all the pics shown, is clearly an arc, and this definitely makes sense when it comes to conventional composites fabrication.

    OK, I accept that fabrication is apparently inconsequential and that ‘optimized’ CAD CAM might produce something quite different.
    Who knows? 3D printing might even produce a replica albatross wing in synthetic tissue, of a nature never seen by any boat builder before this time.

    Sure! It would be interesting to see such a creation sailing, and if the vision of such a futuristic thing inspires you to keep on going, then all good and well.

    My own creative aspirations are limited to tools and materials that are immediately available and affordable.

    Could be that you are right, about complex moulded or 3D printed foil shapes ultimately being more efficient than wings and spars formed or extruded within limitations of basic methods of fabrication.
    Did you see how the TNZ guys rebuilt the wing of their foiling cat by hand laminating with brushes, after it had come apart when the craft fell over onto it (‘pitchpoled’ in other words).

    This is ‘state of the art’.

    Also, you might have noticed how boxy th Formula 1 car bodies have become lately. Thre is very little ‘organic’ in their shape, but CAD has produced thes shapes to perform at higher speeds and levels of efficiency than any of natures forms.

    Nature does not like or produce straight lines where wind or water flows.

    Sorry I was so long in getting back with you on this thread but I was off on my search for solar eclipse totality – it was awesome by the way.

    Lately I have become more serious about my study of birds. There's very few straight lines on them. James McMullen likes to post pictures of his area's buzzards and tries to make the point that their straight leading edge of their wings means that a swept back form like my birdwing mast must be a bad idea because hey, look at these buzzards! The truth is that even buzzards present curvature when it is beneficial to get to where they are going. I have a big dark asphalt parking lot next to my house in St. Augustine and the turkey vultures that we have around here daily use the updraft from the heated up parking lot of the hospital next door to climb altitude. I have a picture of one presenting curvature in its wings but I'd rather post it on my birdwing mast thread as I do not want to wander too far off the subject of Muri-Maru here.

    I want you to know I appreciate your contributions to the discussion. It really helps me to hear different opinions from folks out there in internet land. From reading back through some of your posts, I've come to realize that some of the stumbling blocks to the birdwing mast design may not have anything to do with the design itself but rather the boats on which they are placed. The point being that no designer has ever sat down and designed a boat around the birdwing mast. It could be that a boat with a birdwing ketch rig could be designed to hide a birdwing mast on each gunwale so well that they could be near invisible when stored and yet light enough and strong enough to be stepped quickly and easily. With the right scantlings such masts could be laminated spruce in my opinion – both cheaper and prettier! Could be a strong selling point for both mast design and boat design. This is the kind of thing I probably never would have thought of without blabbing about the birdwing mast on this forum.


    One last thing. You talked about how the latest race cars are getting more boxy. And I'm sure there's a good reason for that but yesterday I was watching "Chasing Cars" hosted by Wayne Carini, and the car auction he was attending sold an old Porsche long tail for 3.4 million dollars! So I guess that does say something for at least the style of smooth swept back lines. Porsche still makes a good living selling smooth curves.
    Last edited by kenjamin; 08-24-2017 at 09:24 AM.

  27. #62
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Quote Originally Posted by P.I. Stazzer-Newt View Post
    This is interesting - and quite different to the usual - Kudos.

    One point bothers me - The aft cabin access hatch has a damn great lump of timber running straight across the top of it - possibly inconvenient.

    I'm no fan of wheel steering on small sailboats - but de gustibus...


    Might pay to take a look at the aft cabin and steering arrangement of the Fairey Atalanta where the lines from a whipstaff tiller are lead through the cabin to the rudder leavin the top surface of the aft cabin uncluttered.
    Point taken about the inconvenience of the hatchway under that massive tiller. But my priority with Muri-Maru is to have a bulletproof rudder and tiller first and everything else is secondary. With the Texas 200 in mind, everything that is essential for survival will be there with me in the cockpit within an arm's reach away. No digging around for anything in the aft cabin during the day when I'm sailing. That aft cabin space will be utilized but only for stuff that I do not need during the day – camping gear, extra ice, extra drinking water and stuff like that. Plan to have the tiller swing up at anchor for access to aft cabin. My plan is to allow anything else on the boat to break or malfunction EXCEPT the rudder and tiller. If the wheel steering gives me trouble, I will just grab the tiller and cut the steering lines! If I do not have a knife and a backup knife on me, that would be the stupidest mistake of all.

  28. #63
    Join Date
    Apr 2007
    Location
    Singapore
    Posts
    11,676

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    What James McMullen really likes to point out is not really so much about buzzard wings per se, but rather that you haven't bothered to do even a cursory study of the state of the art of aerodynamic theory before coming up with wild and completely unsubstantiated claims about how your complicated, heavier, more expensive mast-like thingie is better than the carefully engineered, sophisticated, and well-tested rigs we see all around us.

    Kenjamin, I'll never forget the time you made the claim that a hawk curves its wings back when it wants to go faster--proving beyond a shadow of a doubt that you didn't understand the difference between generating lift for soaring vs plummeting.

    Quit being a crank and do some homework. Learn about how airfoils and boats work. Study successful modern and historic rigs and learn the theory behind their construction. And then do some properly designed experiments,with controls and valid sample sizes to test your ideas vs known quantities. Once you've actually got some data to prove you're right and every other modern sail maker and rig designer was getting it wrong all along then you can make your claims about how it's so much better. But you're desperately and defiantly putting the cart before the horse, amigo. Cut it out!

  29. #64
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    James, it's kind of silly for you to order me too study aerodynamics. Please look at things, at least briefly, from my perspective. I am an old 68 year old retired guy who does not have the time, money, or inclination to go back to school to learn anything! My budget is such that I only have money for a very excellent bicycle, boat building, oil painting, and trips to boat shows and chasing total solar eclipses. I only have time for bicycling my ass off and being in the best shape I have been since my college days of throwing frisbees and drawing naked women in figure drawing art class. Did you know you can get an art degree by drawing naked women? I am living proof. The only claim that I ever want to make someday is that I am an artist and I am certainly not there yet but that is my main ambition. I also want to build Muri-Maru in order to successfully shade my pale white freckled skin full time so that I can sucessfully complete the Texas 200. Making millions of dollars on the birdwing mast design is not really a huge priority of mine and never has been. Sure, I dream about the possibility of buying another brand new Mazda MX-5 someday but I'm loving my truck for its ability to take me, Bernadette, and my funky birdwing mast to far away places like Lake Nantahala, NC where Bernadette and my birdwing mast were very well received and I met a bunch of nice people as the result.

    I am a retired crank and there's no escaping it. I do exactly what I want to do on an hourly basis. If I want to take a nap at 11 am, guess what, I do it. If I want to ride my bicycle 26 miles around St. Augustine climbing all three bridges, guess what, I do it. Then if I want to lay around the rest of the day watching HGTV or Velocity Channel or HBO movies, guess what, I do it. When you finally retire I highly recommend that you also do exactly what you want to do on an hourly basis. It's what smart retired people do.

    The other thing that you so conveniently ignore is that the birdwing mast design and I are joined at the hip. The design is patented and I am the inventor and now the owner of the patent. I do not have the time, money, or inclination to abandon the design now just because you think it has no potential! Its curvature and sickle shape and self-rotating (under bare pole) abilities are given attributes which the design has, in my opinion, and have been observed to be benefitial by me and you and no one else is going to convince me that the design is not worth developing further. Because I am a retired crank, I will do that by building a boat like Muri-Maru because that is something I actually enjoy so boatbuilding is on the menu of fun things to do today. You have to embrace the retired mentality to actually enjoy being retired. Maybe someday you will understand.

    Hawks do fold their wings back closer to their bodies for more speed when plummeting so I do not understand that comment at all.

    And lastly, I want you to know that I really do appreciate your comments and participation on my threads as I tend to learn more from negative comments than I do from people coming up to me and saying "Hey, I really like your curved mast. That's really something!" Similar comments were made by many folks on the lake with me at the solar eclipse totality on Lake Nantahala Monday. For me, as an aspiring artist, their comments mean a lot to me. I am not an aspiring aerodynamics authority. I will gladly leave that territory for folks who are already there! The truth is it's much easier to pay (or get someone else to pay) for aerodynamic expertise than to stop everything and learn it myself. And I'm pretty darn sure at my age, that would be darn difficult or just impossible. As dirty Harry said, "a man's got to know his limitations". Me as an aerodynamics expert is just not a possibility at this point in my life especially when considering all my boat building, bicycling, and oil painting that I simply must do to make me happy.

    I have been very lucky with the patent. When FSU saw Xena and her birdwing mast they waived the requirement that I had to have an interested business partner waiting in the wings (so to speak) and they decided to pursue the patent. It was their decision, not mine. That the Vice President of Research at FSU decided to sell the patent back to me for a dollar that was his decision, not mine. What I wanted was for them to research the design and see exactly what it could offer aerodynamically while still retaining its obvious talent of storing better in the boat. I would have been very happy to have much more brilliant minds working on the problem of developing the design than my artistically inclined age-incrusted brain that I am dealing with today. So cut me some slack, dude! I may yet create some good art on down the road but the idea of me becoming some kind of aerodynamics expert is completely unrealistic!!! I'm not putting the cart before the horse. I just want to see how much better the cart can get for the horse. And I sure as heck hope I can get better minds than mine working on the problem someday. If not, frankly, being an old crank, I don't really give a damn.

    I had a very poignant Monday.

    Last edited by kenjamin; 08-24-2017 at 01:28 PM.

  30. #65
    Join Date
    Feb 2006
    Location
    Pennsylvania
    Posts
    7,714

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    One last thing. You talked about how the latest race cars are getting more boxy
    A note on this aside: those cars are built to what's essentially a box rule. All the wing parts have to fit into an imaginary box, so naturally the designers use all the space they are allowed, creating a boxy shape. If it weren't for the rule, the cars would probably be a lot more attractive. Another curiosity is that the Indy cars are by definition "open wheel" cars. But open wheels are bad for aerodynamics, so the designers do everything they can to enclose the wheels, or at least get the airflow off them, without breaking the open wheel rule. Again, if it weren't for the big rulebook, the cars would have much more flowing, organic shapes.

    Here's a sample of the most highly engineered wings for sailing. As far as I know, the shape of the leading or trailing edges are not regulated. Is the C-class cat mimicking a bird's wing, too?

    -Dave

  31. #66
    Join Date
    Mar 2002
    Location
    Duncan, Vancouver Island
    Posts
    26,680

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    I was quite good at making images of naked women in art school but found it too distracting and moved on to other imagery. I have no opinion on the birdwing except to say that it's a lovely thing to look at and so I'd rather see it on something other than that Pelican you have remained so fond of over the years. I wish there was something I could say to encourage you to at least redraw those cabins, but love is blind.
    Last edited by JimD; 08-24-2017 at 03:55 PM.
    There is no rational, logical, or physical description of how free will could exist. It therefore makes no sense to praise or condemn anyone on the grounds they are a free willed self that made one choice but could have chosen something else. There is no evidence that such a situation is possible in our Universe. Demonstrate otherwise and I will be thrilled.

  32. #67
    Join Date
    Apr 2007
    Location
    Singapore
    Posts
    11,676

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    1. I am retired, and enjoying life living overseas and traveling the world, thank you very much,
    2. I only "demand" that you study aerodynamics if you're gonna keep making wild claims about the supposed amazing aerodynamic improvements of your mast thingie. If you'd just stick to the known facts instead of hurling about unsubstantiated speculations as if they were actually proven and demonstrated, I'd shut up about it, with pleasure. If you wanna make claims about how you think it's prettier, or provide an argument that stowing a mast against a gunwale is more important than having a lighter, simpler, cheaper, and easier to build mast, then again, I don't care. It's your shameless hucksterism of a poorly researched concept that really gets up my nose.
    3. Look up "Sunk Costs Fallacy". I think the FSU researchers who were perfectly willing to turnthe patent back over to you for a dollar understand it just fine.
    4. Despite all that, I do want you to have exactly the boat you prefer. To each cat his own rat. Just quit making irresponsible claims.
    Last edited by James McMullen; 08-24-2017 at 06:40 PM.

  33. #68
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    425

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Talking about slippery shaped bodies and the way they travel through air is not quite the same thing as about forms /foils used for maximizing lift whist reducing drag, although, car bodies could be equated with hulls and superstructures. But only if their wings (for down thrust) are removable appendages.
    Reducing frontal area helps to cut drag, but does nothing for lift or down force.
    A different set of compromises needs be met for cars compared to sailboats.
    Agreed though, the ‘aero’ swoopy shapes of sports cars like the Porche 917 did edge toward apparently natural curves.

    Even so, competitors of the same era managed well with the blunt Kamm tails and there is no clear cut answer to which was best in general.

    Comparing Muri Maru to any car, would have to be something of the Model A vintage.
    However. powering a Model A with a supercharged V10 would be as pointless as putting a multi element carbon composite wing on a pram dory.
    Spruce birdwing spars might be more than powerful enough to match the hull form.
    This is where it would be interesting to compare the performance of the same boat with a higher aspect sail of the Junk type on a single mast, rather than a split rig.
    Cut and set of sails could well be the deciding factor here.

    Choice of the Junk as comparison is because it also has a free-standing mast with optional stays ( just in case stays have to be included).
    Balanced sail area forward of the mast is the other feature in common with the birdwing and it would be interesting to know how much better this balance area might be without mast turbulence on the w/ward side.
    Here the birwing might just show it’s heels.
    A simple fix for the Junk rig might be a split sail with the forward panels being separate ‘jiblets’.
    OK, a birdwing mast will theoretically have less frontal area (due to t’s ‘slick shape’)definitely less than a masthead and yard of a Chinese lugsail, but of course the lug can be dropped at anchor to lose this wind resistance area, so the pitch for birdwing superiority at anchor is overrated.

    When sail is set, the higher aspect lug’sl has more area and power up where air flows faster, so we could expect to see a performance gain here.

    This is where the fat head or square head mainsails are an improvement on jib headed sails.
    Controlling this part of the sail is where a Junk has no problem.

    Lower down the mast, there is no difference between requirements for a Junk and a birwing, except that the Junk does away with complication of rotation.
    Sure, it would be interesting to know how much lighter a wooden birdwing spar could be in comparison to a Junk rig, given equal sail area.

    If the birdwing sail is hands down better on all points of sail, there might be a chance that a birdwing puts up a good showing against other rigs of equal weight, cost and sail area.

    However,when cost and difficulties in requirements for building climb (workspace and tooling), I question the validity of the rig for a simple plywood boat.
    Could be that the Yangtze Pelican is the answer then.
    I certainly do like the position of the board and rudder in your renditions.
    Agreed too, is that the rudder must be very robust and here again the Chinese type assures this.

    The biplane rig idea is certainly novel. Might as have twin rudders in that case?
    Last edited by Lugalong; 08-24-2017 at 07:07 PM.

  34. #69
    Join Date
    May 2005
    Location
    St. Augustine, FL
    Posts
    3,483

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser



    I only want the best for my invention. If you were in my shoes, that is what you would want as well. In my eyes, that would be a team of experts optimizing the aerodynamic shape of the birdwing mast while still retaining its definition as stated in U.S. patent #8,739,720. That team of experts would utilize the best computers available, the best software, and eventually the best slow speed wind tunnel available to optimize the shape of an excellent example of a birdwing mast. Then that resulting design would be handed off to another team of experts who could figure out how to build the thing in carbon fiber where most of us would agree the best performance potential for the design lies. That is exactly what I wanted FSU to do with the design when they owned 100% of the patent. They bailed on me so I will continue on in my quest for the ultimate birdwing mast in my own way.

    My plan now is to bring attention to the design the best and most fun way I know of and that is building more masts and a new boat on which to step them. I chose the ketch rig for Muri-Maru because two smaller masts are easier to step by one person than one big one and also I already have the mizzen mast and sail as that is the rig I’m presently using as the main on my Welsford Saturday Night Special. So you see, almost half of Muri-Maru’s rig is already done.

    My ambition for Muri-Maru is that she takes very good care of me in events like the Texas 200 and that I continue learning more about my birdwing mast design. I have hired a talented young boat designer to help ensure that Muri-Maru is self-righting, well balanced in her rig and foils, and nearly unsinkable while still retaining an expected 8 inches of minimum draft.

    She will not be a fast boat but she should be one heck of a load carrier able to bring all the comforts of home with me during the five days of hellish conditions often found in the Texas 200. An air-conditioned aft cabin space would be nice for resting and sleeping at anchor if I could possibly afford it and find a small enough marine quality unit.

    She may even make a big enough splash in my sailing adventures to help me find assistance in developing the birdwing mast design to its final optimal form and construction. Although my efforts are much more of a hobby than a “get rich” business plan, who knows what will happen in the future? In my opinion it’s the “not knowing” part and the potential of the design that makes it so much fun!
    Last edited by kenjamin; 08-25-2017 at 05:41 PM.

  35. #70

    Default Re: Muri-Maru, a 17' 5" birdwing Yangtze Pelican microcruiser

    Hey, Kenjamin. A thought on your sunshade. You could make detatchable curtains of the same fabric used for sunshades on cars, the fabric that blocks 70% of the sunlight but still allows you to see through it. That way you can keep a shade up in the direction of the direct sunlight. Good luck with your build - John
    Last edited by Landlockedvoyager; 08-25-2017 at 02:31 PM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •