Future physics of a birdwing mast design

[kenjamin]

Let's not get too far off topic, Kenjamin, but I think you have very much still to prove on your assumption that you have made anything more efficient with your "birdswing" mast rig thingie. I won't argue if you say that you like the way it looks or that you're happy to shut up your loud-mouthed fishing buddy who complains about a mast in his way, but until you prove that your rig goes upwind better or even as well as a competently handled, lug rigged version of a CY, you'd better stop making that sort of outrageous claim. I don't think you have the slightest bit of data to prove your too-flat, wrinkly, stiff-battened sail with that big sculptured and curved stick with its uncontrolled rotation impeding the luff flow has less drag than a modern dacron lugsail with its gloriously unobstructed and efficient leading edge. You still haven't sailed side by side with a CY constructed to Iain's stock plan yet, have you?

There's nobody--including long-time modern fiberglass sloop owners (like myself, formerly!) who would complain about how well a CY with a good lugsail goes upwind. And in my opinion, it's a vastly simpler, handier and more cost effective rig than a heavy, laboriously sculptured, axially unbalanced, curved spar with full battens and sail slugs that need to be inserted into a luff groove to set sail.

When I get accused of something, I like to be at least guilty of it. It has been years since I have made any claims about the imagined performance of my birdwing mast. In fact, it was Mr. McMullen himself that made me think I should stop making claims about the projected performance of my birdwing mast design until it has been actually tested and that was years ago. My birdwing mast is an ongoing experiment which has very little actual data to support any claims about its performance except for maybe the big silly grin on my face every time I use it. I would like to compare it to a conventionally lug rigged Caledonia Yawl but so far the timing has been wrong. Lots of things in life can get in the way of pursuing one's hobbies and having your wife become ill and die is one of them.

I will someday hopefully get to test my rig against existing rigs and maybe that information will be helpful. Often prototypes do not work as well as they do eventually when they actually go to market and that could be the case with my birdwing mast. Notice I said "could be" rather than "is".

Here is what I do know about it so far:

1) The battens do not have to be inserted every time you set the rig. The plastic slugs sliding in the plastic-lined luff groove are super slippery and work great!

2) In it's present state (second prototype) it is heavy but very stiff especially in the fore/aft direction. This may or may not help it set headsails more effectively than some other unstayed rigs. Having said that there is a place along the length of the mast so near the axis of rotation that stays could probably be fastened without much affecting the free rotation of the mast if the extra complication of stays were deemed advantageous to the normal operation of the boat.

3) Some people really like the way it looks. Some people seem to hate it. Some people have commented that it is a work of art. Others only see the wrinkles in the sail. No big surprise to me in the wide range of reactions to it. All comments from people who have seen it in person have been favorable to my ears. Some people may have been holding their tongues as they thought negatively. Sometimes peoples' jaws drop and no actual words come out.

4) For many years I have had fun designing and building things I'd like to try. These include masts, one-speed bicycles, houses, wooden cameras, winged surfboard skegs, and a pontoon for a tippy tender dory. I have fun experimenting with things and probably will not make any claims about their performance unless I can back it up with real world testing. My houses are still standing. My wooden camera can still take pictures. I can still ride my one-speed bicycle to work in spite of the nasty hills in Tallahassee. Xena, my boat, with its funky mast brings me much pleasure. Many thanks to Iain Oughtred for the efficient hull and for permission to experiment with the rig for it. Yes, I regret butchering my CY's sheerline but I promise to stay true to the hull lines in future builds of Mr. Oughtred's designs.

5) Once the mast is stepped, the rig goes up quickly and can be struck even faster and at 2 lbs. the composite reinforced bamboo yard at the head of the main is harmless when compared to the yard of the hoisted lugsail. I have been in Patina, a gorgeous, conventionally lug rigged Caledonia Yawl, when the yard accidentally dropped resulting in a loud noise when it landed in the bottom of the boat and I sure wouldn't want that thing falling on my head – accidentally or not.

6) I don't know if my birdwing mast design will ever go to market as a viable product but I have had a great time messing with it and will continue to do so. I do look forward to testing it against conventionally rigged Caledonia Yawls when the opportunity presents itself. I'm not much of a sailor but it sure seems to handle nicely especially when there is the good stiff breeze for which it has been fashioned to address. I also can't wait to build the new mizzen birdwing sail and a new genoa sail kit on my new Sailrite sewing machine. They may (that means "maybe will") help with light air performance if the laws of physics continue to stay the same.

http://www.bodaciousboats.com/CastilloDeSanMarcos.jpg

[James McMullen]

Awesome, Kenjamin. You rock!

[James McMullen]

The conventional CY type rig for illustration purposes:

http://inlinethumb15.webshots.com/42254/2475785700088484686S600x600Q85.jpg (http://sports.webshots.com/photo/2475785700088484686LWCItB)

And with a reef tucked in:

http://inlinethumb03.webshots.com/40450/2968773630088484686S600x600Q85.jpg (http://sports.webshots.com/photo/2968773630088484686zyVgyn)

[Thorne]

The look of the birdwing mast and sail shape is similar to the Norseboat's curved gaff, and in my eyes nicer.

http://www.norseboat.com/NorseBoats_files/norse4.jpg

[Steve Paskey]

My birdwing mast is an ongoing experiment which has very little actual data to support any claims about its performance except for maybe the big silly grin on my face every time I use it.

That seems like data enough to me.

[donald branscom]

I like the conventional rig better. And I bet it is MUCH cheaper!!!!

[mcdenny]

Ken,

What Steve said, it's supposed to be fun - if you are having fun it's a success!

BTW, ought to be lots of opportunity for side by side comaprisons to other Oughtred designs in Mystic next summer. Sure wish I could bring my AT.

[wtarzia]

I've always liked the sail aesthetically. Does the mast/luff geometry prevent smoothing the wrinkles with a sort of cunningham device pulling at an angle into the tack? And so the wrinkles smooth out anyway when the wind stiffens? (like my standing lubgs, with their wrinkle from downhaul tension, which smooths out when when goes over 5 mph). -- Wade

[kenjamin]

Thanks for all the comments, guys. I always seem to learn something new when I author a thread about my mast – even from the not-so-favorable comments. It keeps me thinking of ways to improve the design in the future.

My mast design was indeed very expensive to construct. The way it was built wasted a lot of very expensive Sitka spruce and if I had used less glue and more consistent wood thicknesses it would no doubt have turned out lighter with a better weight to strength ratio. On the other hand, if it wasn't difficult and expensive to build, someone may have tried it before me. Iain Oughtred did send me some pictures of a Dutch boat that had masts with extremely curved profiles but that was after I told him what I was up to and had already asked him in writing for permission to proceed. Also I don't think those masts had the same transition area where the curvature becomes a round cross section and therefore able to rotate freely in the mast step. In any case, those masts have broken in use and mine has not.

http://www.bodaciousboats.com/Letter.jpg

I recently bought a Gary Fisher Simply City bicycle which incorporates aluminum sections which have been formed by water pressure or hydro-formed as they say. I can't help but wonder if that technique could be applied to sailboat masts so that their shape could be more complex in a mass production process and yet be made of recycled aluminum to help make the final product affordable. Of course, it would take a huge investment to find out but if the shape itself can prove its worth in wood, then someone may want to find out what it can do when rendered in aluminum or perhaps carbon fiber/epoxy. My guess is that carbon fiber/epoxy should be the next step because the molds would need to withstand much less pressure and resin infusion has been proven to work well for one-offs of designs. If it worked really well in carbon fiber/epoxy then maybe it would be worth rendering a final version in hydro-formed aluminum. Who knows, with the recent advancements in 3D CNC machining, it could be that machining of laminated wood blanks could be the most cost effective way of creating a production birdwing mast for the masses.

For myself, I'm very curious if I can do a better job of the thing for a larger boat like maybe Mr. Oughtred's Haiku. Time will tell but until then I am very much enjoying Xena.

Wade, I've purchased the parts for a makeshift cunningham but have not installed them yet. I also need to taper my battens as Todd Bradshaw suggested for a more powerful sail shape but I haven't gotten around to that either. If I'm going to race other CY's at Mystic this year, you can bet all that will get done in preparation but that sure is a small pond on which to do any real meaningful racing not to mention the liability. If someone wants to square off at dawn on Sunday with a conventionally rigged CY, Xena and I would probably be willing.

There's already quite a bit of power available from the present sail (wrinkles and all) as you can probably tell from this picture of Xena busting through a boat wake on Matanzas Bay, St. Augustine, FL.

http://www.bodaciousboats.com/HeadedHome-sm.jpg

[John Meachen]

If nobody ever ventured from the accepted norm,its hard to see where progress would come from.I look forward to seeing the results of your direct comparison with a conventional rig.In the meantime you have had some interesting experiences with the development path you have chosen.

[StevenBauer]

The sail shape on the dutch boat that Iain mentioned seems to have a much better sail shape. That's my main concern with the concept. Aside from the expense and complexity.

http://im1.shutterfly.com/media/47b7cc24b3127ccec29eb80ef84d00000010O00AbNnLhizaOW IPbz4S/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

http://im1.shutterfly.com/media/47b7cc24b3127ccec29fdf5419c000000010O00AbNnLhizaOW IPbz4S/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

I think Kees Prins built this boat.He might live in the Pacific NW now. Port Townsend, maybe?


Steven

[James McMullen]

Kees Prins does live in Port Townsend right now. He bought that Oughtred Fulmar from me last fall, and is currently refitting it with a micro cabin for minimalist cruising accommodations. That boat had a curved gunter yard--which always gave me fits with un-fixable wrinkles and poor control of sail shape at the head too. No amount of peak outhaul or fiddling with individual robands could account for all those changing variables as the wind increased or decreased. Distributing those straight line vector stresses along a fixed curvature spar is a lot trickier to handle than starting with a straight spar that is flexed into a curve such as Windsurfer or Laser sail rigs, methinks.

[Paul Pless]

If one wants to see a high performance (especially to windward) sail bent onto a mast with loads of prebend and adjustabilty, then you need look no further than square meter yachts... some square meter yachts also boast unstayed rigs or partially stayed rigs and rotationg masts. Such innovation has been going on in that class since 1910 or so.

[James McMullen]

Yes, no question that bendy masts, as opposed to rigidly pre-bent masts, have had a long and successful development in the racing world. The reasons for and the methods and mechanics of adjustability of a bendy rig are not using the same rationale behind the "birdwing" mast Kenjamin is experimenting with, however. There are no methods for adjusting sail shape and camber through backstay tension, sheeting from adjusted traveler settings, boom vangs, cunninghams, leech lines or clew outhauls, nor controlled spar rotation on the "birdwing" rig--or at least not yet.

Apples and oranges.

[Todd Bradshaw]

Battens first, then maybe a Cunningham, though their function is to flatten the sail and/or move draft forward, not to remove wrinkles and I doubt one will have a great effect as a wrinkle remover. Wrinkles aren't terribly pretty, but I think your first goal in order to get good performance has to be getting some draft in the sail. You are running into a problem having a cross-cut sail, where the warp yarns are diagonal to the water and perpendicular to the leech (as they should be) but the battens aren't diagonal, they are level to the waterline. This means that they are intersecting the thread lines on a bias. Your most powerful sail-shaping tool (batten tension) is being applied to the fabric's least stable dimension (on a bias). The fabric is stretching, rather than holding its shape along the battens.

I cut one of the sails I built for our iceboat that way, and even though it's only about 65 sq. ft. and made from very heavy Dacron, it's really touchy about batten taper and flexibility. The shape and draft on sails cut like this have to be achieved more by batten flex than by batten tension if you want a smooth sail. If you give it the old Hobie Cat-style "tighten the stiff battens until you see an airfoil and the draft you desire" treatment, about all it's going to do is wrinkle along the battens and eventually stretch the sail along the pockets to the point where in may not recover. A set of really good (probably composite) tapered battens might do wonders for the boat's performance and also get rid of most of the wrinkles. Notice that the Norseboat that Thorne posted is showing a little bit of the same wrinkle problem and likely for the same reason. However, notice also that the sail has pretty decent draft. Both of these improvements are probably being caused by better, softer battens. The non-battened sail in the magazine, avoids this problem and is pretty much a no-brainer to cut once you have a basic grasp on the mast's flexing characteristics in use.

[Steve Paskey]

http://im1.shutterfly.com/media/47b7cc24b3127ccec29eb80ef84d00000010O00AbNnLhizaOW IPbz4S/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

I think Kees Prins built this boat.He might live in the Pacific NW now. Port Townsend, maybe?

That's really interesting. It reminds me a bit of the "crab-claw" sails used by traditional cultures in the south Pacific.

[kenjamin]

Nobody said it would be easy. Getting a sail to set correctly along a stiff curved mast is a whole new can of worms which may or may not be worth pursuing. Of course we'll never know until it is tried more than a few times. Didn't Thomas Edison try almost a hundred different filaments in his electric light bulb before he found one acceptable? My premise for a stiff curved mast was so that it could more effectively set head sails without ruining the set of the main. The other benefit is that it is a brute of a mast and while a bit heavy at 42 lbs., it enjoys the fatigue resistance of laminated wood and its shape will shed water as well as it sheds air in the event of a capsize. My mast, in all likelihood will outlive me and my nephews and maybe their kids.

Sailing to windward, there's no escaping the fact that you have to subtract the aerodynamic drag of the mast from your forward progress. If you can create a mast which has very low amounts of aerodynamic drag and design a sail which works correctly in harmony with that mast then you may have something. Another wrench in the works is that my mast rotates in it's step very much on it's own (even bare-poled) to present the least amount of wind resistance as possible. It could be a long while, perhaps long after I'm dead and gone, that truly aerodynamically slippery (now there's a phrase for you!) masts find the appropriate sails that can work in harmony with their shape.

Sometimes it's not that important arriving at your destination as long as you're headed in the right direction. I'll always maintain that it just makes sense to have an aerodynamically slippery mast when going to windward. Whether sails can be cut to work correctly with that slippery mast is a darn good question at this point in time.

James, could you put me in touch with Kees Prins or at least tell him about the discussion of his masts on the forum?

Todd, are you saying I should also change the angle of the batten pockets? That's something I could actually do. I will get around to tapering the battens that I do have – I promise!

[wtarzia]

That's really interesting. It reminds me a bit of the "crab-claw" sails used by traditional cultures in the south Pacific.

--- And because both spars are curved to match, you can add brailing lines (on each side of sail) to brail up the sail in a reasonable bundle (like some of the Pacific crabclaws), which in my experience with the crabclaw was a handy feature (though not as good as reefing, if you have a sail that might not come down in a hurry, fast brailing is an essential quality. The brailed sail+mast then can be more safely taken down as when on the beach in a stiff wind). -- Wade

[James McMullen]

Here's a link to Kees' homepage (http://nwmaritime.org/index.php?page=kees-prins).

Low aerodynamic drag is not the same as high lift. Lift is the the most important factor for upwind sailing. A too flat sail has much less lift than a properly cambered foil.

(By the way, have you measured the actual drag of your tall, heavy, curved, freely-rotating spar in comparison to the aerodynamic drag of the lighter, smaller section of the shorter lug-rig mast? Is your spar actually less drag, or is this an untested assumption, because you made it look all streamliney? The height above the surface and total length of spar are important measures for actual windage. Some scale model testing might answer these questions.)

High drag is actually desirable in some sailing regimes (ie: downwind courses)

[kenjamin]

Thanks James, you da man!

Hey, don't forget to add the drag of your lug's yard when the comparison is measured. Also my wooden prototype is not nearly as streamlined as it could get in later more refined versions. It's only my second prototype. Give me a few more tries to get it right. Later versions could be much slicker, computer machined or formed by computer machined 3D molds. Cut the prototype some slack and think of how it could be optimized to shed the wind, not how it is now (shaped by eye in my garage with a 4&1/2" grinder). It's not so much where the invention is now that matters. It's how far the idea can be taken to increase windward performance that matters, not its present state. Think into the future. If the shape is correct, someone will figure out how to render it.

[kenjamin]

By the way, it already works great downwind, quiet and controlled:

http://www.bodaciousboats.com/Downwind.jpg

[Todd Bradshaw]

I would not move the batten pockets at this point, leaving a couple lines of ugly holes and a potential weak spot. However, you do have to figure that if your panel fabric goes one direction and most likely, your pocket fabric (which is sewn to it) is made from strips woven a different direction, it doesn't present a very good scenario for something that is stable and wrinkle-free when under tension. It's like the old corner patching rule of matching the weave direction of all your corner patches to the weave of the panel below them. This is done to help prevent wrinkled corners once they get some tension on them.

Though not terribly uncommon (it's often seen in cases where folks want their full battens level for reefing purposes - especially roller-reefing on cross-cuts) this sort of mixing of weave directions and then applying batten tension to it can be a very effective formula for creating a lot of pesky wrinkles. A better solution seems to be good tapered battens that naturally want to bend much more in some places than in others without needing to be cranked down tightly with batten tension. Under wind pressure alone, the battens will want to take their proper, airfoil shape, hopefully without having to bring the unmatched weaves, battens on a bias, and the wrinkles that they cause into the equation. Unfortunately, really good tapered battens like this are expensive and not a very do-able project for most home-builders.

[James McMullen]

Uh. . . .I don't think it should be optimized to shed the wind. . . .I think it should be optimized to harness the power of the wind in developing lift. . . . .

. . . . .and what's more, do it in a way that is as cost and time effective to build and maintain, and is as durable, versatile, efficient, lightweight and handy to use, set, reef and stow as other existing rigs.
I would also point out that you have yet to demonstrate that this style of sail rig offers superior or even comparable windward performance, especially per square foot of sail area, or dollars, or time spent, or ease of use setting and striking the rig, but by this point that would just be repeating myself.

[Paul Pless]

go james go

[kenjamin]

James,

Lucky you. You have a cheerleader!

Yes I agree that windward ability is only one facet of a rig's performance but it is an extremely important one. Yes I agree that to be marketable, it has to be produced in a cost effective manner and be somewhat practical but that kind of stuff can come later if the concept of the curved shape is deemed advantageous. We can only find that out by trying. It seems that I will continue trying to improve my mast's effectiveness and you will continue to state how wonderful your rig already is. You are happy with the present state of the art and I am curious about the future. I suspect there's room on the planet for both trains of thought. Thanks for being the one who holds up the banner of what's working great as it is now. I appreciate your comments.

[kenjamin]

Todd,

My present fiberglass battens seem really heavy and I have access to all types of carbon fiber resin injection techniques at the College of Engineering here. I also just sold my land and have a pretty good chunk of money in the bank. Do you have any good links for them there "fancy" battens?

Thanks for your input. I appreciate it.

[Todd Bradshaw]

Since I rarely use that sort of batten these days, I really haven't kept up on which distributor is selling which brand of battens. On the last sails that I built using tapered full battens, I bought Rat Battens (yep, that's the brand name and they were made in South Africa). They worked great, but you're looking at a retail price that can exceed $75 per batten for long ones and they have to be air-freighted in from the distributor if they're too long for UPS. You may need to check with some local, modern sail sailmakers to see what's currently available. You're looking for soft-tip, full battens (not just long leech battens) and their draft needs to be 40%-45% aft. They'll usually come in soft, medium and stiff grades of overall flex. Sometimes they will use soft flex up top and medium down low on boats in that size range, but I think I'd probably go with soft flex all the way up and down. You don't have much round in the roach down low to support and I think I'd opt for whatever has the best chance of being able to give you some draft down there.

[Todd Bradshaw]

I should add, that with enough high-powered equipment it's certainly possible to make your own, but it becomes just one more unpredictable thing that you have to prototype, test, re-build, test again, etc. just to get the battens to flex properly. Seems rather unproductive when the main goal is to take some of the unpredictability out of the equation in an effort to get the sail to set properly.

[kenjamin]

OK Todd, I'll take the present battens out and grind on them some with my little 4&1/2" grinder and try to get some decent taper to them for a better shape out of my main. Thanks very much for your information.

I had Jeff at Sailrite design me a pretty flat draft in the main sail as the afternoon Gulf breezes (St. Marks Lighthouse) really blow but lately I've been sailing the protected waters of my hometown, Matanzas Bay, St. Augustine, Florida. Thankfully, Mr. Oughtred's Caledonia Yawl hull is very efficient and is easily powered by my "newbie" sail sewing attempt. I did recently buy Sailrite's zig zag model and I hope to start on the birdwing mizzen this weekend. It has a few battens but they are not full length. Thanks again.

[Chris Ostlind]

Uh. . . .I don't think it should be optimized to shed the wind. . . .I think it should be optimized to harness the power of the wind in developing lift. . . . .



James,

Just what is your main beef here?

Kenja has stated that the sail and mast are a work in progress, yet you, apparently, want to hold him accountable, as if his study process in all of this is to be summarily dismissed.

I, for one, do not agree with your position. Perhaps there are others who feel the same way. From where I sit, the progress on this design approach has been thoughtful, well managed and it is certainly well built.

You come off like a guy who is at the high point of his career as a rig designer, yet you haven't posted one single thing that would justify that kind of attitude in this discussion. How about laying low while the rig is further explored for all around potential?

When the rig is more fully developed and Kenja is happy with the outcome, you can then step-in with your all-knowing pronouncements... provided that you actually sail the boat in question and give your opinion based on real world experience and not supposition.

Isn't that a fair approach?

Chris O

[Robert L.]

OK, a few unstructured observations from the peanut gallery.

I usually side with James because he does this sort of stuff for a living and tends to take a conservative practical view of things boat related.

I think kenjamin tends to manipulate too many variables at once to gather any actual usable data and it seems that he relies too heavily on his gut feelings without enough background knowledge and experience to back him up.

I myself haven't done any sailing in a long time, and have only helped make sails once or twice. But I have done a lot of sewing with heavy fabrics and tend to agree with Todd that perhaps a lot of the visual problems with the sails may just be due to poor craftsmanship (at least that is what I think he is trying to say).

On the other hand kenjamin has actually built his boat, is sailing it, and doesn't blame others when things don't go as expected. This puts him way ahead of many of us up here, and most of those who live in the bilge.

Go kenjamin

As far as I am concerned if he can get the wrinkles out of the sail and the boat goes up and down wind without oars, and he can get back to the dock without help from the Coast Guard he's doing OK. (even if the rudder is butt-ugly)

One final thought, just to make it more confusing, why does the entire mast need to be stiff? why not an adjustable tip using something along the lines of a two rod guitar neck truss rod, or if you have deep pockets a bimetal strip, shape memory metal etc?(actually the last two are exotic and impractical enough that you could probable get some sort of funding). If you're going to mess with the tried and true do it with enough gee-whizz factor to redirect everybody's attention.

[rbgarr]

I don't understand the theory of the pre-bent, stiff spar in an unrated situation. What advantage is it supposed to offer?

[Robert L.]

I don't understand the theory of the pre-bent, stiff spar in an unrated situation. What advantage is it supposed to offer?

I don't remember all of the discussion but I believe part of the reason was to make it stowable while rowing without everybody having to straddle it. I think it fits the curve of the hull.

[ChaseKenyon]

I don't remember all of the discussion but I believe part of the reason was to make it stowable while rowing without everybody having to straddle it. I think it fits the curve of the hull.


Many of our best common things and advances in technology and science have come about in just such an unintended and round about way. A good example would be the winglets on the flexible rotors of all Kaman and other helicopters. Or the famous failed glue that became 3M stickup notes. Or the failed rotor blade composite that became the Lyrachord composite for Ovation Guitars.

So you go Kenja!!!!!

[rbgarr]

Let's not go overboard, fellas.

[Todd Bradshaw]

In general, I'm enjoying watching the rig develop to whatever conclusion it eventually comes to. I think my biggest gripe with the entire project so far has been the rather constant premature references to marketing it. In the mean time, it hasn't been tested against another boat with the conventional rig, so we really have no idea whether or not it works worth a hoot. That hull is easily driven, as mentioned, and I have yet to see a single photo of it where the sail set could even really be called "decent", so there is a lot of work yet to do before anybody starts singing its praises. We have an unusual cosmetic profile that some folks find attractive, but that's really about all we know.

I don't see anything glaring about the workmanship, but the devil's in the details and ironing them out will be a challenge that will have to take place before an accurate and meaningful performance assessment can be made. It's not that I don't trust people (well, maybe it is) but an awful lot of unusual home-based boat mods tend to be praised by their owners with little more substantial info than "it works great". The question that always comes to mind is "Compared to what?". The standard CY lug yawl rig is simple, efficient and drop-dead gorgeous from a cosmetic profile standpoint. Improving on it in any of those respects is quite a challenge. To date, we can't even say for sure whether properly setting sails with proper draft and entry angles are even possible on this mast, though I assume that they probably should be. We also have no idea how much adjustability those properly-set sails will have, since ideal sail shapes for different conditions can change as fast as you can turn the tiller and change headings.

I do find the project interesting and worth continuing, but before someone starts talking about marketing the concept, I'd like to see it actually work. Until then, I put it in the "interesting and possibly innovative modification" category. Since the original concept was to sail out, stow the rig out of the way for fishing, re-step the mast and sail home, I'm curious, has out-in-open-water raising and lowering of the rig been tried yet? If so, how did it go with that fairly heavy mast? Is that going to be a reasonable option for the typical guy and his wife out for a sail, or are they going to need to buy some sort of custom-molded and autoclaved, big-buck carbon mast to be able to try it?

Admittedly, I really like strange and unusual rigs and the whole concept of tweaking them to see what they can do. I'm lucky, in that much of what I build for my customers falls into that category. It keeps me from getting bored. If I never saw another white, medium aspect, triangular marconi mainsail to be fixed atop a fiberglass box in my life, it wouldn't bother me one bit.

We briefly had another forumite a few years ago from europe who was proposing a different sort of unusual rig. I ended up making a concept drawing for it and always though it looked interesting. Of course, masts don't ever fall down on concept drawings, or roll the boat over due to excessive weight aloft, but I do enjoy seeing what people can come up with. I haven't a clue whether or not he ever tried building such a system, but his concept looked kind of like this. I suspect that it might be horribly top-heavy and that it might be awfully difficult to justify that much mast mass for that amount of sail area, but if nothing else, it goes to show that with the right drawing, you can make just about anything look good on paper. Making it work equally well out on the water is a much bigger challenge.

http://webpages.charter.net/tbradshaw/X2%20copy.jpg

[James McMullen]

Chris, I do see your point that you think that maybe I'm guilty of badgering our Comrade, but I don't think you know the history we share. We were friends on the CY Forum (http://www.mavc2002.com/cyforum/index.php?sid=cc170672e2e1364be225d191141135fd) before we both showed up here, and have been passionately arguing over whether or not it is possible to "improve" Oughtred's genius design since forever.

My "all-knowing pronouncements" as you put it are coming from having owned very similar boats since I built my first one in 1996 with the original sort of rig that Kenjamin substituted his invention for . . . . .14 years is a pretty fair baseline, wouldn't you agree? There are certain aspects of Oughtred's original rig that I find from experience are particularly well suited to handling this kind of open boat, and that are absent in the "birdwing" concept. Since open boat Sail & Oar cruising has been my obsession and my passion for almost two decades now, I think that this forum is an extremely good place for me to air my concerns and questions about an experimental rig for a type of boat with which I am intimately familiar.

Kenjamin's enthusiasm and enjoyment of his experiment are things I very much support, but there have been several times when his enthusiasm for his design has caused him to make statements that have been based on. . . .well, enthusiasm, rather than a more objective assessment. I very much do not think that this design is mature enough, nor as well rounded as the drawn rig for anyone to advocate it to other amateur builders without fair warning.

As far as sailing on Xena, I have been extended a standing invitation by my Comrade to come sailing anytime I am in Florida, just as he is welcome to come sailing any time he happens to get up to the upper left corner of the country. For that matter, if only I had known you then, I would have been delighted to invite you to come for a sail on my old lug-rigged Ness Yawl that time I trailered her out to the Great Salt Lake years ago. I'd be more than happy to argue about sail rigs over a beer in person with all y'all.

[Paul Pless]

ain't this quite the lovefest all of sudden;)

[James McMullen]

Any excuse to drink beer, Paul

[kenjamin]

Hey James, I just sent Chris Ostlind a letter explaining that everything is cool and that I actually enjoy arguing with you. He would understand better if he had gotten a look at all the pages and pages of our "discussion" about my mast and theories on the Crazybird Caledonia Yawl site. I certainly don't want any negative and too personal type of stuff to take over the "discussion" of my mast.

Getting back to good old arguing, I noticed that there was a big "sounds of silence" from you about my little 2 lb. bamboo yard being harmless compared to your big timber yard that would put a serious hurtin' on your head if it fell on you. And don't give me any of that stuff about my rig being hard to strike 'cause it just ain't so. The plastic slugs sliding in the plactic lined luff groove make for a very rapid dropping of the main. There's even a downhaul line to the bamboo yard that runs back to command central near the tiller so I don't even have to get up out of my seat to strike the main.

Also you didn't seem to be able to find fault with my downwind picture. Maybe you noticed how well centered the power of the main was above the hull.

I still think your boat and rig are prettier than mine but I'm working on that too. I'm dishing the oar thingie and replacing it with a more powerful birdwing mizzen. Also the threat of a genoa build is much closer to reality now that I have a girlfriend who wants to help me sew sails this weekend on my new Sailrite machine and table. Hell, when it's all done, I may just pack up everything and drive out there to race you and your lovely Rowan. If I win, you buy the beer.

[James McMullen]

I'll buy you a beer whoever wins, if you truck that crazy thang up here to go sailing, Comrade.

Oh, but by "set or strike the rig" I'm really talking about getting everything down, all spars flat in the boat and rig stowed securely to ride out a nasty tidal rapid under oars, weather a squall, or just get everything down to reduce windage for maximally efficient rowing, not just dropping the mainsail down to rest on its boom. . . .

All the way up to all the way down or the other way around in under four minutes is my average. I can get her stowed down and under oars in ninety seconds if I'm in a real hurry--setting up takes longer though. (Takes a few minutes more to make a neat furl, though, if you're trying to look presentable.) This is one of the most useful, safe and handy features of a lugsail for a small open boat.

http://inlinethumb38.webshots.com/42597/2869347080088484686S600x600Q85.jpg (http://sports.webshots.com/photo/2869347080088484686xLPMnS)

[Robert W. Long]

My wife and I took our newly purchased Caledonia Yawl to Bucks Lake in Nor. Calif. shortly after bringing it home from Illinois and I was totally amazed to see her unstep the main mast and stow it like it was no big thing at all, and this was on the water.

[kenjamin]

Don't have a wife to step my mast for me. Wow! What a luxury!

I do have a fishing buddy who was the catalyst for my birdwing mast invention.

http://www.bodaciousboats.com/XenaFishing.jpg

Look at him sitting there so innocently playing with his cell phone. When, in fact, he can be the most disagreeable, loud, obnoxious, drunken fishing buddy anyone could have nightmares about. He does, however, provide someone I can yell and scream at without any consequences. And we've trained each other over twenty years or so to usually catch fish which is good in a fishing buddy. Notice how the birdwing mast curves completely out of his way. It even tucks up behind him at the bow. He doesn't even know it's there. The pile of lumber you see on the port gunwale are my oars. Xena has two rowing stations and carries four oars and a paddle. The bottom part of the mast does intrude somewhat on my space at the tiller but not enough to keep me from fishing.

I've said all this to say that my mast is already 100% successful at what it was originally designed for. It was only after the first prototype that I came to realize that the design may have (that means maybe) aerodynamic advantages going to windward. It occurred to me that if I built the new and improved boat and the new and improved mast on my second attempt that someone might see the concept and try to patent the idea even though I thought of it. Just imagine how irritating that would be! I found out that I could give the idea to my employer, Florida State University, and they would incur all expenses with getting and defending a patent. So FSU owns 60% of the rights to the design and I have 40% but I figured 40% of something is better than 100% of nothing. The application has already been sent to the U.S. Patent Office a couple of times due to revisions and a new drawing that FSU's patent lawyer came up with. I don't know if anything will ever come of it or not but at least my version of a birdwing mast is well documented.

So in answer to Todd's irritation about my constant talk about the idea's marketability, every inventor wants his idea to go to market. It's that simple. Whether it will or not is pure entertainment for me.

The mast presently does not step as easily as the conventional lug rig but I've had thoughts of a gated mast step that would make it much easier. Presently, I feel the need to beach Xena in order to stabilize the hull for stepping the mast. I don't know if my imagined new mast step would make stepping at sea practical or not but of course, I'd like to find out.

[Robert L.]

The mast presently does not step as easily as the conventional lug rig but I've had thoughts of a gated mast step that would make it much easier. Presently, I feel the need to beach Xena in order to stabilize the hull for stepping the mast. I don't know if my imagined new mast step would make stepping at sea practical or not but of course, I'd like to find out.

OK, so the above image is the first I have seen that gives a good idea of how massive that mast is. Just how much does that thing weigh anyway? There are always easier ways to move and lift awkward and heavy things, just ask any old fat guy (not the soft doughy ones) how he would do it. On the other hand I would think that there has to be a better way to accomplish the task without the mass or too much in the way of exotic materials or technology, given that the initial goal was a mast that would stow neatly in the boat. That would be my first goal (well after figuring out what to do with all the oars when they aren't being used). From a commercial standpoint I think the stowage issue coupled with the interesting, if not traditional, esthetics are more marketable than pure performance for a larger percentage of the market.

[Todd Bradshaw]

I don't know, but if he builds a set of gunwale-curved oars I'll really be impressed. :) That is the biggest freaking mast I've ever seen on a boat that size. The drawback to a smaller diameter is what? It flexes? On a lot of boats that can be used to one's advantage as a prime sail-shaping tool. It does make getting the mast/sail/luff-curve relationship working properly more of a challenge, but nobody ever said the project would be easy.

Keel-stepped with gated partners and an easily removable boom crutch (or in this case, maybe even one built onto one side of the mizzen mast) worked quite well on our trimaran, especially with a small, simple roller on it's top for jockeying the mast into fore and aft position.

[kenjamin]

Nobody said it would be easy. Getting a sail to set correctly along a stiff curved mast is a whole new can of worms which may or may not be worth pursuing. Of course we'll never know until it is tried more than a few times. Didn't Thomas Edison try almost a hundred different filaments in his electric light bulb before he found one acceptable? My premise for a stiff curved mast was so that it could more effectively set head sails without ruining the set of the main. The other benefit is that it is a brute of a mast and while a bit heavy at 42 lbs., it enjoys the fatigue resistance of laminated wood and its shape will shed water as well as it sheds air in the event of a capsize. My mast, in all likelihood will outlive me and my nephews and maybe their kids.


It's all in the perspective. This photo shows the mast doing its thing and we are moving right along here. As I said before, I credit the ease at which the boat moves to Iain Oughtred, not to my sailing rig. If we were going a knot or two faster here, do you think it would make any difference to anyone enjoying the ride? I would probably like it but I doubt anyone else would notice that much.

I had to overbuild the thing because I couldn't afford for a patent pending design to fail. But also remember that most of the weight is in the solid lower portion of the mast (below the boom) and the curved upper portion has three hollowed out tunnels for the halyards (jib and main) and the luff groove (which was once a tunnel but later opened up with circular saws [one cordless for accuracy and one corded for the final opening width]). So there's a lot of air in the way of tunnels in the upper portion of the mast. The jib halyard exits near the top of the mast very close to the axis of rotation of the mast so it can still rotate automatically to favorable angles of attack. At least that's how it seems to me.


http://www.bodaciousboats.com/XenaSails.jpg

[rbgarr]

"My premise for a stiff curved mast was so that it could more effectively set head sails without ruining the set of the main."

What does that mean, head sails ruin the set of the mainsail?

[kenjamin]

The jib pulling on the top of an unstayed mast can affect too much the set of the main. The glue lines on my mast run fore and aft so they resist the jib's efforts to bend the mast forward. Also the curvature of the mast itself seems help resist the power of the jib. At least that's the way I see it happening. Hoisting the jib with the main already up can yield a kick in the pants like when a turbocharger kicks in accelerating a car. Unstayed masts are not supposed to be able to carry headsails well but this mast seems to handle it just fine.

http://www.bodaciousboats.com/XenaSaills2.jpg

[Todd Bradshaw]

"The jib pulling on the top of an unstayed mast can affect too much the set of the main."

Uuuhhh....that's pretty rare. It's usually the unstayed mast affecting the jib by not providing enough jib luff tension (luff sag makes the jib too drafty, among other undesirable things). The main isn't usually bothered much by this unless it's getting backwinded and the slot is closing up and mainsheet tension generally helps reduce the sag in the jib luff, making the jib and the whole sloop-rig concept work better.

It's certainly possible that your mast has different, possibly even better, abilities to resist jib luff sag, but here again, you say "it works great" and I say "compared to what?" Without doing head-to-head trials against the norm or having an awful lot of very expensive computer power and the knowledge of how to use it for this purpose, it's very hard to support many of your conclusions.

[rbgarr]

Jibstay sag isn't necessarily a bad thing. It depends on the cut of the sail. My boat points higher in light winds with it.

[kenjamin]

Todd, it's not like I have been avoiding racing conventionally rigged Caledonia Yawls. I just haven't encountered any and I don't know of any working out of St. Marks Lighthouse, Florida or St. Augustine, Florida's Lighthouse Park, my usual waters. Thanks for correcting me on the problems of setting a headsail on an unstayed mast. All I know is that it seems to move along nicely and everyone aboard seems to have a great time. Is it OK to say that?

I do have the sail kit for what I hope to be a better looking and more powerful birdwing mizzen as well as a large genoa which should step up light air performance somewhat. To be perfectly honest, I probably won't go looking for trouble (racing) until these new sails are sewn and I get used to them. But if I were to encounter a CY sailing in my local waters, you can bet I'll want to see how Xena compares. It's not going to kill me if the other boat is faster. It will just mean I have more work to do.

I also have to redo my daggerboard with a NACA cross section as the one I have now is just rough shaped oak and I'm sure it's a dog compared to what is possible now with templates and such. A racing rudder wouldn't be a bad idea either.

http://www.bodaciousboats.com/packed.jpg

[Chris Ostlind]

Chris, I do see your point that you think that maybe I'm guilty of badgering our Comrade, but I don't think you know the history we share....



James, having no knowledge of your long established, interpersonal haggle, please accept my apology for getting a bit grumpy in my previous post. Looks like I dropped-in on a friendly version of the Hatfields and McCoys and probably should have watched a bit longer.

Now that it's clear, it is a pretty amusing joust you guys have going on.

Chris O

[kenjamin]

Hey Chris,

I'm glad you've got the truer picture of the dueling philosophies of sailing that the two of us have. James likes to follow the master's (Iain Oughtred's) plan and I entertain myself by changing just about everything but Iain seems to find my birdwing sailing rig entertaining (see blue letter on page one of this thread). James did, however, request and receive support from Iain about the dimensions of Rowan's hull which are different than just about anything on the water. James and I, believe it or not, worked together on a project of sailing instructions for the yawl rigged boat a few years back. It was actually James' project but I redrew it and prettied it up some for publication on the Crazybird Caledonia Yawl web site.

I was surprised to find someone coming to my defense in dealing with Comrade James. That was a refreshing change from what I normally encounter from avid sailors. Seems like WoodenBoat forumites as a group are a pretty traditional bunch and most want thier masts to stay fairly straight just like they've always been.

I've built this beast of a mast to quiet my fishing buddy (the straight one was in his way) and have been having a lot of fun finding out what it can do when pressed to its full potential. I'm very curious to see if it can handle the big genoa I'll be building. Time will tell but progress is slow.

Thanks for your interest in the project and surf was up in St. Augustine last weekend, dude.

http://www.bodaciousboats.com/Xena2722sm.jpg