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Thread: Centennial Vs. Scamp?

  1. #1
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    Default Centennial Vs. Scamp?

    So I have been happily following the voyages of various Scamps, but Southern Cross in particular, secure in the knowledge that what ever sort of water or weather Scamp could handle Centennial could handle with ease... then came news of SC being over powered by wind and weather in the wilds of Tierra DelFuego... so now I'm left wondering how well Centennial or a similar design might have fared under similar conditions...?

    the similarities between the boats are remarkable, If one were to cut 2 ft off the bow and 6' off the transom of Centennial the hull voulumes and shapes would be incredibly similar.
    both boats are fairly lightly ballasted light displacement hulls with a generous amount of free board, both craft have short bowsprits that can be used to fly head sails in light airs. Scamp does have the second mast but the simplicity of a sloop rig appeals to me when venturing far from shore and shop, fewer components to fail and fumble with.


    Of course both boats do have differences, most obviously the age of the design, where Centennial was designed 140 years ago by old salts on the coast of New England using a trained eye and generations of blue water knowledge Scamp was designed by a foremost modern small craft designer as a state of the art small adventure craft.

    Centennial does seem to have a few advantages that make me wonder how she might have fared under similar extreme conditions...

    First, a totally enclosed living/below decks area, which if battened down properly should remain moderately dry even in the event of a capsize.

    2nd, significantly heavier hull and ballast carrying ability. the boat I am building will be modified with close to 200 lbs at the bottom of a swing keel which can be locked down for security when sailing off shore or in extreme conditions.

    3 Tabernackled mast designed by "Centennial Johansen" to be lowered easily while at sea allowing the boat to be battened down and reduce windage aloft while riding out extreme weather.

    Decisions, decisions, I have to admit I am keeping an open mind during this build and hope to take any lessons learned by Howard and SC Scamp to heart and apply them to my current build.


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    Default Re: Centennial Vs. Scamp?

    You don't have the option of bringing Centennial ashore, as it she just too big and heavy. That proved to not be a useful feature in Chile, but it may be in other areas. I suspect the tabernacle mast would have been a good thing.

    Your boat probably has superior stability, due to the extra length. If it did capsize , getting it back on its feet would be harder.

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    Default Re: Centennial Vs. Scamp?

    I read that Howard sez the "conditions" , the williwaws that flipped him while anchored under bare poles, could not have been tolerated by any small boat.
    I believe you are mistaken by thinking the sloop has less stuff to break than a ketch. I recon the sloop is more likely to break.
    I think scamp will out tack centenial(tack faster) and point higher.

    Centenial would be better as a life raft survival craft, being, as you say,closed in.I have not sailed on either type of boat so I am just speculating.

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    Default Re: Centennial Vs. Scamp?

    I think a heavy swing keel, even locked down, is a potential weak point. When the boat is really getting slammed around, that much weight has a LOT of inertia. I'd much rather have a fixed keel or no keel at all.

    I doubt any small boat would have handled the conditions Howard faced--at least, not better than Southern Cross, which did apparently survive relatively intact, after all.

    Tom
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    Default Re: Centennial Vs. Scamp?

    Please do remember Southern Cross isn't a stock SCAMP. The "regular" SCAMP has a balanced lug sail with no bow sprit. There are other features of Southern Cross that are modifications Howard made specifically for sailing Below 49 South. I believe there are dicussions on a couple of different threads across forums here, and on the Small Craft Advisor message board.

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    Default Re: Centennial Vs. Scamp?

    The yawl rig on Southern Cross has very low windage with the sails down. Its essentially unstayed, has two running backstays which are held against the mast while not in use, and the jib is set flying so there is no permanent forestay. This is intentional to make the boat less vulnerable to windage and to make her easier to row in calm weather.

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    Default Re: Centennial Vs. Scamp?

    At least a raised mast has some added bouyancy for when you are inverted. Lowering a mast, in conditions that you think needs less windage, would require and VERY substantially built tabernacle and pin, and a fool-proof "one-shot" lowering system, having seen the hole ripped into a deck by a wildly bucking mast. Your locked down and ballasted keel should be more than enough to off-set your short mast. If i thought i needed to lower my mast at sea to be safe.....i would pick another boat design.

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    Default Re: Centennial Vs. Scamp?

    In 50 plus knots everything is windage including bare unstayed poles. I think centennial well ballasted might do better because of its dory hull.
    whatever rocks your boat

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    Default Re: Centennial Vs. Scamp?

    A very good physicist friend of mine once said, "Truth is very much like a doughnut without a hole." At the risk of having pastries hurled at me and getting kicked off the forum, it is possible to design a free-standing, well balanced, self-rotating mast with extremely aerodynamically slick cross sections and an overall profile that is swept back along almost its entire length that is in the airflow. Would this would have prevented a cyclone from ripping Howard off his SCAMP and slamming him somewhere down wind too far to get back to the boat? Probably not, but I think when curved sailboat masts are designed to be more foil-like and less stick-like, things could get very interesting especially under bare pole high wind conditions.
    Last edited by kenjamin; 03-17-2017 at 08:13 AM.

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    Default Re: Centennial Vs. Scamp?

    k when sailboat masts are designed to be more foil-like and less stick-like, things could get very interesting especially under bare pole high wind conditions.
    Lots of multihulls have been built with a huge variety of foil-shaped masts. Without exception, in all my reading, they're a nightmare in extreme conditions. Instead of just creating drag, the boat is constantly being driven left and right by the mast. The foil becomes a motor that you can't shut down. Even on a moderate day at anchor, such boats don't lie still. There's nothing better than being able to drop the mast, but of course as the boat gets bigger, this becomes more difficult.
    -Dave

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by WI-Tom View Post
    I think a heavy swing keel, even locked down, is a potential weak point. When the boat is really getting slammed around, that much weight has a LOT of inertia. I'd much rather have a fixed keel or no keel at all.

    I doubt any small boat would have handled the conditions Howard faced--at least, not better than Southern Cross, which did apparently survive relatively intact, after all.

    Tom

    ohh interesting take on the ballast swing keel... so would you be advocating hauling up the centerboard in extreme conditions to reduce the lever arm of lead ballast? i think I will have to see how the boat is responding to conditions but keep this option in mind as a last resort sort of maneuver.


    I have also considered the posability of carrying two deflated Gloucester balls which with the onset of bad weather could be inflated and lashed on deck at the bow and stern creating two flotation chambers high on the hull which would help the the hull right side up in the event of a capsize.

    there are a number of other small craft which we sail and build that may find themselves in a similar extreme wind situation as SC Scamp, though many of us would rather not consider the worst case scenario I wonder how other sailors would handle similar situations...


    Last edited by Daniel Noyes; 03-17-2017 at 08:46 AM.

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    Default Re: Centennial Vs. Scamp?

    Dave, it makes a big difference when the overall shape of the mast is more swept back along its entire length. The length along the airflow allows the mast to quickly adjust itself to the absolute lowest aerodynamic drag position where it creates very little to no lift in any direction. Having the such a mast rotate within a polyethylene bushing while standing on a polyethylene bushing makes a great deal of difference too. It's a bit unreasonable to try to assign handling characteristics of what are basically stayed straight masts to a well-curved, free standing balanced mast operating on low-friction bearings and the only downward force on those bearings is the weight of the mast.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Paul G. View Post
    In 50 plus knots everything is windage including bare unstayed poles. I think centennial well ballasted might do better because of its dory hull.
    I'm interested to hear Howards take on this subject and see some of his video, I would think that Centennial with her sharp bow might have a better time of working to windward against a short steep sea like the 9'ers Howard encountered, but that may not be the case.

    I am encouraged that when the mast is lowered and lashed in place with the rest of the rig the center of effort on the hull should be rather far aft... in effect the lowered mast and sails may function like a mizzen mast, weathercocking the hull into the prevailing winds...



    apparently it was a mountaious breaking sea which doubled the height of Centennials mast and sent Johansen over the side 20+ miles off the Cornish coast, this was what Johansen called the worst storm he had see during his time at sea... that means something coming from a Gloucester schooner captain with 30+ years on the banks at all times of year.

    fyi a breaking sea at double Centennials mast height would be looking at a breaking wall of water somewhere north of 30' in height!
    Last edited by Daniel Noyes; 03-17-2017 at 08:57 AM.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Daniel Noyes View Post
    I would think that Centennial with her sharp bow might have a better time of working to windward against a short steep sea like the 9'ers Howard encountered, but that may not be the case.
    Sharp stem but a flat bottom......

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Daniel Noyes View Post
    apparently it was a mountaious breaking sea which doubled the height of Centennials mast and sent Johansen over the side 20+ miles off the Cornish coast, this was what Johansen called the worst storm he had see during his time at sea... that means something coming from a Gloucester schooner captain with 30+ years on the banks at all times of year.

    fyi a breaking sea at double Centennials mast height would be looking at a breaking wall of water somewhere north of 30' in height!
    There is a reason those of us with experience of sailing around Cornish waters may have a different idea of what is considered "sea worthy", given the local conditions.......

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Daniel Noyes View Post
    ohh interesting take on the ballast swing keel... so would you be advocating hauling up the centerboard in extreme conditions to reduce the lever arm of lead ballast? i think I will have to see how the boat is responding to conditions but keep this option in mind as a last resort sort of maneuver.
    I guess I'm really just a hater of swing keels altogether--I don't like the idea of a heavy weight that's hanging below, secured only by a bolt/pin rather than the structure of an integral keel. Any slop at all (i.e. in any kind of waves or chop) seems dangerous. But I guess that's what you're going with in Centennial, eh?

    I'm also biased by past experience, having a cable on a 700-lb swing keel break in a narrow entrance channel, setting the keel firmly down into the mud. Took a long time to swim a line under and winch the keel back up. I much prefer unweighted or lightly weighted boards. If it's a ballast keel, I want it fixed, not swinging and bashing around.

    Tom
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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by kenjamin View Post
    Dave, it makes a big difference when the overall shape of the mast is more swept back along its entire length. The length along the airflow allows the mast to quickly adjust itself to the absolute lowest aerodynamic drag position where it creates very little to no lift in any direction. Having the such a mast rotate within a polyethylene bushing while standing on a polyethylene bushing makes a great deal of difference too. It's a bit unreasonable to try to assign handling characteristics of what are basically stayed straight masts to a well-curved, free standing balanced mast operating on low-friction bearings and the only downward force on those bearings is the weight of the mast.
    Ken, if I recall correctly, many of the big multi masts are sitting in very, very impressive and expensive roller bearings of about 10 inches diameter. Furthermore, most of the mast is behind the axis of rotation, which is about 30% back from the leading edge at the base and in front of the leading edge at the hounds. The mast therefore "weathercocks" pretty easily.

    Even the mast on a standard off-the-beach performance racing cat will flick back and forth from one rotation to another quite easily. And even a perfectly friction-free rotation system will not solve the problem of the mast developing lift, because any mast has inertia along its vertical axis. To overcome that inertia, even with no friction at all, will require the wind to exert force on the mast. That force on a wing-shaped object is likely to, and perhaps must, create lift and power.

    Secondly, all else being equal if a mast has to handle normal sailing structural loads then a wingmast is normally a larger and heavier object than a round or pear-shaped mast and therefore the extra bulk and weight have to be allowed for in any comparison. That's not even allowing for all the other significant issues of a wingmast in a small monohull, such as the inferior gust response.
    Last edited by Chris249; 03-17-2017 at 07:03 PM.

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    Default Re: Centennial Vs. Scamp?

    Re dropping the mast; the issue is that doing so will reduce the moment of inertia and make the boat (according to some tests) more likely to roll. It will also have a very fast motion which is an issue in itself.

    Probably not a big issue in the original Centennial, which would have had a higher centre of gravity due to the lack of a deep ballasted keel.

    Tom, are there many instances of properly built swing keels detaching in storms? I can't recall hearing about it.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Chris249 View Post
    Ken, where is your proof that the multihull masts don't rotate freely? If I recall correctly, some of them are sitting in very, very impressive and expensive roller bearings of about 10 inches diameter. Furthermore, most of the mast is behind the axis of rotation, which is about 30% back from the leading edge at the base and in front of the leading edge at the hounds.
    Not so long ago, a friend of mine, a very competent engineer, built a good sized multihull with a wing mast. Much attention was paid to the issue of the mast mount bearings and freedom of rotation. Although it sailed well when fully crewed it was a disaster, in the end the marina banned it due to its behaviour when in its berth, it very nearly got capsized when sailing in a storm when the crew couldnt "reef" the mast itself, and in the end they changed the rig back to a D section carbon spar.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by john welsford View Post
    Not so long ago, a friend of mine, a very competent engineer, built a good sized multihull with a wing mast. Much attention was paid to the issue of the mast mount bearings and freedom of rotation. Although it sailed well when fully crewed it was a disaster, in the end the marina banned it due to its behaviour when in its berth, it very nearly got capsized when sailing in a storm when the crew couldnt "reef" the mast itself, and in the end they changed the rig back to a D section carbon spar.

    John Welsford
    --- I would like to know how Randy Smyth managed his wing mast on his custom "Sizzors" trimaran; this 18 foot ultra-light trimaran was built for the Everglades Challenge but this is the first year on a wing-mast. Previous versions of the boat had soft sails and the rig could come down for bridges and such (low branches in the Everglades channels?) and go back up again relatively conveniently. His new huge wingmast didn't seem as though it could be reefed (he did have a leech-mounted soft sail/square-top that somehow attached for light air). Photos at the start beach suggested he needed help raising that wing mast, so maybe you can now pick a course that avoids the previous low-bridge filters? Even so, what a ride it must have been with that unreefable wing in this year's tempestuous EC. -- Wade

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    Default Centennial Vs. Scamp?

    Much of the confusion regarding my birdwing mast is my own fault. When I set sail with my birdwing mast on my Caledonia Yawl back in 2007, the overall profile appeared like a bird's wing so I nick-named it the birdwing mast. However it is not a "wing mast" at all. It is much more like a conventional mast only with a sickle shape that allows for a straight section with a round cross section to rotate within the mast step while the curved part (exposed to the air flow) presents curvature along its entire length. Once you drop the sail on my birdwing mast design, there is not much left that the wind can act upon. My latest prototype is more like a very curved blade on a sword rather than having much thickness for wind resistance. And even though quite thin for a mast, it still has a very slick aerodynamic cross section. What makes it respond quickly and quietly to changes to wind direction is its swept back shape, low overall mass, super slick aerodynamic cross sections, all mounted to the boat with very slick polyethylene bushings. The sickle shape gives it a balanced system of rotation and much greater length along the airflow. Anyone who thinks it operates just like a rotating stayed mast on a multi-hull is just plain wrong. The birdwing mast is a whole new kind of animal. That is why the design was granted a U.S. patent in June of 2014 (patent #8,739,720).

    The weirdest thing about the birdwing mast under bare pole is how sensitive it is to light air and how quiet it is in heavy air. There are no lines that contact the mast along its length. The main halyard can be left sort of lose as it travels down from the sheave at the top of the mast but because of the mast's curvature, it never has a chance of hitting the side of the mast - the mast curves away from the halyard line so with no contact, no noise and no vibration. You have to experience a quiet bare pole to appreciate it, or so it seems.

    I was there at the start of the Everglades Challenge this year and I witnessed the wing mast of Scissors thrashing about somewhat in response to the gusty changing wind. It looked very efficiently shaped but almost too powerful a shape with no way of turning it off that I could see.

    As for Centennial vs. SCAMP, I would take either one of them if they each had enough positive flotation in them so that I would always be floating above the sharks no matter what else happens. The SCAMP's lighter weight makes it easier to drag up on a beach and turn over for repairs (like Howard did) and it's pram bow is pretty much broach-proof.


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    Last edited by kenjamin; 03-17-2017 at 07:48 PM.

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    Default Centennial Vs. Scamp?

    The Centennial with its finer bow, more length, and more mass should make better headway in choppy confused conditions. Neither boat is self-righting (right?) which would worry the heck out of me in anything close to conditions that Howard faced. That Howard Rice is an adventurous soul and good on him I say but never my cup of tea. I got more than I wanted to handle in the Texas 200.

    For my next build I've been leaning towards Captain Short's Yangtze Pelican design that has enough high buoyancy and low ballast to be as self-righting as a good rubber ducky. With it's small center cockpit, you can be out of the weather when rowing. And even with the cockpit fully swamped, the boat has enough reserve buoyancy to keep right on sailing under storm jib and reefed mizzen after striking the main. When the center cockpit takes on water, the boat automatically honkers down with less freeboard and therefore less wind resistance so boat is then less affected by the wind with less of the boat exposed to it. With its design a wave breaking over the gunwale can actually be a good thing automatically adding more water ballast, lowering freeboard, and adding more stability. Captain Short wrote that a Great Pelican could sail happily along half full of water but even with the cockpit fully swamped the similar sized Yangtze Pelican is only 1/6 full of water. My goal for the boat is to figure out how to make that 1/6 amount even less when swamped, much like a boat designed for ocean rowing.


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    Last edited by kenjamin; 03-17-2017 at 08:15 PM.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by skaraborgcraft View Post
    There is a reason those of us with experience of sailing around Cornish waters may have a different idea of what is considered "sea worthy", given the local conditions.......
    +1
    Johansen knew enough as a Gloucesterman to give the Flemish Cap a wide berth but got pooped just miles from his final destination! apparently the local Cornish fishermen were astonished by his tiny light boat, when Johansen told them that these "Banks Dories" small open boats were used 100+ miles off shore in the cod fishery they said that the type of sea that flipped Johansons Centennial was famous for sending local smacks to the bottom with all hands!

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    Default Re: Centennial Vs. Scamp?

    Claims such as "low overall mass" about the Birdwing are extremely arguable when compared to other wing masts. The 30ft A Class, F16 and F18 masts weigh from less than 20lb to 33lb or more - that's a much lower overall mass for a much bigger mast than the earlier Birdwing, and the cat masts are very, very highly stressed. The NS14 wing mast weighs just 7-11lb.

    Many other wing mast creators also tried to create "super slick aerodynamic shapes" and optimise "length along the airflow" and pivoting devices. Many of them are vastly experienced and qualified in the field. It is therefore very hard to see that the birdwing will have any advantage in that area. No evidence that plastic bushes allow for easier pivoting than a small metal or carbon pin, for example, has been produced.

    Despite many years of high-budget development from many brilliant people, wing masts still exhibit significant issues in strong winds. Maybe any claims to the contrary should be quantified, or at least subject to detailed comparison with the highly-developed wingmasts used in NS14s, Tasars, A Class cats, F18 cats, ORMA 60s, etc? Stories such as the one that John related are too common for it to be assumed that the people who created those wingmasts stuffed it up.
    Last edited by Chris249; 03-17-2017 at 09:02 PM.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Chris249 View Post
    Re dropping the mast; the issue is that doing so will reduce the moment of inertia and make the boat (according to some tests) more likely to roll. It will also have a very fast motion which is an issue in itself.

    Probably not a big issue in the original Centennial, which would have had a higher centre of gravity due to the lack of a deep ballasted keel.

    Tom, are there many instances of properly built swing keels detaching in storms? I can't recall hearing about it.
    hmmm, interesting
    I think the reasoning behing Johansens design was his experiences as a dory fisherman, tradition had it that if you were to lay in the bottom of a banks dory it could not be flipped regardless of the violence of the seas, probably a kernel of truth to the tale, and possibly those who were flipped never made it back to tell the story.

    By lowering the mast, lashing the rig to the deck and laying in his berth on the floor of Centennial Johanson was getting his weight as low as possible and possibly also preserving his boats rig from dismasting if he was rolled.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by kenjamin View Post
    The Centennial with its finer bow, more length, and more mass should make better headway in choppy confused conditions. Neither boat is self-righting (right?) which would worry the heck out of me in anything close to conditions that Howard faced. That Howard Rice is an adventurous soul and good on him I say but never my cup of tea. I got more than I wanted to handle in the Texas 200.

    For my next build I've been leaning towards Captain Short's Yangtze Pelican design that has enough high buoyancy and low ballast to be as self-righting as a good rubber ducky. With it's small center cockpit, you can be out of the weather when rowing. And even with the cockpit fully swamped, the boat has enough reserve buoyancy to keep right on sailing under storm jib and reefed mizzen after striking the main. When the center cockpit takes on water, the boat automatically honkers down with less freeboard and therefore less wind resistance so boat is then less affected by the wind with less of the boat exposed to it. With its design a wave breaking over the gunwale can actually be a good thing automatically adding more water ballast, lowering freeboard, and adding more stability. Captain Short wrote that a Great Pelican could sail happily along half full of water but even with the cockpit fully swamped the similar sized Yangtze Pelican is only 1/6 full of water. My goal for the boat is to figure out how to make that 1/6 amount even less when swamped, much like a boat designed for ocean rowing.


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    the original Centennial was not self righting... something I am aiming to fix with the modified 200 lb centerboard/swing keel... are many/any of our sail and oar craft self righting? none come to my mind.

    sounds like the Yangtzee Pelican is using some ultra primative form of water ballast... I would think a flooded cockpit could get pretty uncomfortable/cold for the sailors and make entering/exiting the cabin through the hatch difficult, there must be cockpit drains right?

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    Default Re: Centennial Vs. Scamp?

    Reading about Southern Cross I was wondering about the feasibility of designing a boat to 'half sink' in order to survive heavy seas. I was thinking fully enclosed with a valved snorkel for breathing air. Flood to down low and ride it out, pump it out when the sun returns. Not pleasant but done right perhaps more survivable than bobbing on top. Sounds like the Pelican was designed to do similar. Going to half sink brings you, in your head at least, closer to full sink doesn't make it an emotionally appealing design feature.
    Quote Originally Posted by kenjamin View Post
    The Centennial with its finer bow, more length, and more mass should make better headway in choppy confused conditions. Neither boat is self-righting (right?) which would worry the heck out of me in anything close to conditions that Howard faced. That Howard Rice is an adventurous soul and good on him I say but never my cup of tea. I got more than I wanted to handle in the Texas 200.

    For my next build I've been leaning towards Captain Short's Yangtze Pelican design that has enough high buoyancy and low ballast to be as self-righting as a good rubber ducky. With it's small center cockpit, you can be out of the weather when rowing. And even with the cockpit fully swamped, the boat has enough reserve buoyancy to keep right on sailing under storm jib and reefed mizzen after striking the main. When the center cockpit takes on water, the boat automatically honkers down with less freeboard and therefore less wind resistance so boat is then less affected by the wind with less of the boat exposed to it. With its design a wave breaking over the gunwale can actually be a good thing automatically adding more water ballast, lowering freeboard, and adding more stability. Captain Short wrote that a Great Pelican could sail happily along half full of water but even with the cockpit fully swamped the similar sized Yangtze Pelican is only 1/6 full of water. My goal for the boat is to figure out how to make that 1/6 amount even less when swamped, much like a boat designed for ocean rowing.


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    Default

    In my version of the Yangtze Pelican the helm is positioned a little higher and a notch aft of the center cockpit so the helmsperson, at least, will not even get their feet wet when the cockpit floods. I plan on using two open top off-set centerboard cases with each using a removable centerboard cartridge. The cockpit will drain through the open tops of the board cases long before the boat runs out of buoyancy and also long before the cockpit has a chance of completely flooding to the gunwales.


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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by sailnstink View Post
    Reading about Southern Cross I was wondering about the feasibility of designing a boat to 'half sink' in order to survive heavy seas. I was thinking fully enclosed with a valved snorkel for breathing air. Flood to down low and ride it out, pump it out when the sun returns. Not pleasant but done right perhaps more survivable than bobbing on top. Sounds like the Pelican was designed to do similar. Going to half sink brings you, in your head at least, closer to full sink doesn't make it an emotionally appealing design feature.
    Wouldn't that lead to huge problems with the notorious free surface effect and its very bad effect on stability, as demonstrated with Herald of Free Enterprise and other tragedies? It also means that the boat has to be strong enough structurally to handle a lot of extra weight, and probably leads to a bad case of hypothermia for the crew. Why exactly would it be safer than bobbing on top?
    Last edited by Chris249; 03-18-2017 at 05:04 AM.

  30. #30
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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Daniel Noyes View Post
    the original Centennial was not self righting... something I am aiming to fix with the modified 200 lb centerboard/swing keel... are many/any of our sail and oar craft self righting? none come to my mind.
    The lack of self righting in the original is probably the reason she needed to have the mast dropped, and also the reason that she wouldn't snap-roll viciously as self-righting yachts after they have lost their mast and therefore reduced their moment of inertia.

  31. #31
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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by sailnstink View Post
    Reading about Southern Cross I was wondering about the feasibility of designing a boat to 'half sink' in order to survive heavy seas. I was thinking fully enclosed with a valved snorkel for breathing air. Flood to down low and ride it out, pump it out when the sun returns. Not pleasant but done right perhaps more survivable than bobbing on top. Sounds like the Pelican was designed to do similar. Going to half sink brings you, in your head at least, closer to full sink doesn't make it an emotionally appealing design feature.
    Sailnstink,

    The Yangtze Pelican would not need you to be enclosed underwater which would scare the heck out of me. It's center cockpit has no roof except for a rain fly or a removable bamboo sunshade so you would not be enclosed except you would be shielded from the weather by both the forward cabin and the aft cabin and any side curtains you might want to use. Rather than steal any of Daniel's thunder in regards to Centennial, I'll start my own thread about the birdwing Yangtze Pelican. Hopefully Chris will show up at the Yangtze thread so we can discuss how surely the birdwing mast can not possibly work well because an early prototype was heavy and the construction of birdwing masts is decidedly low budget and low tech and I look forward to that.

  32. #32
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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by kenjamin View Post
    Sailnstink,

    The Yangtze Pelican would not need you to be enclosed underwater which would scare the heck out of me. It's center cockpit has no roof except for a rain fly or a removable bamboo sunshade so you would not be enclosed except you would be shielded from the weather by both the forward cabin and the aft cabin and any side curtains you might want to use. Rather than steal any of Daniel's thunder in regards to Centennial, I'll start my own thread about the birdwing Yangtze Pelican. Hopefully Chris will show up at the Yangtze thread so we can discuss how surely the birdwing mast can not possibly work well because an early prototype was heavy and the construction of birdwing masts is decidedly low budget and low tech and I look forward to that.
    you blokes are well on your way to reinventing water ballast! ... now just add some baffles and a top panel to the center cockpit to eliminate the free surface effect and your done

  33. #33
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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Chris249 View Post
    The lack of self righting in the original is probably the reason she needed to have the mast dropped, and also the reason that she wouldn't snap-roll viciously as self-righting yachts after they have lost their mast and therefore reduced their moment of inertia.
    the banks dory hull has an interesting stability curve, very little initial stability and a large amount of reserve once the rail hits the watter, this makes the boats ideal for rowing in a quartering sea, as the rower ballancing with oars out can keep the hull fairly level for rowing but has the reserve saftey factor of the stability if knocked down by a wave or pulling a big fish aboard... this may be a similar stability curve to some ballasted yachts which are tender at first then stiffen up when layed over... I have heard the Herresshoff Marco Polo design described this way...

    thankfully the centerboard is a alterable aspect of the hull... If I find the weighted board unsatisfactory for some reason I can always build a simple wood one and put the led ballast in the hull... though now that I mention it it certainly is tempting to just build the wood board and ballast the hull, then if that proves unsatisfactory in a roll over drill put the ballast in the board... hmmmmmmm

    you guys are making me think too much!

  34. #34
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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by kenjamin View Post
    Sailnstink,

    The Yangtze Pelican would not need you to be enclosed underwater which would scare the heck out of me. It's center cockpit has no roof except for a rain fly or a removable bamboo sunshade so you would not be enclosed except you would be shielded from the weather by both the forward cabin and the aft cabin and any side curtains you might want to use. Rather than steal any of Daniel's thunder in regards to Centennial, I'll start my own thread about the birdwing Yangtze Pelican. Hopefully Chris will show up at the Yangtze thread so we can discuss how surely the birdwing mast can not possibly work well because an early prototype was heavy and the construction of birdwing masts is decidedly low budget and low tech and I look forward to that.
    do as you wish Ken but this thread was by no means meant to be Centennial only... though the title is a little narrow, I'm interested to hear how any small adventure craft might claim to handle the conditions that brought Howard to grief.

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    Default Re: Centennial Vs. Scamp?

    Quote Originally Posted by Daniel Noyes View Post
    do as you wish Ken but this thread was by no means meant to be Centennial only... though the title is a little narrow, I'm interested to hear how any small adventure craft might claim to handle the conditions that brought Howard to grief.
    I don't think there is anything that could handle the multiple whirlwinds that Howard caught. You'd need something with great stability and no windage. John did what he could to design a rig with as little windage as possible under barepoles, but I have seen thundersqualls rolling through a fleet of centerboarders, even big ones like Lightnings, and capsize boats with the rigs down, centerboard down and crew in the bottom of the boat. When Hurricane Bob came through years ago I did a controlled experiment to see if I could paddle into it in a confined no sea running space ( just enough fetch for whitecaps) To my surprise I did, but I was blown over even with a brace when I had the wind broadside turning around. I could not roll up into the wind. For those thinking about Centennial, Harpo and Samuelson with no windage were rolled by a big sea. Where you would might end up is with a ballasted liferaft. And with the kelp beds in that area, pretty much anything that stuck down would have created a problem.
    Ben Fuller
    Ran Tan, Liten Kuhling, Vernon Langille, Josef W., Merry Mouth, Imp, Macavity and a quiver of unamed 'yaks.
    "Bound fast is boatless man."

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