Design Challenge: Trapwing-"on-deck" ballast-12'-22'

Discussion in 'Sailboats' started by Doug Lord, Oct 7, 2009.

  1. CT 249
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    CT 249 Senior Member

    I think the main point, Timothy, is that it's easy to think of ideas that may not succeed; that's why some of us have problems with complicated concepts that have little relationship to what has proven to work. Many of the biggest recent advances in small boat design come from simplifying things and making them easier to handle, not by adding something more to do when you're going into a mark at 25 knots and a short 3 foot chop.

    It's not hard to think up wild-ish ideas. For example, instead of having ballast suspended close to the water to windward, why not hang it high in the air on huge arms projecting above the hull? The arms and ballast pod would give you a convenient point from which you could pump the whole rig, windsurfer-style.

    And the rig could be a double-surface foil, with helium or hydrogen insidel; actually not, just have black film and you'll create a lot of hot air inside the sail. That could create lift, and the excess air could blast into a tube under the hull and create a low-resistance bed of bubbles for the hull. Oh, and the hot air could also be used to lift a kite for downwind sailing.

    And you could have (if you wanted) a universal joint on the rig and ballast-pod arms. That would allow you to capsize the hull while sailing like a windsurfer. So with the right shape, you could have a slender cat-like displacement hull at low speeds, and then you could turn it 90 degrees around the horizontal axis and bang! - a flat planing hull!

    Of course, the engine power (or solar cells) would allow you to pump the rig.
    Hey, why not make one 700 feet long!

    There you go - a completely impractical idea, in the time it took me to type it. Impractical ideas are easy to dream up. The solid gold ideas are the practical ones, and when you get to really fast craft, the good ideas are almost all simple because no one has the reaction time to handle something overly complex.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    ================
    Timothy, thanks for your post-very interesting. Check out the Speed Dream thread if you haven't already-Vlad Murnikov is considering using a foil very similar to DSS.
    My personal opinion is that one hell of a lot of lift can be generated by a DSS-type foil and that may preclude any requirement for ballast.
    The trapwing,however, extends the ballast quite a ways to weather-much further than the center of lift on a "normal" DSS foil but there is always the possibility that some combination of the two could work-the way you illustrated it is a possibility! The vertical height of the slot in the side of the hull seems like it would have to be fairly high-have you got a solution for that? Another consideration is that whatever solution is used the boat will probably still need some amount of ballast that can be used to right the boat-on the "standard" configuration of the Trapwing that ballast mainly just sits there but a "turbo" version of a large boat using the Trapwing concept could have a 110 degree canting keel to remedy that and make all the ballast on board pay for itself. Of course, bouyancy from the wing helps ensure the righting characteristics.
    Don't be too quick to dismiss your own idea!
    Timothy-thanks again and good thinking -keep it up...check out the two threads below if you haven't already:

    http://www.boatdesign.net/forums/sailboats/flying-canting-keel-extraordinary-innovation-30806.html

    http://www.boatdesign.net/forums/sailboats/monohull-speed-speed-dream-vlad-murnikov-30880.html
     
  3. Cheesy
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    Cheesy Senior Member

  4. Doug Lord
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    Doug Lord Flight Ready

  5. Cheesy
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    Cheesy Senior Member

    Just interested in the hull shape and any more details of it, you are good at finding these things out. The silver fern in the back is an NZ thing so I thought it might of been here, apparantly in Oz....
     
  6. Doug Lord
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    Doug Lord Flight Ready

    I've written Hugh Welbourn for details and pictures. If he sends them I'll start a thread on the boat-looks like an exciting design....
     
  7. Paul B

    Paul B Previous Member

    There was a write up in Tha Daily Sail last week.
     
  8. Doug Lord
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    Doug Lord Flight Ready

    Trapwing Proto / assisted electronics

    Here is an interesting product by the builders of the Martin 16-a self-contained electrical steering and sheeting system:

    http://www.martin16.com/resources/autobrochure.pdf

    Whats really cool is that these are proven electronic systems for use in a marine sailing environment and definitely adaptable to the Trapwing.
    Great stuff!
     
  9. Timothy
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    Timothy Senior Member

    I made a couple of sketches attempting to compare the righting moments of a catamaran , a canting keeler and Doug's Trapwing modified to have a lifting foil to leeward instead of the float which while still providing lift allows for greater travel of the ballast if the system is to be confined to the hull when not deployed. I also canted the ruder and dagger board of the trapwing to leeward in the illustration rather than have two rudders as on the canter. It would seem that a mono hull of equal displacement and whetted surface fitted with the the Trapwing could be built that would equal the righting moment of a cat with a modest beam to length ratio. Of course the trapwing would require constant adjustment as it would be like sailing a cat while constantly flying a hull. What was more interesting to me is that it would appear that a trapwing of equal length and the same cantilever provides more leverage than the canter And so could be built with less ballast for the same RM ,and thus would require less power to move it faster. In the end What I have illustrated is perhaps an unnecessarily complicated weight to leeward proa with lift to leeward. A trimaran? It is impossible to make any valid conclusions based on a couple of doodles but maybe I can elicit some critical response that might advance the discussion.
     

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  10. Doug Lord
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    Doug Lord Flight Ready

    ====================
    Very interesting ,Timothy! My only concern is that the windward extension of the ballast on your system may impact waves too much. What do you think?
    On my "60' Moth" the combination of 110 degree canting keel and sliding water ballast give tremendous RM with the boat likely to be faster than an ORMA tri flying 70% of the weight on a single foil. If you haven't read Hough's analysis there do so.

    http://www.boatdesign.net/forums/sa...ing-monofoiler-design-discussion-15143-7.html post 104
     
  11. bistros

    bistros Previous Member

    Sitting here while it's raining outside and the temperature is around 50 degrees F. I'm going out to the garage to work on Thomas' boat in a few minutes and I feel sad about much of what goes on here.

    Why sad?

    Because many of the "discussions" and designs here on Boatdesign.net are pure daydreams that will never get built, never get tried and never succeed or fail. Ideas get enthusiastically promoted, discussed to death and resuscitated more often than a CPR dummy in first aid training. It's more sad because the idea's promoters talks about their day dreams like they are real boats - saying they are faster than other real boats. An idea isn't faster than a rubber duck in a bathtub.

    It's sad, because it seems a lot of people would rather argue about the merits and features of fantasy daydreams than actually build stuff. One hour out building stuff and solving real problems is worth a thousand hours of time on the Internet.

    Have fun clicking your mouse - I'm going to work on a boat. I feel sorry for people who can't get out in the shop and build things.

    --
    Bill
     
  12. Timothy
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    Timothy Senior Member

    You don't have to feel sorry for me Bistros .I am really quite happy sitting on my porch here in Thailand contemplating my latest creation. He is far from perfect but considering the low technology approach , materials used ,and the questionable credentials of both the builder and the designer , I am satisfied with the result. It took me almost sixty years fooling around with the process and in the end success was both unexpected and accidental. When his mother gets back from the market I shall go windsurfing and later on I will probably sit around with my friends ,who try and make a living building boats, dreaming up weird and maybe not so wonderful ideas for sailing machines. In about another month I will return for six months as I have for the last 32 years to live aboard , sail and tinker with my Freedom 40 cat ketch ,(soon to be a cat yawl if I canot be persuaded otherwise) ,purchased as the result of a dream I had more than forty years ago while visiting some hippy freinds, who were squating on an island in the Bahamas using materials salvaged from the wreck of thier dream an old even at that time staysail schooner. I must admit I do spend a lot more time on the computer than my new wife finds acceptable but then again it is the most facinating machine, and as I never was a television person (did not have one as a child and lived most of my adult life either at anchor or at a cottage where their was no reception) I can,t help myself. The computer was made for us dreamers. Back to movable thwart ship ballast. I do not see your objection to examining the posibilities of using new ways to use what is the oldest method of obtaining stability under sail since we hoisted a straw mat or an animal skin . For that manner why is it all right to use collapsing foils for power turning foils for directional control and retractable foils for windward lift and not to at least look at ways that lifting foils could aid in stability. I am not personally interested in using movable ballast for speed. If I want to go fast I get my thrills from my all out race windsurfer which is of couse is totaly dependent on movable ballast ,me. My interest is in combining shallow draft and a high aspect sail on a monohull. Doug's proposal for the trapwing got me thinking about over thirty years ago when I used to sail to Georgetown in the Bahamas to watch the native fishing schooners sail in the annual regatta. Because the waters of the Bahamas are shallow these boats could not draw more than four or five feet . It was quite a sight to watch for or five of the crew perched on 20 ft planks extended to windward jump off and swim to shore on the downwind homeward leg . Log canoes still use the planks but I believe the crew stay on board through out the race. Well the winds up my wife is back and I am off to sail.
     

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  13. bistros

    bistros Previous Member

    Timothy:

    My objection was not directed towards you, or anyone else who actually sails or actually builds things.

    My problems was with people who substitute reality with their own fantasies. This "Trapwing" discussion has been going on for many years. Much like the fantasy 60' Moth and many other dreamy topics that do not exist in the real world.

    To the promoter of these concepts, the "ideas" are as real as death and taxes. In their mind, these boats are already built and proven - because of the "numbers". To me, they are a waste of time and bandwidth unless they actually get built and tried. It doesn't matter to me if they succeed or fail - I'd rather see the ideas succeed, but talking online about the ideas endlessly is pointless.

    I think this is a great forum to bring up NEW ideas, but an annoying place to endlessly bring up the same old ideas time and time again.

    I just want to scream, shut up already and built it! But if long history on this forum is an accurate predictor of the future, in three years we'll still be hearing about a great new idea called the "Trapwing" and a 60' Moth.

    --
    Bill
     
  14. Munter
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    Munter Amateur

    Doug - other than deciding the length (or having it decided for you by the availability of a hull) have you actually made any progress?
     

  15. Doug Lord
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    Doug Lord Flight Ready

    ===============
    Yes, quite a bit.
     
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