Trapwing 14-High Performance 14' Keelboat(SDB)-Final Design Conception
This concept has fascinated me for well over a year.You can find the original discussion starting on page 3 from it's earliest inception here:
Address:16' Keel boat-high performance
The idea is to have a "sit in" keel boat with loads of power-in a completely different class than the few other "sit in" monohulls currently available. People with handicaps would no longer be deprived of high speed small boat experience and yet would have a self righting boat; able bodied sailors could ditch the keel and sail even faster but w/o having to hike out or use a trapeze.The Trapwing with it's sliding ballast, buoyancy pods and ease of control would allow the boat to develop large amounts of righting moment while the ballasted daggerboard would fit in a molded "V" trunk and cant up to 20° upwind as the whole Trapwing moves side to side. Thats the basic idea but this 14 is a little different.
First, this particular boat is going to be my personal boat. The design is such that most of the hardware, foils(a new set will also be available from day one) and even the mast from my 16 foot foiler will be pressed into service to get this thing going as soon as practical. I've had some recent experience with physical problems that leads me to believe that this boat will be the best boat for me now and in the forseeable future. It will be a test bed to try out many new ideas and I'll be able to sail it (almost) no matter what happens over the next few years. I have some interest here from a couple of other sailors that want to try the thing when I get it done. I will use this thread to keep track of progress starting now- at the very begining. I've gone from discussing and thinking about an idea to this boat as a final version. When the lines are completed I'll post some views of the boat. This won't go as fast as some other projects have on this board but
I'll give it all the time I can.
This is a 14.75' version of the boats discussed in the previous thread with some important differences. First, it does not have a planing hull-rather it will have a low wetted surface hull with a maximum beam at the waterline of 20"
for a beam to length ratio of 8.8/1 on a double-ended hull.It will use a 12' Trapwing that sweeps a little aft when viewed from above so that the 110 pounds(variable-easily adjustable) in the wing will move aft a bit as it moves out; both the wing and skipper will be able to slide aft. It is designed to use lifting foils
OFF THE WIND primarily- though since the keel cants 20° and the boat is designed to sail upwind at a 15° maximum angle of heel the mainfoil will be "shiftable" to allow it to help generate lateral resistance upwind. As I said, this is my personal boat and with my weight in it and the ballasted daggerboard in place upwind foiling is not possible. However, the boat can easily be reconfigured in a year or two with a more powerful Trapwing/ Rig setup so that may be possible.Offwind foiling is defintely possible and what this thing is designed to do in fairly light air. Upwind foiling will be theoretically possible with the boat as it's first built with a 160 pound skipper. My personal preference is to not make the boat too much "on edge" to begin with to give me time to learn to use the Trapwing and to get comfortable with the new way of sailing that this represents.
If you've got any constructive comments or suggestions I'd love to hear 'em...
---Max wl beam- 20"
---SA: upwind 135 sq.ft. downwind 255
Displacement,all up: 545 with 75 lb. ballasted daggerboard ; 488 w/o ballast but with small amount of weight added to Trapwing to keep RM the same. Note that figures here represent sailing with a 230lb. skipper; the boat could easily be sailed by anybody from about 120lb's on up with a corresponding performance increase.
---D/L ratio: 75 with ballast in board; 67.8 w/o.
--SA/D: upwind-32.4 with ballast in board ; 34.97 w/o ; downwind-w/daggerboard ballast-61.29 w/o-66 ..With a 160 pounder on board this can go up to 73 offwind. Note that with 120sq.ft.spinnaker up this boat has a better power to weight ratio than the International Moth even with the ballast in the daggerboard...
---SCP/Total Weight: .27 with ballast in board ; .3 w/o
---The boat will be built very lightly with help from a composites company near here.
The trapwing is back!!
Hi Doug, I will reserve my main criticisms of the new boat until we see some drawings at least. Are you going to post these soon?
As discussed in the previous thread a couple of months ago, foiling at high speed when the skipper sits inside the hull seems to be fairly unlikely in most conditions, even with the unballasted centreboard.
The main problem I see is the moment by moment trim of the trapwing when using the unballasted version. Can you see this huge thing hitting the water on a regular basis and causing the whole boat to come to a sickening stop.
Are you intending to use lateral buoyancy pods to prevent regular capsizes? I look forward to the next step of your project.
aeroSKIFF 16 donated
As I stated in the first post I'm using all the hardware, mast and hydrofoils off the aeroSKIFF 16 prototype for the new Trapwing 14. So I've donated the hull as you see it here:
to the junior sailing program at Calema Windsurfing/Sailing School in Merritt Island , Fl.
The boat will sport a "normal" (Dotan) kickup rudder and a daggerboard with a modified
windsurfing rig initialy and will no longer be capable of foiling(at least for now). It's about 150 lb.'s in that configuration and I imagine that the kids will have a blast with it.
And I wind up with most of everything I need to fit out the 14-which is much more suitable for me at this time.One more small step forward....
Trapwing 14(16.75)/ CHANGE # 1
I'm answering this portion of Mr. Hough's post in ths thread since it is more appropriate than the Moth thread:
Posted by RHOUGH under "Moth on Foils.." 7/8/06
" I'll bet that you can build a fun to sail "sit in" boat. Why it has to be a single track foiler is beyond me.
Why not start with a trimaran platform to eliminate the gadgets needed to balance the thing and optimize the design for low speed take-off rather than top speed. You have already done most of the homework on what it takes for early lift off and you have a working prototype. I would think that the chances of success would be greater starting from what works now, rather than from a clean sheet of paper."
In essence I am starting with what I know works: the hydrofoils from the aeroSKIFF are being used initially in the new boat as is the mast. If the sails can be cost effectively cut down I'll use them to start with as well.
And I've built numerous RC models utilizing movable ballast systems that gives me a real appreciation for the SDB(Sliding Deck Ballast)
mechanics and what it takes to make them work.
This boat may be described as a "trimaran" by some because of the buoyancy pods at each end of the wing but the main purpose is to explore the concept of a self-rightng foiling keelboat. I believe totaly in the concept because if it works it will open up high performance sailing to many more people than is possible now-older,smaller, larger fatter,disabled-whatever the reason for the infirmity this boat will let you sail like a bat out of hell.No RM from the crew means virtually anyone up to the max crew weight can sail the thing.
I've had some trouble recently that gave me a taste of what it's like to not be able to sail in a physically demanding boat and it has made me determined to try to develop this system. Maybe it won't work-so what! I may inspire somebody else to make it work.And if it does what I think it can -wow-will it be a blast! And this is important: I'll make what I learn available to anyone interested.
CHANGE # 1---I'm still working on the design and because of many factors I've decided to increase LOA to 16.75'. The increase won't appreciably affect cost since the wl and deck beam will stay the same-everything stays the same except D/L ratio which goes down and beam to length ratio which goes up . This will give me more latitude in experimenting with wing weight and powering up down the line after I master the first, relatively low powered, version of the boat.
I will post (or have a friend post) some sketches before too long.
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