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

------------------------------
This jib pivot slide system was tested on a 26' racing boat for several years. I met the guy that did it online when he saw my original posts on this idea for rc boats. In addition, I tested models using it for three-four years. The high aspect masthead square top jib was tested on models and on my 16 footer. Seems like it will be very effective based on that testing.

 

Doug Why is it better to have the jib luff to leeward? I always thought that It was better to have the tack to windward, I suppose mainly to reduce sheet loads (Lugs, lateen,swing rigs, junks ,wings). I guess because your jib arrangement is balanced anyway,you feel that a leeward luff allows the jib to be sheeted in more without back winding the main ,or is it that the such a high aspect jibs main function is to keep the laminar flow attached to the critical leading edge of the main and you feel that this is done more effectively with the luff to leeward?

 

============
Timothy, the jib luff is right on the centerline like any other jib. Look at the pictures above including the model. Here is another picture of the 16 using the same type of jib w/o the sliding pivot:

 

Trapwing 15-planing versions

This post and its associated sketches pretty well define the planing hull version of the Trapwing concept. It is designed to be able to be configured in both a high power Turbo version, with numbers reflective of very powerfull skiffs, and in a less powerfull, less demanding version that will still be able to plane upwind with crew weights from 120 to 180 with maximum crew weight up to 220. The sailing configuration is also changeable from a "sit-in" arrangement for a single crew sitting in the center to sitting on the rail in special carbon seats(with backs and cushions) that simply plug in and are easily removable.
The 15 is the result of lots of experimenting and research into moderate and high performance planing versions of this concept-a concept that allows less athletic people to use on-deck movable ballast to experience the thrill of sailing a planing hull boat. Comments and suggestions welcome....

================
Click on images:

 

Somehow I doubt you really want to solicit feedback, perhaps it would be simpler to ask for unthinking support and validation. Twenty seven out of thirty five posts in this thread are your own.

Doug, this concept depends exclusively on a complex mechanical gizmo for it basic safety. If the trapwing fails, there is no way this boat will remain upright, given the potentially very powerful rig. To meet mathematical ratios necessary for upwind planing, the rig power is way out of proportion for operating with a trapwing failure. Given there is no option for hiking, this means a trapwing failure means capsize without recovery.

I've seen International Canoes with broken sliding seats, and they are not sailable or paddle-able. And on an IC, were talking about a highly mobile crew at a very high skill level.

Although the trapwing concept does provide a potentially valid answer to adding righting moment for mobility challenged (or plain lazy) crew, the lack of safety margin renders it unacceptable to me, and I'd hazard a guess it would be unacceptable to insurance carriers.

The biggest problem I see is that you are making the trapwing concept the PRIMARY and only righting moment contributor. The concept makes a lot more sense as a secondary aid. Putting buoyancy at the ends of the trapwing is only a failure mode asset if it is fixed in position, like a trimaran's amas. The complexity of the trapwing, the fact it is intended to move side to side, and the lack of margin for error is why I think the concept is unacceptable.

I know you don't agree with anyone who doesn't agree with you, and I really don't want to hear you "refute" these points with the same nonsense you've repeated over the years. The only acceptable argument you can post is pictures of the thing actually working, and a statement from an insurance company that they would underwrite a policy on the boat for use by the intended audience. Deeds, not words.

--
Bill

 

Trapwing 15

I welcome constructive criticism, suggestions or ideas. Some posts are presented with a "tone" that I may find objectionable coming ,as they many times do, with no technical grounds or references and coupled with a great deal of presumption. I appreciate them all, however, especially critical posts similar to those I quoted from Steve Clark. All of them help to think this out to one degree or another. I will answer all of them to the best of my ability.

From posts 20 & 34:
--The cockpit is self-bailing and the boat will be self-righting though a turbo version w/o the keel will be
experimented with.
-- The boat allows "sit-inside" control(as well as a fixed side to side removable rail seat with seat back and different rigs).

===============
-- The trapwing concept has been experimented with in model testing for over 10 years-there has never been a failure. As with any other boat, if this boat was to be introduced into production the full size version would undergo exhaustive testing of systems overseen by a marine engineer and naval architect. At present the plan is to build the 15 for my own personal use and testing.
-- The safety margin is designed in and is greater than that found on a keelboat(the keel might break or fall off) and is greater than that found on any multihull or performance dinghy of normal design. Again, this would be backed up by rigorous testing before a production version was introduced.
-- the part that I agree with from post 35: "..the trapwing concept does provide a potentially valid answer to adding righting moment for mobility challenged (or plain lazy) crew...."

 

Disagreeing can certainly be constructive, especially if it may prevent someone from being hurt.

I did point out that the trapwing concept may be a better idea as a SECONDARY aid to righting moment. Perhaps you have not considered that fixed buoyancy pods (amas actually) combined with your trapwing idea would be safer, have greater failure recovery and may still meet your performance goals. This would also reduce complexity dramatically and make things a lot more reliable.

I'm not against the idea of the trapwing, I'm against the idea of the trapwing as primary righting moment provider and as only active failure recovery method. Complexity is the enemy of reliability.

Rather than consider only the radical PRIMARY path forward, why not consider the incremental path forward where you cover your bets a little more carefully?

--
Bill

 

=================
Sounds like a tri to me and was considered early on. However, the system that will be used has been tested in models for a long time, as I mentioned above. And all that testing and experimenting led to the conclusion that the sliding wing with buoyancy pods at the ends represents the way to proceed with full scale testing-with significant advantages over a tri with fixed amas and movable ballast. Much was learned including the use of the combination of fixed keel and sliding on-deck ballast(trapwing) supported by trapeze wires, athwartship pivoting and its relationship to keeping the lee side of the wing clear of the water and the importance of F&A movement of the wing. The design elements that permit the simple trailering of the system, and the major elements of the structural design were tested in the models for functionality and improved over the years. It's time for full size testing in a boat that will serve as a pre-production prototype. I had initially wanted to carry this testing out on a 21' platform that will serve other experimental purposes as well. I have been persuaded that this concept should be evaluated with a design specifically developed for the Trapwing-hence the 15-and a possible 10' version. Full size testing is bound to refine the design even more and help to make it a simple ,exciting boat to sail without the requirement of athletic prowess. Ease of sailing and high performance are the essence of the concept but there are numerous levels of performance to be explored during testing. The Trapwing should be a lot of fun to sail with the crew having RM at their fingertips-it surely was a blast in model testing.
The performance advantages of the concept for a singlehanded sailor are potentially very exciting in all conditions. One of the most important characteristics of this concept is that the crew weight range is extremely wide since the crew adds nothing to RM-something like 120lb to 220 lb.

 

Trapwing 15

This was posted earlier in this thread but it sums up the advantages of a planing version of the Trapwing concept so well that I thought it was appropo to quote it here since it was done before I had finalized a planing design-the 15:


"One of the main themes of this design concept is that the resulting boat can be a self-righting keelboat. I was intrigued by the K1 concept( http://www.boatdesign.net/forums/sailboats/neat-singlehanded-keelboat-uk-30059.html ) where the designer chose a narrow waterline semi-circular section hull that was designed to be sailed heeled instead of flat like most planing hull dinghies. The Bongo is an example of a small keelboat with a planing hull. I've never really thought that was a good way to go because in order to plane the Bongo must be sailed flat which means that the keel bulb is not developing any RM. And while I like the K1 and the designers thinking I don't think it comes close to an easy to sail keelboat along the lines of a 2.4 meter. And no way are either the Bongo or the K1 "high performance".
--
The beauty of the Trapwing system seems to me to be that on a boat with a planing hull that has the power to plane in 10k or under it can be sailed flat upwind and downwind and can be designed to plane upwind and downwind.

And high performance with a self-righting capability thanks to the design of the movable ballast wing and a bulb keel. Also, since the weight in/on the wing and the wing itself is moving to develop righting moment the crew is not taxed physically and can sail the boat with the ease of a 2.4 meter but with much more performance. I don't think there is a small keelboat anywhere that offers all this and that makes it extremely attractive to me.

The advantages as I see them:
1) easy to sail by almost any weight sailor.
2) self-righting
3) high performance-planing upwind and downwind
4) variable wing ballast-moved manually or electrically
5) two seating options-a.sit in and, b. side to side
6) reefable rig

 

---------------------------------
Of course, I'm sure you read that the boat (non-turbo version) includes a fixed keel as back up and to right the boat from a pitchpole should that ever occur.
From the research I've done the trapwing system on a dinghy is far less complex than a canting keel(that has no backup)-and "safer" than any 'keel-only' boat for that matter. And again, the safety margin is designed in and would be backed up by thorough testing giving 100% confidence in the system.
Interestingly, Dave Trude( 2.4 meter sailor and webmaster at SA) has said he would sail the boat. He'd said that a couple of years ago and repeated it the other day. He also recommended another guy he thought might be interested and who lives in Florida. So there is interest and a lot of help available when it comes time to evaluate the concept from both the ablebodied and disabled perspectives.
This thing offers tremendous potential for high performance sailing without the athleticism normally associated with that kind of sailing-and is bound to create a great deal of excitement as people begin to experience it first hand.

 

With no hostility attached here, Doug... Just which of the many boats you have going, as "in development" projects, are you actually working on at the moment?

I'm seeing you go back and forth from 60 foot Moth, to C-Class Hydrop style foiler, to Trapwing I and II, to DSS this and People's Foiler That, to test bed 21 foot foiler-trapper-ballasted-winged-Dr. Sam exercise to.... the next cool concept from your imagination. ;-)

Truthfully, I'm just a bit more than confused about all this. Personally, I have four different design projects going on myself right now, though they are each much less complex than the above mentioned craft and they are, best of all, projects that have been requested by paying customers. Still, each time I sit down to the computer and sketch pad, I have to reacquaint myself with the details of each project, or I tend to crash around a bit before returning to smooth efficiency of purpose.

Which one of these boats of yours is actually going forward with a build by you, or anybody else? Do you have a priority involved here, or is it all just sort of blobbing along as one big amalgam. Are there any photos you can share with all of us that show the boat being built and best of all... do you have a launch date that we can look forward to with anticipation?

Call me confused, but all this seems to be just a bit tangled for my typically messy organization abilities and I'd like to bring it into focus a bit better.

 

========================
To the extent they can be(will be) those questions have already been answered in this thread and other threads.

 

Major Breakthru!!! Trapwing Proto

Thanks to Dave Trude ,I have made the acquaintance of one of the most respected coaches and boat builders involved with disabled sailing in the USA.
He is a well known championship sailor in many classes including the Lightning and several others.
Part of the good news is that he thinks the Trapwing concept has great potential-he loves the concept. The other part is that he will help to develop the boat.
With this encouragement I have decided to drop everything and concentrate 100% on the Trapwing prototype which will be based on an already existing hull and will resemble the 15 but be a couple of feet longer. I will devote myself to making this concept a reality and with help from Mark and Dave make it suitable for disabled sailing. All of us think it can be done and, if we do it, result in a remarkable new way to sail for ablebodied and disabled sailors. For a lot of reasons this has become the most important development project I have ever worked on with its potential to help thousands of sailors enjoy a new kind of sailing not yet seen on this planet. Thanks, guys!
Pictures of a model of the new prototype will ,hopefully, be up in a week or less.

 

Why are you wasting time building a model? Why not just build the boat?

 

=========================
A model is a long way from "wasting time"! A model helps to identify problems ahead of time and helps to visualize the way things work. I've built a model for almost every boat I've designed and built-it's a very usefull excercise.
The prototype is being built on an existing hull of a design of mine for which the original model exists. The "new" model will result from modifications made to the old model in about the same way it will be done full size and that will be a big help.