Allow me to play the devils advocate.
I did some spec checking and I compared some aspects of RG's proposal to the stated design goals.
RG wrote to me that he used a copy of the Moth rig in his drawings. The Moth rig is not an unstayed rig and it is highly unlikely that an unstayed mast will remain as straight a given in the pictures when loaded up. The Moth rig is actually 8.00 sq. mtr on a 6.250 mtr mast. More specs of other boats can of course be found on :
http://www.xs4all.nl/~whijink/F12/RG's design looks very well and is very succesful in attracting the sailors to the F12 idea. That is a very important development. Without some good promo the F12 project will be struggling. I too appreciate that very much.
Still, I'm a little bit at a loss in how to incorporate this design in the larger F12 scheme. Afterall it is basically his LR2 A-cat design scaled down in size with a Moth rig on it. Neither of these components is particulary inexpensive or easy to (home)build. But homebuilding is indeed regarded as the way to kick-start the F12 class till a more professional builder can be convinced to invest in the project. Of course the chined hull construction, as also shown by RG himself, is alot more in line with these design goals. It may be wise to focus on that part of the design and forget about the fully rounded version as I fear it will really problematic to prototype and build the class on the fully rounded version. We shouldn't give people to wrong idea by showing that version around to much either, for I fear they will never "get" the fully rounded version.
At this instance we must also appreciate how problematic it can be when the class is started and grown initiallly on the chined hull version only to have a professional builder do the rounded hulls later. Will all the boats build in the initial stages by outdated by that, how will their owners react to that, will they even consider building the boats when they are aware that such a thing may happen later. Such considerations are simply skipped over now.
RG comments on how chined hulls are draggy, or at least when compared to say his fully rounded hull. This may give further weight to the problems of transitioning from chined hulls to rounded hull later in the existance of the class. But I also believe it misses the F12 point somewhere. Indeed it stands to reason to expect the chined hull to be more draggy, but how important is this in the greater scheme. A Hobie 16 is seriously outdated in relation to say an F16 but the performance difference between them is only 15 %, most of it coming from the differences in the rig and overall weight. How much of that difference is the result of having inferiour hulls and lacking daggerboards ? Take a look at the Paper Tiger, a chined design that nobody regards as being slow.
This leads us to the following question, which is a very important one for the F12, how much additional cost and building effort is say 5% additional performance worth ?
It shall be obvious that I take a totally different take on things. I feel that it is far more valuable to have a very easily and inexpensively build F12 and work that quality into class growth. I don't believe that losing an X amount of performance (limited to 15% at max) is "worth it" if the class is strickt One-Design and will be beating a laser dinghy anyway.
At a certain point enough is enough and at that time there is more to be gained by optimizing the building time and costs. For a concept (sailing class) to be succesful, the whole picture must be right not just a few parts of it.
Welding ? Something I really tried to avoid in the F12 design. Homebuilders can not easily do it. It is also not needed. The same with bending the tubes.
Daggerboards have been covered already. Interesting to note is that assuming a chined hull is more draggy then it may well be more resistant to sideways slip ! I've sailed boardless cats for a long time and the pointing difference between say a nacra 5.7 and a nacra 5.8 wasn't very large at all. It is to us to decide whether the difference is large enough to decide to use daggerboards on the F12. In this balancing act we must not forget that daggerboards are a custom made item and do indeed add building costs and complexity to the design. They are also one more thing to get broken. To us the decision whether the advantages outweight the drawbacks.
Four of the more important design goals as stated explicetly last january were a F12 that could be build for 3000 Euro's or less by a relative homebuilder in 100 hours or less, fully rigged and derigged in max 5 minutes and fully assembled/disassembled in max 10 minutes. I still believe these to be critical for the succesful launch of the F12 class; otherwise I too would just have taken a CAD drawing of an F16 and scaled that down while replacing the 6 in the class logo by a 2.
Wouter
![[Linked Image]](http://www.catsailor.com/bb_files/123761-Moth_platform_01.jpg)
![[Linked Image]](http://www.catsailor.com/bb_files/123761-Moth_platform_02.jpg)
