.. I think I can see what you are trying to achieve with the concave stern underside and the 'sprayrail'. I think it's fascinating to see peeople trying different ideas on these boats and only head-to-head testing will show us what works and what possibly doesn't.
What I tried to achieve is more 'track' and a better flow to maximize the lower performance of daggerless hull.
Exactly, only head to head testing will tell us how good this extreme shape is doing.
As for now, the boat is really palanning in high winds and drag is being greatly reduced in lower ones, just look at the picture took from backwards.
You say the all up weight of the RC16 is 140Kg? ... Are there any opportunities for weight saving in the platform?
I'm just thinking that with the external stiffening offered by the spray rail there may be the chance to reduce the hull layup further? It would be really cool to get a boardless F16 that is under say 120Kg or even closer to the minimum of 107Kg for a sloop F16.... <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />
I'm calculating over, but remember that we are using coremat to reduce costs.
You´re right again, all the way sprayrails, gives a 'T' shape to hull sidewards, making it a lot more stronger, add that we've have a 'curved' deck and you´re talking about one of the better structural shapes possible for a cat.
The boat is not heavy at all indeed, and I´ve wrote before, we are using heavy profiles for masts and beams.
Regarding design:
Lead by Sebastien Magnen comments on a better structural curved bow design (he owns a Dart Hawk back in France) I've studied the Hawk , the Spitfire and its predecessor the Dart 16 itself, but the lines are 100% original as the prototype and current production hull (no nodification at all till now) was issued from our F18 orignal hull mold(Designed from scratch with Tornado, Bulogne's Cirrus, and J Valer Tiger as models)
I also noted the use of Srayrails in several new cat designs, as the Alinghi for ie. Some research and pictures proved me that they were really functional, more here with our short breaking waves.
In fact I almost applied the channels and concaves to the F18 desing in July 2005 but it was too much for a 1st boat.
This past winter due to demand for a recreational and more afforadable boat I spent some months cad designing and shaping myself the 16 prototype.
As here we have muddy waters and short breaking waves conditions I´ve never thought of and inverted bow design. Also our most distinctive feature is great volume, we have almost 70cm freeboard for the F18 and 62cm aprox for the 16. We need high beams and extra flotation here.
Till now we proved right with these extra volumes as we are having huge margin to 'attack' in a reach or with Spi, or getting out of incredible pitch pole situations, just take a look to this spi F18 video at after the flag footage, any other cat would have go down. I was getting better with Spi at that time, in fact was my 1st time with 20knots winds, so is full credit to the hulls that we've didn´t pitch pole hard.
http://www.youtube.com/watch?v=2K3bSBHO0Kc rarely offshore winds and persistent non breaking waves that day.
So that´s the story behind our designs, 'torpedo tube' included, but hey, always some crazy guys are innovating, let see how far channels and concaves get in cat designs.