Mark,

Your data is not correct.




An A-class cat is actually.

200 mm narrower
490 mm longer (and not 300 mm)
35 kg lighter (on average)
1.20 sq. mtr. smaller in its mainsail area (and not 2.25 sq. mtr.)
600 mm shorter in mast length AND 700 mm longer in mainsail luff length.





Now that is a very interesting question.

Personally I think we must recognize that the A-class rig and platform has been developped over a long time and it is developped to be a very good upwind performers The F16's haven't had nearly the same amount of development in their rigs yet. Also we are losing some upwind performance because of the spinnaker package and the spi halyard running up the mast. I saw a good trick on a singlehanded F16 recently. The owner had moved the spi halyard so that it run up along the forestay instead of along side the mast. This will most definately improve flow in that very important spot, the mast. In the latest club race we had he nailed us all upwind, working up between 2.5 and 6 minutes lead. He lost some on the downwind legs, but he is still new to spi sailing.

Additionally our F16 hulls are a (good) compromise between diverging requirements. Afterall the A-cat hulls are designed to carry ONLY a single skipper while our F16 hulls are also designed a crew of 150 kg well and be a forgiving hullshape when crashing through waves under a spinnaker. Additionally our hulls are made to handle being a platform that is short and wide instead of being long and narrow. The penalty is drag. From a performance perspective, probabbly the best singlehander setup is a 5.5 mtr long by 2.75 mtr wide platform (18 feet by 9 feet) that weights under 100 kg, carries a 15 sq. mtr. mainsail on a 9 mtr carbon mast and a F16 size spinnaker. But that was not something we could get going in a commercial viable way.

In the end of the day the whoel A-class concept is optimized for a single purpose while the F16's necessarily are a compromise between 1-up and 2-up sailing and all the little aspects in which we are suboptimal add up. Especially on upwind legs as here efficiency is so important in the way of pointing without losing speed.

But also we must never forget that weight is a large factor in performance. Afterall, each time you travel ahead by a boatlength you will have pushed the overall weight in water volume out of the way. The A-cats just push 150/180 = 83.3 % => 17 % less weight aside. The F16's have 1.09 % more sailarea and "83.3 % times 1.09 %" equals 90.5 % in favour for the A-cat. So here they have about 10 % advantage. Naturally this is a rather crude calculation but suprisingly enough it comes really close your on the water experience. Sometimes things are that simple.

If you as a human being had to dig a hole that is 10 % larger then that of your neighbour then chances are that you'll take 10 % longer to do so.

But of course you should win all that back, AND MORE, on the downwind leg after deploying your spinnaker !

That is unless the A-cat sailors insist on running triangular courses of very modest length with alot of laps and you cave into that ! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Wouter