Hi Bill

Great racing recently , running aground ,snapping a rudder, capsizing ,-righting and sailing well to win O A always makes the finish a little more rewarding.
race story -
http://www.catsailor.com/Stories_Temp/Stplchs03.htm

Agree --a general design discussion of hulls only of various sizes and different intended functions will not be benificial unless targeted to a specific type and with a broader understanding of design .

The knowledge and experience gained from designing and producing a series of successfull cat designs ranging from 15 to 30 ft --SC 15 --17 19-- 20 --Arc 21 22 RC 25 -27 and a 30 --and I,m sure a wide range of experimental type craft in between , now allows the ready applicable calc. or formula for a particular cat. size and desired function within a targeted design criteria. From going through this catamaran design exercize successfully numerous times you have the wonderfull ability to apply the correct series of engineering calc required , and can readily recall them having real models of each to relate to .
SC link http://www.aquarius-sail.com/

I like Gareth's idea , I,m here to learn more , think your correctly stating that if the design comparisons are to be benificial they should target a specific type ,but also that Naval architecture is complex and it will take some time to comprehend the intrical aspects .
--It would still be interesting to discuss design, several do have auto cad to help visualize it all .
There are numerous sites with basic lines and jpg pics for comparison also , this from the Aussie C cat challenge group .http://www.lacaustralia.com/design/challenge.htm

It may start with the A Class per example used per pic .
Some great video from the Worlds here
http://a-class.org.nz/photos_2004_worlds_video.htm
Defining all basic elements of catamaran design then applying them to targeted design criteria and type like A Class cats ,-then other design development class categories .

Like the A Class intnl reference to {big pond }
as opposed to a big fish in a small pond
http://www.users.bigpond.com/aiadca/index.html

a Class rules and basic boat specs are here -
http://www.usaca.info/

One interesting aspect of this class is many designers also race in it . So sailing techniques and practical insights instincts and intuition also come into play .
The downwind sailing technique of hull up with crew back may lead some larger crew to desire more volume towards the stern for example.
The A-s are highly refined and specialized type with matching mast flex and sail to crew weight as well.

It would be very interesting to run through variables of design in A-s - typical design --then add volume in the sterns and run through the numbers and a visual pic to relate it to ,--then canted hulls - etc .

It might be best if Rick set up a Design build specific category on Catsailor .

All the best Bill -& Gareth

Carl R