Hi D L hi Steve and all

REALLY a good definitive post on the 18 SQ .thanks DL saving that one.
Would reiterate contacting John L ON THE HULL DESIGN and const. techniques and numerous aspects of any 18 sq project any sailor wanted to build or undertake.
With 194 sq ft on taller mast section and the carrying power and resulting forces of added beam it takes more hull volume forward to counteract the greater sail forces produced . An A Class type hull would generally become overpowered in the upper wind range and tend to drive its bow down and into waves.
John's LDC design and the Coyote 18 sqs had very flat full hull sections and plenty of volume forward for good reason .
One problem they had with 10 or 11 ft beam was the boats tacked so fast they could never get across quickly enough.
Followed John's development over a few years of building them , He tried a taller mast and sail in earlier years before winning the 18 sq Nationals finally . The taller mast he found was not ideal in gusting conditions were others with closer to 30 ft masts excellerated through gusts while he was up and down too often , beam was increased in earlier years also ,but found the boat designs that flew a hull earlier with less beam were faster , It was really a trial and error process in finding the right combination of beam mast sail componants to work together for average targeted wind speeds.
John said that the biggest change since he was active in the A Class and 18sq is not hull building technique ,but all the great lightweight hardware and rigging componants that are available now. The CF masts and sail materials have improved as well .
John developed a combination alum and top portion C F mast , a great innovation back then for the class.

Steve -recall your a larger sailor 220 plus ,like me ,so an A Class cat is not ideal ,-Interestingly John and others started in A Class cats then moved to the 18 sqs , they liked the unlimited beam aspect and thought the 18 sq formula had a wider appeal to a variety of sailors light or heavy.
There are however very few 18 sq s being actively raced ,though a great singlehanded class concept.

have fun .