when i built my s&g guilemot i read the building logs that both Nick and George Mcquade wrote. they were very helpful.
this might help.....
lets use 'position 20' as an example.
width 0 is the verticle center line. the very top point of the deck at that point is 6.55. this is the height above the design waterline. hieght at 0 on the keel is a negative number because it is below the design waterline.
the sheer measurement is 5.4 inches out horizontaly from the vertical c/l and 2.23 inches above the waterline.
hope that helps;
daren.....