mark,

This is what I found after some 60 seconds on the internet and thanks to a post by Same Evans.

http://www.sharkcatamaranclass.org./WHAT.HTML

Shark specs

Length 20 ft (= 6.10 mtr)
Width 10 ft ( = 3.05 mtr)
Weight 450 lbs (= 204 kg)
Mast Height 28.5'= 8.69 mtr => give mainsail luff estimate of 8.19 mtr.
Sailarea total 275 sq ft. = 25.6 sq. mtr. => lets divide that into 18.6 sq.mtr. main and 7 sq.mtr jib
Jib luff should be about 5 mtr with a mastlength and boat width like this.
daggerBoards
No spi

These estimates (and facts) give the shark a provisional rating (we had to guess at some specs) off

Light 99
Heavy 98


I ran the numbers on the Hobei 20 as well (the number that I know or estimate)

specs

Length waterline = 5.82 mtr.
width = 2.5 mtr (?)
weight = 201 kg
main = 17.97 sq. mtr. by 8.81 mtr luff
jib - 6.34 sq. mtr. by 5.74 mtr
Boards
No spi


NMBR ratings

light 100
heavy 102

Mark I send you an excelsheet so you can punch in the numbers of some other boats you need yourself

Wouter