Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE
It's not a function of size, just look at some of the condomarans with 40' loa and 10 inches of clearance.
I seem to recall reading somewhere that the absolute minimum bridgedeck clearance you want is 19", from the lowest point of the bridgedeck to the water. This includes any Nacelle (spelling?) hanging down from the bridgedeck.
If you really want to understand this issue go to boatdesign.net and do a forum search, there is lots and lots of data, much of it from NA's and designers (richard woods posts there frequently) and you will get a fuller understanding of the issue.