Request a quick favor

I'd like to request a favor of someone with a decent hydrostatics module and x,y,z scaling related to
http://www.boatdesign.net/forums/showthread.php?threadid=327

Take any monohull boat. Note it's beam, its whetted surface, and its transverse moment of inertia - "I(t)". Now double it's size, then scale the beam until the ratio of "I(t)" to whetted surface is the same as for the smaller version. What is the original beam, and what is the new one?

Actually, it'd be nice to get this result for several different boats. This'll really help me out. Thanks!

 

A correction

Oops, one modification. What I want is the beam at which I/ws is twice what it was on the same boat at half the size.
If I(t)/whetted surface was 10 on the original boat,
I'd like to know at what beam I(t)/whetted surface = 20 after the boat has been doubled in size.