From one package to another

[Willallison]

Got another one for you:
The clunky old (Borrowed!) version of Multisurf that I use won't calculate heeled stability. To try to overcome this, I exported the hull as IGES surfaces then inported it into a demo of prosurf. Most of the hydrostatics come out the same. But when I tried to do it with a catamaran, Prosurf gives me a displacement of almost double!:confused:
Any clues?

[Willallison]

hmmm... not takers huh?

Well to complicate matters further, I tried running the Hydros through Rhino / Phaser. Get a displacement of a little over half the correct figure.....:confused: :confused: :confused:

In the end, I did it the old fashioned way - a planimeter, 10 pages of calculations and a pencil - a lot of work, but at least I got the right answer (I hope...;) )