Trimaran Resistance and Powering with Hullspeed/Navcad

[Navall]

Hi all!

I am designing a trimaran at the moment and i came to the point of resistance prediction.

The hull model is done in rhino/orca.

My question is how can I calculate the resistance/powering? Maxsurf's hullspeed offers the slende body method which they claim that is appropriate for multihulls. However, hullspeed does offer nothing more for powering.

Navcad on the otherside, is really good for powering but does not seem to have a method (like slender body) for trimarans. Only for catamarans.

The final questions?
Is possible to calculate the resistance of a trimaran in Navcad?
Is possible to manually input resistance curves in navcad from e.g. hullspeed?

Thanx !