Efficiency: Submerged transoms

Again you might get some data by using prelimina.com. From what little I understand Prof. Basic implemented a prediction for how an immersed transom. How accurate I can't judge:

Trim & sinkage solver – Prelimina https://prelimina.com/2019/10/trim-sinkage-solver/

If you do use it please post the results. I'd be curious about the results and how accurate others would judge those results.

I'd be curious about the pitching too but I think you need to look at that like a complex spring system with excitation through buoyancy, dampening through asymmetry or foils and oscillation through rotational inertia from how the weight is distributed. And resonance from hitting certain wave lengths.

 

A former member (may still be member, don't see him post) "Groper" designed and built a fast displacement cat around 11 meters with rounded hulls and a submerged transom stern, might be some clues in that build thread. I recall he wasn't 100% happy with the ride, with some slamming on the flat section of the hulls forward