http://www.boatdesign.net/forums/multihulls/load-paths-catamaran-26229-2.html

In this example thread, the discussion deals with the different component forces imposed and stresses created as it relates to the bridge between the hulls. The forces externally imposed on hulls in this case are being discussed. The very different loads and reaction to those loadings produces variable torsion on the structure which must be resisted. (If it were symmetrical, it would just be bending). As one hull engages the seaway on the starboard hull's bow, the port hull's is being tipped down. The the effect is "catty" cornered, if you like.

Below is a link to a diagram which appears down in the thread.
http://www.boatdesign.net/forums/multihulls/load-paths-catamaran-26229-2.html

You may find the discussion, and others on that site informative.

Loads imposed and the reactions on the your hulls, the structure of the boat, the rigging, etc are not symmetric as you sail in the real world. As the seaway changes and the velocity on the wind fluctuates, the hulls are seeing much different conditions. And the rudders' loads are different too.

The differential effects on the hulls may be more dramatic than you intuitive would have thought.

Anyway this post is from a (non-Polish) ski free zone. ;^))). Keep you bows (tips) up ...

PS - your Manta's distance between your sail props looks a lot better than the powerboat like Alpha's. This whole thread has led me to look at cats under bodies.