Rolf, you are quite right about working out my shoulders. Actually it is nice to meet someone who knows what shoulder labrums (or is it labra) are. It toke me fifteen years of shopping around fysicians before the right diagnosis was done. And that only after the time that MRI was available for non-cancer patients.
The problem with strengthening the rotatorcuff muscles is the disloading of the labrum itself. Strong painkillers (NSAID's) after effort helps me. I keep trying because I'm still a sea junkie!

Yes I know the beams seems a bit heavy and yes I know it seems guesswork. In fact it was that partly. I wanted to start with a solid wooden core, because of the natural resisting force of wood against bending and its own stiffness.
Standing on it in the middle in my living room, I could easily test this and add the necessary layers of fiber-epoxy composite.

Ofcourse I ended up with a construction with a lot of "spare". But that's okay, the stress loads at sea are dynamical so you have to multiply your calculations anyway.
To vary the dimensional section in the length is ofcourse a sensitive option; a bridge is the strongest in the middle.
Frankly, I forgot it and didn't consider it.

The trampoline is not a mesh, but an open net construction with very large mazes.I'm always at the trapeze and only have to pass during gibing. I never go through the wind the normal way.
This polyester net I have ordered in the States and it was worked off with rope-sides. The hulls were prepared for this with the standard Prindle holes in the sides for a thin lacing-cord which connects the net and the hull every 10 cm.
In fact I glued a polyester staff on the side , covered it with some layers fiber and drilled small holes every 10 cm. right through the staff.
I did the same on the aft beam and the front beam was laced around as you can see on the picture.

There are ofcourse no daggerboards, the hulls are assymetric. Round on the inside and flat on the outside. And the hulls are quite outbend to the outside in the lenghth direction.
Rudders and even the castings itself are also home-made from, you guessed it already, wood and epoxy composite layup. The main reason for adopting the oldfashioned Prindle ruddersystem as design, was the fact that I sail always single-handed.
At the beach I always have to start with my rudders high because of the undepth. So jib on, mainsail open, fighting against weather on the steeringtube. In the break or just after I have to click the rudders down and no way I come near the leeward side of the cat (it would capsize). So I have this rope system with which I can pull actually the rudders down.