My Magic Marine Revolution (which I advice everybody who has backproblems) has the same safety knife described above.

But this spring, when I was trapped with my trapeze hook in my trampnet, it wasn't a big help. Somehow I couldn't reach for it.

With regard to the trapeze hook, I always wondered why the cat scene did not switch to triangle formed hooks like we did in the windsurf scene.
I can still remember me the day, about 30 years ago, that I was trapped with my single trapeze hook under my windsurfsail. I had imitated this hook on a piece of wood, looking at a obscure picture taken in Hawaii. Trapezes where just invented and not for sale in Holland. Until this triangle hooks came on the market, I always surfed with a knife attached to my suit.

This triangle principle by the way leads the trapeze rope always to the smaller end, so it can be freed easely when tangled around the hook. Nowadays the trapeze ropes are also changed by ropes with a rather stiff tube around, so they tangle less.

This summer I got trapped again under water with my windsurf trapeze when my sail washed over a fixed thight swimming line for the coast, while my board and me were washed underneath. Still it took me almost a minute to free myself, holding breath.

So hooks and lines never go well together and are always a potential danger.

With that in mind, I'm now trying to fabricate a keyhole system for my Revolution cat trapeze. Based on a flat plate.