After reading some of the reactions to my thought, and after thinking about some of the concerns, including my own concern about glare on the eyes while sailing, I realized that this idea is indeed viable. (that is IF orange or red polypropelyne tramp fabric can be manufacuted)

I was concerned with glare to the sailors' eyes. Well then it dawned upon me that I used to sail a Hobie 18 with a very White trampoline and it never bothered me. In fact, the lighter the color, the cooler the fabric remains when it is exposed to the radiant heat effect of direct sunlight.

I am using a bright blue trampoline and while it is brilliant in reflective quality, pretty in appearance, cool to the touch, and resistant to solar deterioration, ... it happens to be the same color as the sky and water!

Painting the bottom of the tramp is not a great option because I was hoping to maintain upright visibility to helicoptors as well as being brightly visible from both sides of the tramp while capsized.

I do like the idea of coloring the keels, but how much weight would that add. How much expense?

The tramp is already there, no added weight, is one of the largest exposed surfaces on the boat, and can be spoted from a helicopter when the catamaran is in any likely posture that it might strike.

[color:"orange"]GARY[/color]