Sea water (salt water) conducts electricity very well.
Fresh water does not. Hence, being on a cat in rain, not touching metal, you can stay not grounded to the sea.

However, if your trampoline is sprayed by sea water from wave wash, you are probably very unsafe.

A drysuit may help a lot.
The wet surface may act as a Faraday cage, maybe?

A friend of mine wearing a drysuit was struck by a lightning on the beach. He told me that he observed the flash travelling on the surface of the suit and felt the pressure, but was not injured. At least he claims he was not injured.

Would be nice if someone got the physicists who really know about lightning to come up with consensus recommendations for (dinghy) sailors.

Stein