[jjcm]

One fun thing you get to do in long distance outrigger canoe races in hawaii is crew changes.

Generally, outrigger races have 6 people in the boat and a 9 person team. An escort boat will hold your reserve people, and then drop them in front of the canoe when you need to swap people out.

The problem is that you need to drop people around 200m in front of the canoe so the canoe can have enough time to prep for the crew change, but with that distance, the wave height can obscure the crew from the person steering.

The solution? If you're the one being dropped, you're expected to splash violently. Create as much splash as possible so the canoe can see you, even behind a wave.

The fun part is what gives signal to the canoe is the same thing that gives signal to sharks. Our coach used to say the adrenaline helps us in the race.

[anamax]

I wonder why a balloon or an extra-long safety sausage wouldn't work.

[jjcm]

The last thing you'd want is a balloon or an inflatable hampering your movements. Getting into the canoe as it's moving is a tricky, practiced and precise motion.

A hyperbolic example would be imagine a pole vaulter with a safety sausage attached to them.