Hetland
Contributor
Entirely out of idle curiousity: what'd he say? I guess for a shoulder/elbow-length one you'd have to visit your local SCA chapter's meet-up and talk to their armourers, but AFAIK they do all sorts of fun stuff: riveted Al, butted Ti, welded steel... Probably costly but compared to hospital bills, lost work, etc. (chopper gas bill?), I expect you could buy two, pay double, and still come out ahead.
The sharks they feed in the Caribbean are typically reef sharks. Their behavior is much different than what you see from a lemon shark, even tigers and hammerheads, which are the three sharks you're most likely to see in these Jupiter dives. Lemons care nothing about humans, you're something to steer around on their way to a fish. I had one sample a strobe once, and she didn't even put a scratch on the housing plastic. The tigers (in this context) are about the same, but they're more curious once they're relaxed, and they like to explore things, especially contrasting colors, and anything yellow (Randy warns you about this, and instructs you how to act if one gets too close for comfort). Greater Hammerheads also don't care about you unless you're a fish. They're very skittish, and they can literally sense you're excitement. You really have to relax yourself, and be completely calm for one to get close to you.
Chain mail would weigh Randy down, and he wouldn't be able to move as quickly as he needs to to keep all the sharks wrangled. The sharks watch each other, and quickly figure out what gets them a fish, and what gets them ignored.