For a description on some shark incidents in South Africa, see:
www.surfski.info/content/view/368/147/
In the "related links" box on the right of the page, there are some other stories too.
In the course of researching some of the stories, I spoke to some experts on Great White sharks and they said, basically:
- Sharks are inquisitive, and most "incidents" can be attributed to the sharks simply "investigating".
- Sharks are like any other predator and react (like cats for example) to signs of panic. If you're in the water with a shark, it's better to swim towards it rather than away from it.
- Sharks are individuals. 99.9% will come look at a ski, realise that it's not a prey object and will move on. But there are individuals who'll want to mouth the ski to see what it is.
One of the researchers, Alison Kock, who has been working with GW sharks here in False Bay for years, has been experimenting with "critter cams" which attach to the sharks dorsal fin. After a couple of hours the camera releases itself, you pick it up and you can see what the shark was up to. She said it was fascinating to see just how inquisitive the animals are - the camera shows them checking out all kinds of things from kelp to plastic bags.
I have seen precisely one shark in 8 years (shat myself at the time but be that as it may) and had one come and look at me (spotted by a buddy who said the fin came within 3m of the back of the ski). But I am certain that they come and check us out all the time.
What to do when a shark comes up? Don't act like frightened prey! Either stop paddling and raft together, or continue gently - but don't panic and start thrashing the water. If you're in the water, stay close to the ski, draw your legs up so they're not hanging down. Get out of the water!
And, as one of the researchers said, if you see a shark, "enjoy the moment!" It's rare enough to see them, might as well appreciate it! They are magnificent (if scary) animals!