when i was in South Africa the begginning of last year, one lad that does a lot of kayak fishing, said it wasn't uncommon for great whites to come up right beside your yak. As they do with any other boat. And as Davy has already siad you are entering their environment, and if you get bitten they are just tasting you to see what you are, like dogs and babbies do, everything in the mouth. Only thing is a sharks tasting can have some pretty serious consequences.