It may indeed happen a lot. I recall reading someplace that you are more likely to have someone stop and help you (say your car is broken down) on a lonely country road, then you are if you are on a highway with dozens of cars passing you every moment.

Apparently, it the presence of lots of other cars (boats?) in the area makes people think that there really can't be a problem or someone else would have stopped to help already, so they don't stop. On the country road, they can see they are the only one who can help, and are more likely to stop and help.

It sounds like there were other boaters in the area; perhaps the area is well traveled. So they thought if there was trouble, someone would have helped already. . .