My favourite haunt is Thorness Bay on the Island (holiday hut on the cliff) where the reef goes out quite a long way into the bay. The one off Gurnard is well known about and boats seem to keep clear of that one.
I have seen two accidents in Thorness Bay. Both were ribs coming for a days water skiing. All seems perfect as the bay is quite sheltered and whilst the tide is up, no problem. One moment their bombing about towing skier thinking 'this is the reason we spend loads-a-money on ribs', the next run round, smack, the prop is smashed
Being single engined there was a lot of red faces.The tide does not have to have been going out for long and the reef is not exsposed. It's just very shallow on one side very quickly.
Although lobster pots are a complete menace (espcially the half submerged ones and at night) they do give you some idea of hidden problems, as the locals will put them around the ledges of the reef.
My heart goes out to the families of those involved, as I know I have done some stupid things when I'm afloat.