Portishead Cruising Club races around it at high water several times each year. Even around high water the tide runs quite quickly. The island is used as a roost for many fist eating seabirds, and has its own aroma. I've considered going ashore, and if I did I would get someone to take me over there and anchor the dinghy in the tidal lee of the island and wait until the tide went out. Be wary that the sand becomes 'quick' on the rising tide.