I had served as crew in small yachts in & out of Sharpness, but in 1994 I was skipper/owner for the first time of my own boat. I'd approached Sharpness a little early - mistake born of excess caution. There are what's called 'leading marks' - points which you must keep 'in transit - lined up' to stay in the deep water - all the way from the first bridge to Sharpness. The last such leading marks would lead me to the outer lock at Sharpness. Problem. According to my - new - chart, to follow those marks would lead me straight over what was marked as 'Bull Rock'. Being allergic to anything called 'rock', I allowed my course to deviate to the west, Welsh bank/ Wrong! Bang! We were over on our elbow, mud coming up the plug hole in the galley sink! Assuming this was Bull Rock, as we floated, I moved further west (in military parlance it's call 'reinforcing failure'. Bang! Over we went again. I may not be the sharpest knife in the box, but I can learn when panicked - next time we floated, I moved east into deeper water. We secured to the east harbour wall, breathed out for the first time in a while, & waited for the lock to open & allow us in. The SARA rescue launch came roaring up, having been alerted to our 'difficulty'. I explained why I'd strayed from the leading marks, to avoid Bull Rock. They laughed. 'She was dynamited back in the 1930's!' Put not your trust in princes or, it seems, charts! p.s. I did it many times after that, & survived!