Bearing in mind that the pivot bolt for teh centreboard is below the waterline, I am not too sure that taking it out afloat is all that great an idea. If I ever have to do it (shudder) I think I will get my marina to lift me out and pop me, (or her rather) on a cradle, as they did last year, when I was towing her down to Mylor, as shown below. But they don't do it for free...
Peter, do you have a lines drawing for the BC20? I would love a copy if you do.