I spent ages looking at swim platforms, boarding ladders (still to sort a decent one out) and all kinds of other stuff for our wakeboarding/ringo outings. The best solution I found, and the most flexible, was to go for the Aquaglide Airport towable platform. We blow it up, tow it out, anchor it, dump kit and various bodies on it and then use it as a fixed platform for swimming, diving, picnic etc. It has been fantastic, it also has lots of mooring eyes for hooking the boat up to therefore avoiding throwing more anchors out. It also avoids the whole bumping into and out of the beach fiasco if you have lots of different people wanting to play.