This is a Cherub dinghy, being rigged for a Championship race on its side, as is the habit in that slightly unconventional class. This is handy for taking a look at the interior. The blue sail loosely draped over the mast is the spinnaker.
All this ends up in quite an assemblage of string, which can get quite confusing until you are used to it. Keeping the lines tidy is a useful discipline while sailing the boat, as tripping over ropes and falling overboard is pretty much a guaranteed race losing manouver. This especially applies to the halyards and painter which you won't actually use until you come to the shore again. This should be stowed neatly in a manner that will not come undone if you capsize, but can be got to easily if necessary.