Watch me get flamed here... Big Bags? Beach Towels? That is what comes on and off cruise ships...
My point less is more, secure footwear is valuable, most of us could circle a bunch of stuff you do not need on a sailing trip and will only be a burden to tot, try to keep dry, and clean up after. Who will be the maid on her hands and needs on your boat?
If it looks like it can hold sand or cannot be washed off easily in the salt water off the back of the boat consider leaving it at home... bring a little more easy to carry cash in its place.