I was going to make the same suggestion as esshup, but hadn't done it myself, so I didn't write it up.
If you like his suggestion, then you might try to make a "dual purpose" platform. A floating dock has been a big hit in every swimming pond that I have been invited to use. Sometimes the teenagers escape from the little kids during family visits. It can be a goal for new swimmers to work on their stroke and endurance to achieve, etc.
If you can also use the floating dock as your work barge, then that would be gravy! I would make it so I could unhook the anchor cables and hook them onto a float until I returned the barge back to its "normal" position.
