Just an idea and maybe a weird one but I always thought if I had to leave my boat in a public area for an extended period I would cut some pieces of- don't laugh- chicken wire, or other probably nicer light, maybe welded, fence wire into sizes to fit across the tramp area (where are most valuable items) and then cable or chain it locked under the tramp. The mesh would be small enough not to reach a hand through.
It might look like a floating chicken coop
but many times a difficult target will be avoided in favor of the easy ones. A piece can also be installed around the upright mast.
The fencing can be easily rolled up and secured to something near the beach with the cabling and locks.
Someone motivated to steal your hardware can still bring bolt or wire cutters but the time involved would favor detection and apprehension.
I would definitely report it and check back with The Authorities to keep it in their minds that it is a problem- maybe go to your local news channel who might be hungry for an expose' on this crime problem? Especially since the city is requesting boaters to use the beach to give an impression to tourists?