I have been concerned about people appropriating the bottom for private use in coastal harbors.
Essentially what you observe is that local jurisdictions have established regulations which govern and control the water / harbor adjacent to their land based jurisdiction. The effect of this is that they sell the right to use a mooring on a seasonal basis, or assign large areas to commercial interests to rent them to others.
What seems to be the case is that local residents not only get first dibs at a mooring, but they get a preferred rate in many cases... a perk for being a tax paying resident. Fine an dandy for those who live in that jurisdiction, but for the land locked they are SOL as far a preferred "rates" or getting pushed up the "waiting list".
Boats need some place to "park" and this is aside from the transients who want to anchor for a brief stay. Where to put all the boats? Many obviously choose the marinas with all their attendant conveniences... showers, pools, car parks, tennis, clubs, electricity, water and bars of course.
Others prefer to be moored off. And the choices for a mooring are now few and far between because their are so many boats that the "market" has stepped up to deal with this.
The rental costs for a typical mooring does not reflect the actual cost. I check Sag Harbor NY recently. Sag Harbor Village
and you can see how bigger boats are charged more for the same size mooring, local residents pay less and have preference.
A mooring is not without cost... the mushroom, the chain, shackles, splices, float and the painter. and some one has to set it and probable maintain it... So there are maintenance costs.
A mooring rig can probably last 5 years and so it can generate income of up to 10- $15,000 in that period. Do you see any market forces as work here? They appear to be cash cows to me.
Imagine have 100 moorings in some harbor like Coecles, or Dering, or Great Salt Pond? I'd say that is a damn good return on investment. And if you go the transient root, you can really cash out at 30-$50 per night.
While I don't expect moorings to be free, there proliferation has turned many general anchorages into paid parking lots and the only available "free" anchor locations are usually way way out in less protected waters, or require on to be a good rower or have a reliable OB for their dink.
I am not certain how these jurisdiction were able to claim the bottom for economic purposes, but they did.
But what if they did nothing? What would happen? Chaos. So they establish mooring regulations and a grid usually and then offer the spots, and the they get into the mooring business and begin policing the harbor and dolling out fines for breaking their "laws". They either sub contract their mooring operations or establish a position of Harbor Master who might do it. They also provide lots of the bottom to yacht clubs and marinas who can offer their members and customers a mooring (for a fee of course).
This entire process is the result of economic success... lots of boats and not enough place to put them. There is a lot of cashing out going on here.
Then you have the property owners whose properties front on the water. They want control of their view in many cases and get it from the jurisdiction. It is not uncommon to see regs prohibiting anchoring within say 500 feet of the shore MHW.
BI is an interesting situation. The Great Salt Pond is rather vast and a great go to destination for boaters. The island also has a rather small population... aside from the seasonal visitors.. so there is effectively lots of parking space for the visitors. Sag Harbor is exactly the opposite - little parking space and lots of locals with boats and not so locals who keep or want to keep their boats seasonally moored there.
Weekends in season in the USA see the musical chair thing where boaters leave their seasonal mooring and head off to anchor or pick up a mooring at some cruising destination. The seasonal mooring is then often rented to a transient since they are not there. Who gets the revenue? Not the seasonal renter. He doesn't get a cut or a credit. The mooring operators make some extra cash for that space... mooring, slip or whatever. of they know you are off for X days... they will rent your space to someone else... and prohibit you for letting some friend use your mooring or space in your absence.
And most prohibit rafting.. even for a little lunch visit in mild weather. It's a definite NO-NO.
In fact America has become the land of NO-NO.