The surface of the road does not flow back and forth into our driveways as the water in a canal does with a connected
marina. We choose tarmac, paving, grass, chippings, mud, whatever for our bit. The road surface doesn't mix with our
property and we are responsible for making sure that muck or gravel doesn't make its way from our gardens onto the
highway. There are also established penalties, things like ANPR, traffic patrols and charges for storing / driving an
untaxed vehicle on the road that combined are deemed sufficient to deter someone from having a trip out in a SORNed
vehicle.
However, the water in the marina is managed by CaRT so even a boat sitting there is utilising CaRT managed
water without ever travelling out onto the cut. The water is both the thing that floats it and the surface of the
transport network. When a boat sits in a marina that is connected, these two are continuously and inextricably linked.
I once used to moor a small sailboat in a marina outside CaRT's remit. It was behind a tidal river lock and no licence or BSS needed. If you weren't going out to sea though , it wasn't long before you were on waters managed by CaRT and needed
to be licensed. For a small boat able to make it onto the canal network for a peek around, this is where the short term
licences are very useful (aswell as for trail boat owners)
The only way it might be possible for a SORN style option to be
viable would be some form of fully isolated pond. Water and movements would be managed by the marina (although I'm not
sure I'd like to be on a pond with people putting stuff down sinks, showers etc into it). Boats would need to be licensed
again before the marina staff could lift/lock gate them back out into the canal or the open marina. However, once in the
pond the boat could be delicensed. Movements in and out could be communicated and confirmed by the marina to CaRT. But
that whole thing is massive infrasturcture investment and planning that I imagine most marinas and councils just would not
be interested in. As for possible demand, I, as a mooring customer, would have no interest in such a place, even if the
boat hasn't been out for a trip for months and I might save the licence fee in such a place.