If I understand correctly, the glaring problem isn't just regulations but funding.
I don't know if you're aware of the Nipigon, a former Canadian warship in the St. Lawrence River in the Rimouski-Neigette—Témiscouata—Les Basques riding. It was sunk back in 2003.
There are a lot of amateur divers in the St. Lawrence, which is an extremely complex river in terms of navigation and currents. Rather than venturing into the very deep and dangerous Empress of Ireland wreck, they sunk a ship to create a training museum for apprentice divers. The boat was secured and everything dangerous, such as ammunition, was removed before the vessel was scuttled in the St. Lawrence. It was a spectacular sight, by the way.
Could that be a solution for some ships? Obviously, not all boats can be salvaged. In some cases, could boats become training sites for divers?