> To my knowledge the only way access has ever been restricted on these
>  wrecks has been by common salvage law or by divers taking a proprietorial
>  stance over them, either because of their commercial or archaeological
>  interests, and then most of the sport diving community honouring that
>  stance through courtesy or ignorance.

That's just about the way it is being done. The two wrecks I mentioned are
listed as follows:

Association:  Diving: Is on the Gilstone Ledges, but only with permission of
salvor-in-possession Jim Heslin of the Isles of Scilly Underwater Centre.
30,000 coins recovered since relocation of wreck by sport divers in 1967.
Nearly 1000 coins found each year, although many are very worn. Most
discovered in crud near iron cannon among boulders in gullies, which can
plunge to more than 40m. Stern has yet to be found. Beware rough water and
big swells on Gilstone.

Frau Metta Catharina von Flensburg:   Diving: In 1973 Plymouth Sound BSAC
found bell on top of mud blanket over wreck. Holds revealed to contain
hundreds of reindeer
hides in excellent condition. Hides are now turned into shoes, handbags,
belts and other goods to fund continuing excavation. Dived only with
permission of Ian Skelton, project leader, and Glen Peacham, Plymouth Sound
Diving Officer, on look-but-no-touch basis.

The RIMAP group out of Newport, RI also used an Admiralty salvage claim in
filing with the state of Rhode Island on the American Revolution wrecks in
Newport Harbor. They are restricted the same as the Frau Metta Catharina von
Flensburg - look-but-no-touch.

Pete Johnson