The Port Napier was taken over by the Admiralty during its construction and converted to lay mines. After being loaded with her cargo, she dragged her anchor during a gale in the Kyle of Loch Alsh

Loch Alsh

Loch Alsh or Lochalsh is a sea inlet between the isle of Skye in the Inner Hebrides and the Northwest Highlands of Scotland. The name is also used to described the surrounding country and the feudal holdings around the loch...

 on 26 November 1940 and grounded in shallow water. While being unloaded there was a fire in the engine room, whereupon the harbour and towns nearby were evacuated, and she was towed well out into the loch and cast adrift in anticipation of an explosion.

A massive explosion on 27 November, which fortuitously did not set off any of the mines, blew her apart and she tipped over on her starboard side and sank in 20 metres of water with her port side visible at low tide.

In 1955 the Royal Navy took off the steel plating on her port side and removed the mines and 4000 anti-aircraft shells.

The wreck is a popular, if silty, site for scuba diving

Scuba diving

Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....

owing to its relative intactness and shallow location 57°15.98′N 5°41.18′W.