SS Dalserf

Also known as: Dalserf

Grassholm is best known for its 36,000 pairs of nesting gannets — the third-largest colony in the world — but beneath the waves on the island's south-eastern flank lies the Dalserf, a Cardiff coal carrier that struck the rocks in July 1910. All 27 crew survived, though the ship did not. Salvors stripped her of non-ferrous metals long ago, but the triple-expansion engine with its distinctive three-cylinder arrangement and the boiler still mark the centre of the site at around 20 metres. The real draw is the setting: diving among boulders beneath a volcanic island ten miles offshore, with gannets plunge-diving into the water around your boat, is an experience that no shore dive can match. Like the Smalls, reaching Grassholm requires settled conditions and a skipper who knows the reef, so each successful dive here feels properly earned.