Kea Channel

The Kea Channel, between the island of Kea and Cape Sounion on the Attic mainland, was an Allied shipping lane in the First World War and a German minefield at the same time. On 14 November 1916 the French troop carrier SS Burdigala struck a mine laid by U-73 and sank northwest of Kea; seven days later, on 21 November, the hospital ship HMHS Britannic hit the same minefield and went down 55 minutes later with the loss of 30 of the 1,066 people aboard. The two hulls now lie about two nautical miles apart, a First World War memorial that neither island nor divers can easily reach.

The two wrecks sort by depth and by what a team can actually do on them. Burdigala is upright and broken in two, her deck reported between about 53 and 60 m depending on the source and her seabed near 70 m — serious trimix diving but within reach of a strong technical team on a single tank of gas. Britannic is another order of problem: she lies on her starboard side largely intact, her shallowest point reported at 80 to 90 m by early expeditions and her deepest point close to 120 m, so every dive on her runs on closed-circuit rebreathers with staged decompression and a shot line placed section by section rather than a swim end to end.

Access to both wrecks runs through Greece rather than through any dive shop. Since 2003 Greece's Ephorate of Underwater Antiquities has held jurisdiction over any wreck more than fifty years old, so both sites need its permission, and Britannic additionally needs the agreement of British historian Simon Mills, who bought the wreck in 1996 and runs the Britannic Foundation. Both are dived look-only: a technical diver died on Britannic in 2019, and the one sanctioned removal from her — a 2025 recovery of the ship's bell and other artefacts for a new Piraeus museum — was carried out by an 11-diver team under that same permit.