1918 MINNETONKA. The 13, 528 ton British ship ‘Minnetonka’ was en route from Port Sai to Marseille on January 30 1918 when she was torpedoed by a German submarine and sank south of Sicily. Previously listed in Hoggarth & Gwynn as an unidentified ship, Robin Gwynn, after further research has now confirmed that it was the Minnetonka that was sunk and that she was carrying mail. This registered cover is from ‘B. B. OFFICE 2 JAN 1918 (Basra Base) and has a boxed ‘DAMAGED BY IMMERSION / IN SEA WATER’ violet cachet. A rare cover, one of only two known.