Naval mine ship, HMHS "Britannic", which was the sister ship of the RMS "Titanic." During World War II, the U-boat fleet, which dominated much of the battle of the Atlantic, was small at the beginning of the war and much of the early action by German forces involved mining convoy routes and ports around Britain. German submarines also operated in the Mediterranean Sea, in the Caribbean Sea, and along the U.S. coast. Initially, contact mines (requiring a ship to physically strike a mine to detonate it) were employed, usually tethered at the end of a cable just below the surface of the
Hospital ship a mobile field hospital for rapid deployment to any ocean or coastal location at a speed of 297 knots (550 km/h, 341.8 mph). Work was 90% complete on this model, "Spasatel", but Soviet military funding ceased and it was never completed. Some hospital ships, such as and "Esperanza del Mar", belong to civilian agencies, and as such are not part of any navy. Mercy Ships, an international charity, do not belong to any government. Hospital ships were covered under the Hague Convention X of 1907. Article four of the Hague Convention X outlined the restrictions for a hospital ship: According