Reported in Scientific American, This Week in World War I: April 10, 1915

German submarine rescue ship and mobile dry dock “Vulkan,” built in 1912. Image: Scientific American, April 10, 1915

The United States submarine F-4 was launched in January 1912, and foundered in March 1915 near Honolulu in 300 feet of water, with the loss of all 21 crew. This disaster was a stern reminder, if any was needed, that this relatively new technology could be fantastically risky.

The issue of Scientific American from April 10, 1915, pondered the kinds of technology that might help in not only the development and testing but the rescue of submarines in distress. Accidents had already been common enough in Europe: some 30 separate incidents resulting in 300 deaths. Germany, France and Italy had constructed large ships for rescuing or testing submarines destined for service in their own nascent underwater fleets.

Interior of the French rescue ship in 1915. It was capable of lifting 1,000 tons. Image: Scientific American, April 10, 1915

The German ship Vulkan was built in 1910, and was capable of lifting 500 tons. The plan was to have divers attach cables on to or around sunken submarines that could then be lifted up into the cavity in the boat. A wooden floor could be added under the rescued vessel. Given that German submarines had been quite successful, despite being few in numbers, this comment from the article is not surprising: “This mobile dry dock has undoubtedly been of great value during the present hostilities.” The French ship could lift a mass twice as large. The Italian vessel Laurenti was more of a floating dock and pressure chamber that could—in theory, anyway—pressure-test submarines.

Mobile dock “Laurenti”—an Italian design. The interior of the dock was supposed to act as a large pressure chamber for testing submarines, and the vessel was also designed to act as a mobile crane. Image: Scientific American, April 10, 1915

Our full archive of the war, called Scientific American Chronicles: World War I, has many articles from 1914–1918 on submarines. It is available for purchase at