Havmanden-class submarine (1911)

The Havmanden class was a class of six submarines built for the Royal Danish Navy from 1911 to 1914. Also later known as the A class, the boats were designed by the Austro-Hungarian firm Whitehead & Co. of Fiume. The first three submarines were built by the company, while the remaining three were constructed under license in Copenhagen. The boats were just over long and their armament consisted of two bow torpedo tubes, later supplemented with an machine gun. The boats had a single shaft and were propelled by a Fiat or M.A.N. diesel engine on the surface and two electric motors while submerged. Although there was at least one close call for the class leader during World War I, none of the six boats was sunk in service. All six boats of the class remained active in the Royal Danish Navy from their time of construction until 1928, when the first two boats were stricken. The remaining boats were all stricken by 1932. The Havmanden class served as the basis for the Austro-Hungarian Navy's s built during World War I. After taking delivery of its first submarine—the problematic , built at La Spezia by Fiat-Laurenti in 1909—the Royal Danish Navy looked for a submarine design that could be built in Denmark. In 1910, the Navy contracted with Whitehead & Co. of Fiume for the class' namesake boat, , to be built by Whitehead, and plans for a second, , to be built at the Copenhagen Navy Yard. In May 1911, while the first two were still under construction, the Navy ordered two more boats from Whitehead, and , and plans for a final two, and . The Havmanden-class boats were submarines that displaced surfaced and submerged. The boats were long with a beam of and a draft of . For propulsion, they featured a single shaft, a single Fiat or M.A.N. diesel engine for surface running, and twin electric motors for submerged travel. The diesels of the Whitehead boats were rated at , while the Copenhagen boats were . The boats were equipped with two bow torpedo tubes of , but had no deck guns. In 1917, all were outfitted with a single machine gun.