At the dawn of the 20th Century, as the world was arming itself for the Great War, admirals dreamed of a submarine that could keep up with the fleet. It’s not clear why they had this dream, for visibility from a submarine is notoriously poor, and the crews would have had no way to communicate with the fleet while submerged, but apparently it seemed like a good idea at the time. Since the diesel plants of the day were quite inadequate for this purpose, the Royal Navy turned to steam. The result was the K-class: a 339’ submarine, twice the tonnage of a contemporary destroyer, powered by two 10,500 hp steam turbines turning a pair of big 3-bladed propellers that drove it 24 knots on the surface. Underwater, they used four electric motors powered by batteries charged by a diesel-generator pair – yes, they were hybrids, so they were allowed to use the carpool lane.
The class was every bit as successful as one might expect for a fleet of fragile, ungainly, poorly armed, expensive and difficult to maintain submersible torpedo boats no meaningful scouting ability or communications equipment. The words we’re looking for here are ‘not very’. Range was limited, the view from the bridge was non-existent in any kind of a sea, diving was an prolonged and potentially irreversible process, and when diving at speed, it was all too easy to exceed the boats’ crush depth of 150’. The consequences were predictable. On the last day of January 1918, two squadrons of K-class boats and several light cruisers spent a wild and stormy night running into each other, with considerable loss on life, in what came to be known as the Battle of May Island.
It’s a testimony to the stubbornness and ’can-do’ attitude of the Royal Navy that they built and operated 17 of the vessels between 1917 and 1931. Well, perhaps it’s just a testimony to their stubbornness. Not satisfied with achievement, they followed it up with the M-class submersible cruiser. These unusual vessels, armed with a 12-inch cannon, rank very high on the Whatever Were They Thinking scale. Long range attacks against surface ships firing a single gun from the rolling deck of a submarine without any way to observe the fall of shot must have set new standards for inaccuracy. And the concept of using a submarine for shore bombardment is eccentric, even by English standards.
Not to be outdone, the French replied with the Surcouf (N N 3), the world’s first – and so far it’s only – submersible aircraft carrier. The air wing consisted of one (1) Besson MB 411 floatplane with a top speed of 118 MPH and a combat capability of pretty much zero. It also carried a motorboat because… well… heck, why not? This remarkable vessel was launched in 1927 and vanished sometime in 1942, no one is quite certain how. Wartime records suggest the craft was sunk, but one imagines the crew woke up one morning, looked around their unwieldy behemoth, thought, “Bugger this,” and used the boat’s 11,000 mile range to nip off to some idyllic tropical island.
Faced with these intriguing exercises in technology, it’s hard not to wonder what might have happened, in a world with more ambition and less common sense than ours. Naval combat would never have been the same. One imagines the Alternate Battle of Jutland (“We thought we had them when Jellicoe crossed their ‘T’, but Scheer ordered the German battle line to dive.”) or the Alternate Battle of the Coral Sea (“Scratch one flattop! No, it just surfaced again, darn it.”)