I’ve just been reading about the British K-class submarines, which were introduced in 1917 and served until 1931.
The K-class submarines were steam-powered, a fact which might have sounded warning bells from the very start. And things got worse, not better, as the vessels were launched and went into service.
K13 sank during trials. K1 collided with K4 off Denmark and was deliberately scuttled to avoid capture. One day in January 1918, K17 collided with a cruiser. Then K4 was struck by K6 and was subsequently hit by K7; the sub sank with all crew on board. At the same time K22 (which was in fact the salvaged and recommissioned K13) collided with K14. Thus, within the space of just an hour and a quarter, two of the class had sunk and three others were severely damaged.
During a mock battle in the Bay of Biscay K5 disappeared and was never found. K15 sank at her moorings in Portsmouth. K4 ran aground in 1917 and remained stranded for some time. Only one submarine of this class ever engaged an enemy vessel: its torpedo hit a German U-boat, but failed to explode.
K18, 19 and 20 were re-designated as the M-class. The subs still to be built were all cancelled.