L9 and its successors were enlarged to accommodate
21-inch (53.3 cm) torpedoes and more fuel. The submarine had a length of
overall, a
beam of and a mean
draft of . They
displaced on the surface and submerged. The L-class submarines had a crew of 38 officers and
ratings. For surface running, the boats were powered by two 12-cylinder
Vickers diesel engines, each driving one
propeller shaft. When submerged each propeller was driven by a
electric motor. The boats were armed with four 21-inch
torpedo tubes in the bow and two
18-inch (45 cm) in broadside mounts. They carried four reload torpedoes for the 21-inch tubes for a grand total of ten torpedoes of all sizes. They were also armed with a
deck gun. ==Construction and career==