HMS G12

HMS G12 was a British G-class submarine built for the Royal Navy during World War I.

Description
The G-class submarines were designed by the Admiralty in response to a rumour that the Germans were building double-hulled submarines for overseas duties. The submarines had a length of 187 ft overall, a beam of 22 ft and a mean draft of 13 ft. They displaced 703 LT on the surface and 837 LT submerged. The G-class submarines had a crew of 30 officers and ratings. They had a partial double hull.

For surface running, the boats were powered by two 800 bhp Vickers two-stroke diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 420 hp electric motor. They could reach 14.25 kn on the surface and 9 kn underwater. On the surface, the G class had a range of 2400 nmi at 16 kn.

The boats were intended to be armed with one 21-inch (53.3 cm) torpedo tube in the bow and two 18-inch (45 cm) torpedo tubes on the beam. This was revised, however, while they were under construction, the 21-inch tube was moved to the stern and two additional 18-inch tubes were added in the bow. They carried two 21-inch and eight 18-inch torpedoes. The G-class submarines were also armed with a single 3 in deck gun.

Career
Like the rest of her class, G12's role was to patrol an area of the North Sea in search of German U-boats. She survived the war and was sold for scrap in 1920.