|Builder:||HM Dockyard, Chatham|
|Laid down:||16 December 1912|
|Commissioned:||14 October 1914|
|Fate:||Sold, 7 March 1921|
|Class and type:||E class submarine|
|Length:||181 ft (55 m)|
|Beam:||15 ft (4.6 m)|
HMS E12 was a British E class submarine built by HM Dockyard, Chatham. She was laid down on 16 December 1912 and was commissioned on 14 October 1914. She cost £101,900.HMS E12 became trapped in anti-submarine nets in the Dardanelles. Her forward hydroplanes became entangled which sent her down to 245 feet. At the time, it was the greatest depth achieved by any British submarine. E12 managed to surface only to come under fire by shore batteries. She avoided further damage. HMS E12 was sold in Malta on 7 March 1921.
Like all post-E8 British E-class submarines, E12 had a displacement of 622 tonnes (686 short tons) at the surface and 807 tonnes (890 short tons) while submerged. It had a total length of 180 feet (55 m) and a beam length of 22 feet 8.5 inches (6.922 m). It contained two diesel engines each providing a power of 1,600 horsepower (1,200 kW) and two electric motors each providing 840 horsepower (630 kW) power. Its complement was thirty-one crew members.
The submarine had a maximum surface speed of 16 knots (30 km/h; 18 mph) and a submerged speed of 10 knots (19 km/h; 12 mph). British E-class submarines had fuel capacities of 50 tonnes (55 short tons) of diesel and ranges of 3,255 miles (5,238 km; 2,829 nmi) when travelling at 10 knots (19 km/h; 12 mph). E12 was capable of operating submerged for five hours when travelling at 5 knots (9.3 km/h; 5.8 mph). It was fitted with a 6 pounds (2.7 kg) 6-pounder gun, five 18 inches (460 mm) torpedo tubes, and one spare torpedo tube. Its torpedo tubes were fitted at the front and the aft; unlike pre-E9 submarines, the two midship section torpedo tubes were not included.
E-Class submarines contained wireless systems with 1 kilowatt (1.3 hp) power ratings; in some submarines, these were later upgraded to 3 kilowatts (4.0 hp) systems by removing a midship torpedo tube. Its claimed highest dive depth was 100 feet (30 m) although it was capable of reaching depths of below 200 feet (61 m). Some submarines contained Fessenden oscillator systems.
- Hutchinson, Robert (2001). Jane's Submarines: War Beneath the Waves from 1776 to the Present Day. London: HarperCollins. ISBN 978-0-00-710558-8. OCLC 53783010.
- Innes McCartney; Tony Bryan (20 February 2013). British Submarines of World War I. Osprey Publishing. pp. 11–12. ISBN 978-1-4728-0035-0.
- "E Class". Chatham Submarines. Retrieved 20 August 2015.