HMS M1 facts for kids

HMS M1 was a special type of submarine built for the Royal Navy in the United Kingdom. She was one of four submarines in her class, ordered near the end of World War I. Sadly, HMS M1 sank in 1925, and all her crew were lost.

HMS M1, painted in a camouflage pattern.
Quick facts for kids History
United Kingdom
Name	HMS M1
Launched	9 July 1917
Homeport	Portsmouth
Fate	Sunk in collision, 12 November 1925
General characteristics
Class and type	M-class submarine
Displacement	1,594 long tons (1,620 t) surfaced 1,946 long tons (1,977 t) submerged
Length	295 ft 9 in (90.14 m)
Beam	24 ft 8 in (7.52 m)
Installed power	2,400 hp (1,800 kW) (diesel engines) 3,200 hp (2,400 kW) (electric motors)
Propulsion	2 × 12-cylinder Vickers diesel engines 4 × electric motors 2 × 3-blade, 5 ft 10 in (1.78 m) diameter screws
Speed	15 kn (17 mph; 28 km/h) (surfaced) 8–9 kn (9.2–10.4 mph; 15–17 km/h) (submerged)
Range	2,000 nmi (2,300 mi; 3,700 km) at 15 kn (17 mph; 28 km/h) 4,500 nmi (5,200 mi; 8,300 km) at 10 kn (12 mph; 19 km/h)
Endurance	80 nmi (92 mi; 150 km) at 2 kn (2.3 mph; 3.7 km/h)
Test depth	200 ft (61 m)
Complement	62
Armament	1 × 12-inch (305mm)/40 cal Mark IX gun with 50 rounds 1 × 3 in (76 mm) Mk II HA anti-aircraft gun 4 × 18 inch (450 mm) bow torpedo tubes with 4 reload torpedoes

About HMS M1

HMS M1 was a very unusual submarine. She was designed to be a "submarine monitor." This meant she was built to carry a huge gun, rather than relying only on torpedoes.

The idea was that a large gun could hit surface ships better than torpedoes. At the time, it was thought that torpedoes often missed ships that were moving, especially from far away.

A Special Submarine Gun

M1 had a massive 12-inch (305mm) gun. This gun was meant to be fired while the submarine was mostly underwater. Only the barrel of the gun would stick out above the surface.

A model at the Science Museum shows the 12-inch (305mm) gun turret.

The gun could shoot very far, up to 15,000 yards (13,700 m). But it was usually aimed using a simple sight, like a bead. It was very important to hit the target with the first shot. This is because the gun could only be reloaded when the submarine was fully on the surface.

In 1923, the gun was damaged. Water leaked into the barrel, causing problems when it was fired.

Size and Home

HMS M1 was 295 feet 9 inches (90.14 m) long. When she was underwater, she weighed about 1,950 long tons (1,980 t). Her home base was Portsmouth, a major port in the UK.

She was launched on July 9, 1917. However, she did not take part in any battles during the First World War.

The Sad End

On November 12, 1925, HMS M1 was taking part in an exercise in the English Channel. She was underwater when a Swedish ship called SS Vidar accidentally hit her.

The collision was very powerful. It tore the large gun right off the submarine's hull. Water quickly flooded into the submarine through the open hole where the gun had been loaded.

All 69 crew members were trapped inside. They tried to escape by flooding the inside of the submarine and opening an escape hatch. Sadly, their bodies were never found. HMS M1 sank to a depth of 70 metres (230 ft).

Finding the Wreck

In 1999, a team of divers led by Innes McCartney found the wreck of HMS M1. It was discovered at a depth of 73 metres (240 ft).

Later that year, another diver named Richard Larn and a BBC TV film crew visited the wreck. They made a documentary about it, which was shown in March 2000. Today, the wreck of HMS M1 is a "protected place" under a special law. This means it is kept safe and respected as a military memorial.