Mark 27 torpedo

The Mark 27 torpedo was the first of the United States Navy 19-inch (48-cm) submarine-launched torpedoes.^[2] This electrically-propelled torpedo was 125 inches (3.175 m) long and weighed 1174 pounds (534 kg).^[2] The torpedo employed a passive acoustic guidance system and was intended for both submarine and surface targets.^[2] Nicknamed "Cutie" ^[3] by submarine crews, the Mark 27 entered service in 1943 as a defensive weapon.^[4] The torpedo was classified as obsolete in the 1960s.^[2]

Mark 27 torpedo
Type	Acoustic torpedo[1]
Place of origin	United States
Service history
In service	1943-1946[1]
Used by	United States Navy
Wars	World War II
Production history
Designer	Bell Telephone Laboratories
Designed	1943[1]
Manufacturer	Western Electric
No. built	1000[1]
Variants	Mark 27 Mod 4
Specifications
Mass	720 pounds (330 kg)[1]
Length	90 inches (2.3 m)[1]
Diameter	19 inches (48 cm) (21-inch (53 cm) guide rails)[1]
Effective firing range	5,000 yards (4.6 km) (approx. 12 minutes search duration)[1]
Warhead	Mk 27 Mod 0[1]
Detonation mechanism	Mk 11 Mod 2 contact exploder
Engine	Electric[1]
Maximum speed	12 knots (22 km/h)[1]
Guidance system	Gyroscope[1]
Launch platform	Submarines[1]

The Mark 27 was essentially a Mark 24 mine which had been modified for submarine launching in a 21-inch (53 cm) submerged torpedo tube by the addition of 1" (25 mm) wooden guide studs mounted on the torpedo's outer shell.^[1][5]

Modifications and improvements

Mark 27 Mod 4 torpedo
Type	Acoustic torpedo[1]
Place of origin	United States
Service history
In service	1946-1960
Used by	United States Navy
Production history
Designer	Ordnance Research Laboratory, Pennsylvania State University
Designed	1946[1]
Manufacturer	Avco[1] Naval Ordnance Station Forest Park
Produced	1946-1954[1]
No. built	3000[1]
Specifications
Mass	1,175 pounds (533 kg)[1]
Length	125.75 inches (3.194 m)[1]
Diameter	19 inches (48 cm) (with 21-inch (53 cm) guide rails)[1]
Effective firing range	6,200 yards (5.7 km) (12 minutes search duration)[1]
Warhead	Mk 27 Mod 2, HBX[1]
Warhead weight	128 pounds (58 kg)[1]
Detonation mechanism	Mk 11 Mod 2 contact exploder
Engine	Electric[1]
Maximum speed	15.9 knots (29.4 km/h)[1]
Guidance system	Gyroscope[1]
Launch platform	Submarines[1]

The Mark 27 Mod 4 torpedo was designed by the Ordnance Research Laboratory of Pennsylvania State University in 1946 as an improved version of the Mark 27 torpedo.^[1]

Fully compatible with electrical setting fire control systems through the use of the standard 65-pin umbilical cable, this weapon was in service on submarines for about ten years. It was withdrawn from service use in 1960 with the introduction of the Mark 37 torpedo.^{[citation needed]}

See also

• Mark 24 mine