The Mark 101 Lulu was an air-dropped nuclear depth bomb (NDB) developed by the United States in the 1950s. It utilized a W34 nuclear warhead, with a yield of 11 kilotons. It was deployed by the United States Navy for the purposes of anti-submarine warfare, in five different models, from 1958 until 1971. Weapons were also stockpiled at overseas allied bases under U.S. Marine Corps guard for use by maritime aircraft of NATO allies, notably at RAF St. Mawgan, Cornwall, UK, for use by Royal Air Force Avro Shackleton aircraft, and Dutch Navy P-2 Neptune and P-3 Orion aircraft. The Mk-101 Lulu was replaced by the multi-purpose B-57 NDB in the mid-1960s. The B-57 was a NDB that could also be used by tactical strike aircraft in a land warfare role. The Mk-101 Lulu had a length of 7 ft 6, diameter of 1 ft 6 in, and weighed 1,200 lbs.

The W34 boosted fission warhead used in the Mk-101 Lulu was also used in several other similar weapons, and a version referred to as 'Peter' was used as a thermonuclear primary in the British Yellow Sun and as 'Python' in the U.S. B-28 weapon.

References
* James N. Gibson, Nuclear Weapons of the United States: An Illustrated History (Schiffer Publishing, 1996): Chapter 12, "Nuclear Anti-Submarine Weapons".
* www.mcis.soton.ac.uk/Site_Files/pdf/nuclear_history/glossary.pdf

B57 NDB
The B57 nuclear bomb was a tactical nuclear weapon developed by the United States during the Cold War.

Entering production in 1963 as the Mk 57, the bomb was designed to be dropped from high-speed tactical aircraft. It had a streamlined casing to withstand supersonic flight. It was 3 m (9 ft 10 in) long, with a diameter of about 37.5 cm (14.75 in). Basic weight was about 227 kg (500 lb).

Some versions of the B57 were equipped with a parachute retarder (a 3.8 m/12.5 ft diameter nylon/Kevlar chute) to slow the weapon in its descent, giving the aircraft a chance to escape the blast (or to allow the weapon to survive impact with the ground in laydown mode) at altitudes as low as 15 m (50 ft). Various fuzing modes were available, including a hydrostatic fuze for use as a depth charge for anti-submarine use.

The B57 was produced in six versions (mods) with explosive yields ranging from 5 to 20 kilotons. Mod 0 was 5 kT, Mod 1 and Mod 2 were 10 kT, Mod 3 and Mod 4 were 15 KT, and Mod 5 was 20 kT. The depth bomb version for the U.S. Navy was 10 kT.

The B57 used the Tsetse primary design for its core design, shared with several other mid- and late-1950s designs.

The B57 was produced from 1963 to 1967. After 1968, the weapon became known as the B57 rather than the Mk 57. 3,100 weapons were built, the last of which was retired in June 1993.

The B57 could be deployed by most U.S. fighter, bomber and Navy antisubmarine warfare and patrol aircraft (S-3 Viking and P-3 Orion), and by some U.S. Navy helicopters.