Bolster class rescue and salvage ship

USS Conserver (ARS-39) Off Oahu, Hawaii, 26 April 1967
General characteristics
Class and type:	Bolster-class rescue and salvage ship
Tonnage:	1,441 Tons
Displacement:	1,497 long tons (1,521 t) (lt), 2,048 long tons (2,081 t) (fl)
Length:	213 ft 6 in (65.07 m)
Beam:	39 ft (12 m)
Propulsion:	diesel-electric, twin screws, 2,780 hp.
Speed:	15 knots (28 km/h)
Complement:	100
Armament:	two 40 mm guns

Bolster Class ship was designed and built for the U.S. Navy during World War II. Rescue and salvage ships such as the ARS-38 Bolster Class save battle damaged combat ships from further damage and tow them to safety. Rescue, salvage and towing ships provide rapid fire fighting, pumping, battle damage repair and rescue towing to warships in combat and tow them to repair ships or bases in safe areas.

The Basalt Rock Company’s Steel Division built all six of the vessels in the Bolster class. The company was located south of Napa, California, on the Napa River. As the name suggests, the company had originally started in 1920 as a rock quarry operation, but by 1938, it had begun constructing its own barges.

The U.S. Congress passed legislation on 24 October 1941 establishing the Naval Salvage Service. After the attack on Pearl Harbor, the legislation allowed the navy to begin salvage operations through a contract with Merritt-Chapman and Scott on 11 December 1941. In addition, it allowed the U.S. Navy to have Merritt-Chapman and Scott train future naval salvage operators. A salvage crew’s main job was to augment damage control beyond the capacity of the ship’s crew. This could include fire fighting, towing ships to repair facilities, and clearing harbors of scuttled ships and vessels targeted in combat. The U.S. Navy quickly learned that it was far faster to repair a damaged vessel than to construct a new one. During the island-hopping campaigns of the Pacific in World War II, for example, salvage crews cleared the beaches of landing craft while also retaining many of the damaged ones for repair. The craft and their cargoes could then be used in future operations, but, more importantly, the beaches were cleared for additional assault waves as the beach heads became staging areas. The U.S. Navy designed and ordered the Bolster class, which was a group of salvage ships. The navy’s own Bureau of Construction, along with naval officers and the salvage industry, developed this new class during World War II. The salvage ships were sturdy, oceangoing tugs equipped with diesel-electric propulsion units and strong, auto-tensioned towing winches. The U.S. Navy modeled the Bolster class on the Diver salvage-ship design. The key difference between the two types of salvage ships was that the Bolster class had 5' longer beam, which made it more stable and allowed it to carry more equipment. Otherwise, the Bolster and Diver classes were identical.

Crew size was about 120 men including the complement of divers, made complete with some unique features found onboard. Two fire monitors, capable of pumping out 4000 gallons of water per minute onto a flaming deck, aided in rescue efforts. A full machine shop allowed patches to be cut and assembled, repairing damaged hulls long enough to return to port for any major repairs. The forward boom could lift up to 20 tons while the one aft, on the fantail, had a maximum lift of 8 tons. Also on the fantail was the Almon Johnson Towing machine which held 2100 feet of 2 inch wire rope capable of a maximum pull of 50 tons. Further, in her salvage holds was an extensive inventory of portable salvage equipment- pumps, generators, and welding machines of various sizes that could be placed wherever needed. Plus, eight complete legs of beach gear, each capable of generating up to 60 tons of pulling power, were maintained onboard. The ships could lift up to 150 tons off the bottom of the ocean with its main bow rollers and an additional 30 tons on its auxiliary bow rollers. A recompression chamber was available for treating diving related sicknesses and the MK-5 Surface Supplied Diving System was in use.