Cachalot-class submarine

USS Cachalot (SS-170) the lead boat of the class
Class overview
Name: Cachalot class
Builders:
Operators:  United States Navy
Preceded by: USS Dolphin (SS-169)
Succeeded by: Porpoise class
Built: 1931-1934
In commission: 1933-1945
Completed: 2
Retired: 2
General characteristics
Type: Submarine
Displacement:
  • 1,100 long tons (1,100 t) surfaced
  • 1,650 long tons (1,680 t) submerged
Length: 260 ft (79 m) waterline, 274 ft (84 m) overall
Beam: 24 ft 1 in (7.34 m)
Draft: 13 ft 10 in (4.22 m)
Propulsion:
Speed:
  • 17 knots (31 km/h; 20 mph) surfaced
  • 7 knots (13 km/h; 8.1 mph) submerged
Range:
  • 11,000 nautical miles (20,000 km; 13,000 mi) at 10 knots (19 km/h; 12 mph)[5] (20,000 km at 19 km/h) surfaced
  • 83,290 US gallons (315,300 L) oil fuel[5]
Endurance: 10 hours at 5 knots (9.3 km/h) submerged
Test depth: 250 ft (76 m)
Complement: 6 officers, 39 men (peacetime); 7 officers, 48 men (war)[5]
Armament:

The Cachalot-class submarines were a pair of medium-sized submarines of the United States Navy built under the tonnage limits of the London Naval Treaty of 1930. They were originally named V-8 and V-9, and so were known as "V-boats" even though they were unrelated to the other seven submarines (V-1 through V-7) constructed between World War I and World War II. An extensive study was conducted to determine the optimum submarine size under the treaty restrictions, factoring in total force, endurance, and percentage of the force that could be maintained on station far from a base, as in a Pacific war scenario.[7] Joseph W. Paige[5] of the Navy's Bureau of Construction and Repair (BuC&R) developed the basic design, but the builder, Electric Boat, was responsible for detailed arrangement; this was fairly bold, since EB had not built any new submarines since finishing four obsolescent boats for Peru. The previous V-boats were all built in naval shipyards. Cuttlefish was the first submarine built at EB's facility in Groton, Connecticut; construction of previous Electric Boat designs had been subcontracted to other shipyards, notably Fore River Shipbuilding of Quincy, Massachusetts.[5][8]

Design

Although externally much like the later "fleet submarines," internally the Cachalots were quite different. Due to pressure from the Submarine Officers Conference,[5] they featured full double hulls adapted from the Kaiserliche Marine's U-135,[5] direct-drive diesel-electric propulsion systems, a separate crew's mess (reinstated thanks to EB's rearrangement of the internal layout; Portsmouth would follow soon after),[5] and considerable space around the conning tower within the large bridge fairwater (which was drastically cut down in World War II when the 3-inch (76 mm) deck gun was relocated forward of the bridge). The 3-inch gun was selected because it was felt at the time that a larger gun would encourage submarine captains to fight on the surface against superior anti-submarine ships; this remained the standard submarine deck gun until early in World War II, when war experience showed that a larger gun was needed. EB relied on electric welding for the hull, while Portsmouth clung to riveting;[5] during the war, the riveted boats would leak fuel oil.[9][10]

The as-built engine specifications were two BuEng-built, MAN-designed M9Vu 40/46 nine-cylinder[1] two-cycle direct drive main diesel engines, 1,535 hp (1,145 kW) each, with one BuEng MAN[1] two-cycle auxiliary diesel engine,[1] driving a 330 kW (440 hp) electrical generator.[11] The auxiliary engine was for charging batteries or for increased surface speed via a diesel-electric system providing power to the main electric motors.

Due to the full double hull design, the external tanks proved too narrow for easy maintenance,[12] and the MAN diesels were a constant headache, demanding re-engining[12] with General Motors-Winton four-cycle 16-258 engines in 1936-38.[13][14] On the other hand, the class made a major contribution to habitability, when Cuttlefish was the first sub fitted with air conditioning,[12] and to effectiveness, being first fitted with the Mark I Torpedo Data Computer (TDC).[15]

Despite the calculation process, size reduction had gone too far with the Cachalots, limiting their patrol endurance.[5] The subsequent Porpoise class were about 300 tons larger, and each succeeding class was incrementally larger than its predecessors through the Gato-class submarines of 1941. After three Pacific war patrols each, the Cachalots were relegated to training duties in September 1942, as numerous Gato-class boats became available.[12]

Ships in class

Name Hull no. Builder Laid down Launched Commissioned Decommissioned Fate
Cachalot SS-170 Portsmouth Navy Yard 21 October 1931 19 October 1933 1 December 1933 17 October 1945 Scrapped 1947
Cuttlefish SS-171 Electric Boat Company 7 October 1931 21 November 1933 8 June 1934 24 October 1945 Scrapped 1947

See also

Notes

  1. 1 2 3 4 5 Alden, p.210.
  2. ↑ Friedman, p. 310
  3. ↑ Alden, p.211.
  4. ↑ Alden, John D., Commander, USN (retired). The Fleet Submarine in the U.S. Navy (Annapolis, MD: Naval Institute Press, 1979), p.211.
  5. 1 2 3 4 5 6 7 8 9 10 Alden, p.38.
  6. ↑ Leton, H.T. American Submarines (Doubleday, 1973), p.37.
  7. ↑ Friedman, pp. 189-193
  8. ↑ Friedman, p. 193
  9. ↑ Blair, Clay, Jr. Silent Victory (Lippincott, 1975).
  10. ↑ Friedman, p. 193
  11. ↑ Friedman, p. 310
  12. 1 2 3 4 Alden, p.39.
  13. ↑ Fitzsimons, Bernard, ed. The Illustrated Encyclopedia of 20th Century Weapons and Warfare (London: Phoebus, 1978), Volume 5, p.509, "Cachalot".
  14. ↑ Friedman, p. 193
  15. ↑ Alden, p.39. This replaced the older "banjo" and "Is/Was" used in S-boats, as described in Ned Beach's Run Silent, Run Deep.

References

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.

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