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Cachalot-class submarine
USS Cachalot - 19-N-14689.jpg
USS Cachalot (SS-170) the lead ship of the class
Class overview
Name: Cachalot-class submarine
Builders: Portsmouth Naval Shipyard
Electric Boat Company
Operators:  United States Navy
Preceded by: Dolphin class
Succeeded by: Porpoise class
Completed: 2
Retired: 2
Preserved: 0
General characteristics
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)
Installed power: 2x120-cell Exide WLLH29B batteries[1]
Propulsion: • two Maschinenfabrik-Augsburg-Nürnberg (MAN) two-cycle nine-cylinder[2] diesels, 1,535 hp (1130 kW) each
• one MAN four-cycle[2] auxiliary diesel
• 2 × Westinghouse motors, 800 hp (597 kW) each[3]
• 2 propshafts
Speed: 17 knots (31 km/h) surfaced
7 knots (13 km/h) submerged
Range: 11,000 nautical miles (20,000 km) at 10 knots (19 km/h)[4] (20,000 km at 19 km/h) surfaced
• 83,290 US gallons (315,300 L) oil fuel[4]
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)[4]
Armament: • 6 × 21 in (530 mm) torpedo tubes (4 forward, 2 aft, 16 torpedoes)[5]
• 1 × 3-inch/50-caliber gun
• 2 × .30-caliber (7.62mm) machine guns

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 given hull classification symbols 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. Joseph W. Paige[4] 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.[4]

Although externally much like the later "fleet submarines," internally the Cachalots were quite different. Due to pressure from the Submarine Officers Conference,[4] they featured full double hulls adapted from the Kaiserliche Marine's U-135,[4] direct-drive diesel propulsion systems, a separate crew's mess (reinstated thanks to EB's rearrangement of the internal layout; Portsmouth would follow soon after),[4] and considerable space around the conning tower within the large bridge fairwaterdisambiguation needed (which was drastically cut down in World War II when the three-inch (76 mm) gun was relocated forward of the bridge). EB also relied on electric welding, while Portsmouth clung to riveting;[4] during the war, the riveted boats would leak fuel oil.[6]

The external tanks proved too narrow for easy maintenance,[7] and the MAN diesels were a constant headache, demanding re-engining[7] in 1936.[8] On the other hand, the class made a major contribution to habitability, when Cuttlefish was the first sub fitted with air conditioning,[7] and to effectiveness, being first fitted with the Mark I Torpedo Data Computer (TDC).[9]

Size reduction had gone too far with the Cachalots, limiting their patrol endurance,[4] and they were soon relegated to training.[7]



  1. Alden, John D., Commander, USN (retired). The Fleet Submarine in the U.S. Navy (Annapolis, MD: Naval Institute Press, 1979), p.211.
  2. 2.0 2.1 Alden, p.210.
  3. Alden, p.211.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Alden, p.38.
  5. Leton, H.T. American Submarines (Doubleday, 1973), p.37.
  6. Blair, Clay, Jr. Silent Victory (Lippincott, 1975).
  7. 7.0 7.1 7.2 7.3 Alden, p.39.
  8. Fitzsimons, Bernard, ed. The Illustrated Encyclopedia of 20th Century Weapons and Warfare (London: Phoebus, 1978), Volume 5, p.509, "Cachalot".
  9. 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.

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