graduate

Tambor Class, U.S. Submarines


Photograph of Tambor-class submarine

U.S. Navy


Specifications:


Tonnage 1475 tons standard displacement
2370 tons submerged
Dimensions 308' by 27' by 13'8"
93.88m by 8.23m by 1.47m
Maximum speed       21 knots surfaced
10 knots submerged
Dive
250 feet
76 meters
Complement 75
Armament 6 21" bow/4 21" stern torpedo tubes (24 torpedoes)
1 3"/50 AA gun
2 0.50 machine guns
Machinery
2-shaft diesel (6400 bhp) or electric (2740 shp)
Bunkerage 175 tons diesel oil (normal)
301.9 tons diesel oil (maximum)
Range 11,000 nautical miles (20,000 km) at 10 knots surfaced
96 nautical miles (180 km) at 2 knots submerged
Cargo 56 tons
Dive time 36 seconds to periscope depth
Sensors
QCD sonar
Modifications
Tambor and possibly some others replaced the 3" gun with a 5"/51 gun in 1943.


The Tambors were completed in 1940-1941 and were essentially improved Sargos.  They established the configuration (six forward torpedo tubes, four rear torpedo tubes, and a total of 24 torpedoes) that characterized all American submarines built during the war. They were the first American submarines designed in light of early experience with the torpedo data computer, and this was placed in the conning tower where the commander could quickly refer to it while at the periscope. The sonar operators were also moved into the conning tower where they could feed data directly to the TDC operator and the commander. This required an enlarged conning tower.

The Tambors were the first submarines equipped with "pencil" periscopes, whose upper portion was just 2.5" (6.35 cm) in diameter to make it less visible.

There was considerable discussion during the preliminary design phase of the gun armament. The Submarine Officers Conference split into small-gun and large-gun camps, the former favoring a 3" dual-purpose gun and the latter an 5" dual-purpose gun. Hart was strongly opposed to the more powerful weapon, believing it would only encourage foolhardy surface actions by submarine commanders, while Lockwood strongly favored the more powerful weapon. The compromise that was reached was to install a 3" gun, but to make the gun foundation heavy enough to support a 5" gun if the need arose to rearm the boats. This took place partway through the Pacific War.

The Tambors also included a negative tank, intended to reduce dive times. This was kept full when surfaced, adding to diving momentum when the main tanks were flooded. The negative tank was blown dry once the submarine was underwater to restore neutral buoyancy. Such a tank (then  called the "down express") was used in the S-48 class but had not been a part of designs since.

The one real weakness of the boats was the single large engine room, which reduced survivability.

No other American submarine class suffered as high losses in proportion to its numbers in the Pacific. Seven of the twelve Tambors were lost, all but two with all hands.


Units in the Pacific:

Gar    

Panama


Grayling

3 days out of San Diego     

Disappeared 1943-9-30 in the Philippines

Gudgeon

Lahaina Roads

Disappeared 1944-6-7 in central Pacific

Tambor

near Wake


Tautog

Pearl Harbor


Thresher

50 miles NW of Oahu


Triton near Wake Sunk by depth charges 1943-3-15 off New Britain
Trout near Midway Likely sunk by depth charges 1944-2-29 in East China Sea
Tuna Mare Island
Grampus Arrived 1942-1-1 Likely sunk by depth charges 1943-3-6off New Britain by Minegumo
Grenadier       Arrived 1942-1-1 Sunk by aircraft 1943-4-22 off Malaya
Grayback Arrived 1942-1-19 Sunk by aircraft 1944-2-27 in East China Sea


References

Alden (1979)

DANFS

Friedmann (1995)

Worth (2001)



Valid HTML 4.01 Transitional