Gato class

Gato class
USS Gato (SS 212)
Overview
Type	Diesel submarine
units	77 built 0 active 6 museum ships 20 war losses
1. Period of service
period of service	1942 to 1966
Technical specifications
displacement	1,526 ts surfaced, 2,424 ts submerged
length	95.33 meters
width	8.30 meters
Draft	4.65 meters
Diving depth	90 m test depth 140 m maximum depth
crew	60-70
drive	4 × diesel engine each 1,350 PS (5,400 PS total output) 4 × electric motor each 685 PS (2,740 PS total output)
speed	20.25 knots (surfaced) 8.75 knots ( surfaced )
Range	48 h immersed (at 2 knots) 75 days patrol
Armament	6 × 533 mm front torpedo tube 4 × 533 mm rear torpedo tube 24 torpedoes 1 × 76.2 mm deck gun 2 × 12.7 mm machine gun 2 × 7.62 mm machine gun

The Gato-class was a class of submarines in service with the United States Navy that were used during World War II . From the Gato class - the name of the class was derived from a smaller subspecies of the cat sharks (English: catshark , colloquially also called dogfish or gato ) - the classes Balao and Tench later emerged. All boats of this type were named after fish. With over 70 units built, this class was the second largest submarine type in the history of the United States Navy in terms of the number of boats built (after the Balao class with 128 units).

history

The boats were an improvement on the units of the previous Tambor class . Above all, the propulsion systems were improved, which allowed the boats to patrol longer. Inside the boats, the living conditions of the crew were improved (see below). The 77 boats in the class were built in less than three years. The first unit, the Drum , was laid down on September 11, 1940 (commissioned on November 1, 1941); the namesake, the Gato , was put into service a little later, on December 31, 1941. The builders were the Portsmouth Navy Yard , Manitowoc Ship Building Company , Electric Boat Corporation, and the Mare Island Navy Yard .

With a few exceptions, all submarines of this class operated in the Pacific theater of war against Japanese shipping from the early summer of 1942 . The boats of the Gato class, together with the boats of the Balao class, which, however, did not join the fleet until mid-1943, carried the brunt of the US tonnage war against Japan. As with the German submarines in the Atlantic Battle , it was a so-called unrestricted submarine war . As early as 1942, US submarines sank more than 600,000 GRT Japanese merchant shipping space; in the course of 1943 this figure rose to over 1.3 million GRT. A total of 17 units of the Gato class were lost during the war due to enemy action, three other submarines were lost for reasons that were not precisely established (possibly mine hits or accidents) and are considered lost.

After the war, 23 boats were transferred to the reserve fleet , some of which were later assigned to the Greater Underwater Propulsion Power Program . These remained in service until 1969. Two boats were converted into Ship Submersible Guided Missiles as test ships in 1946 . In addition, the US Navy gave several units to allied states in the 1950s, two boats each went to Italy , Turkey , Greece and Brazil ; Another boat, the Mingo , was also handed over to the former enemy Japan in 1955 and remained there (under the name Kuroshio ) until 1966. In 1951/52 six boats were converted into radar outpost submarines (SSR) as part of the Migraine III program . Today six boats are still preserved and exhibited in the USA as museum ships .

Technology and equipment

The Gato- class submarines were a maximum of 95.33 meters long and 8.30 meters wide. When surfaced, the draft was 4.65 meters. The hull - all two-hulled boats  - was divided into eight watertight compartments. According to the planning specifications, the regular crew strength was 60 men, but in later years of the war it increased to up to 90 men in some cases due to increased air defense and the radar equipment.

Special features and equipment

The regular diving depth of the boats was 300 feet (approx. 91 meters). The maximum diving depth in an emergency was 450 feet (approx. 140 meters). The Gato- class boats, relatively large compared to their German or some British counterparts, needed a comparatively long time (around 60 seconds) to descend to periscope depth . Experienced US crews achieved diving times of 35 to 40 seconds in later years of the war, which means that the diving time was still longer than, for example, with the (much smaller) German Class VII submarines . Since the Gato- class boats were designed for the expanses of the Pacific region , i.e. also in tropical waters and were to be used over longer periods of time and distances, all units had air conditioning , seawater desalination systems and washing machines for the clothing of the crew. There were also freezers for perishable food on board. In addition, all crew members had their own bunk , which was not the case with German and British submarines.

Armament and sensors

The armament of the Gatos consisted of a deck gun on the upper deck, with this cannon mostly located behind the tower structure, and initially two machine guns each in caliber 12.7 mm and 7.62 mm on platforms on the tower . Some of the machine guns were exchanged for 20 mm Oerlikon cannons in the course of the war . The caliber of the deck gun was either 3 "/ 50 caliber (76.2 mm, Mark 18) or 4" / 50 (102 mm, Mark 9) or 5 "/ 25 (127 mm, Mark 17). The latter cannon was only installed in a few rare cases (such as on board the Haddock ). The deck armament therefore varied considerably from boat to boat (see note). In addition, each boat had ten torpedo tubes, six in the bow and four in the stern, with a diameter of 21 inches (533 mm). Each boat carried a total of 24 torpedoes. Optionally, up to 40 sea ​​mines could also be added, although the number of torpedoes then had to be reduced.

The units of the Gato class were also equipped with radar . From the summer of 1942 onwards, the boats had on the one hand an air warning radar (type SD ) with a range of around 20 kilometers and on the other hand a surface search radar (type SJ , also SJ-1 radar) to detect and combat surface targets. The latter, working on a 10-centimeter wave, could pick up individual merchant ships up to a distance of about 15 kilometers and convoys even up to about 17 kilometers away; larger warships, such as aircraft carriers , are said to have been detected up to a distance of almost 23 kilometers.

Machine system

There were two diesel engine rooms and one e-engine room on board. The main propulsion of the Gato class consisted of four diesel generators, either from the Cleveland Diesel Engine Division (a subcontractor of General Motors ) or from Fairbanks Morse (these being the boats with the designations SS-228 through SS-239 and SS-275 to SS-284), and four electric motors from Elliott Company , General Electric, or Allis-Chalmers . When sailing above water, the diesel engines supplied the boat and the two electric motors with electricity. Two batteries with 126 cells each were available underwater for this purpose, which were charged by the diesel generators while driving over the water. The two propellers had around 5,600 hp (diesel engines) or 2,740 hp (electric motors). This enabled the units to reach a top speed of 20.25 knots (approx. 37.5 km / h) on the water surface and 8.75 knots (approx. 16 km / h) when diving. The range on the surface was about 11,000 nautical miles at ten knots , and submerged the boats could operate at two knots for about 48 hours. The regular patrol time was 75 days.

Individual evidence

1. ↑ The armament varied considerably from boat to boat. Some units also had a 102 mm or even 127 mm deck gun. In addition, the 12.7 mm machine guns were exchanged for 20 mm Oerlikon cannons on almost all boats during the war. Sometimes a 40-mm Bofors cannon also came on board. The armament given here corresponds to the original planning specifications.
2. ↑ NavSource Online: Submarine Photo Archive. Retrieved April 10, 2020 . 
3. ↑ Marc P. Parillo: The Japanese Merchant Marine in World War II. Naval Institute Press. Annapolis (MD) 1993, pp. 37f.
4. ↑ Parillo: Merchant Marine. P. 37f.
5. ^ John D. Alden: The Fleet Submarine in the US Navy: A Design and Construction History. Naval Institute Press. Annapolis (MD) 1979, p. 88.
6. ↑ VII C - U-Boot-Archiv Wiki. Retrieved April 10, 2020 . 
7. ↑ RADAR OPERATORS 'MANUAL - Part 4. Accessed April 10, 2020 . 
8. ↑ http://www.cnrs-scrn.org/northern_mariner/vol14/tnm_14_3_27-40.pdf

Web links

Commons : Gato class  - collection of images, videos, and audio files

• Gato class on globalsecurity.org (English)