T Class Submarines

Ocean-going saddle-tank submarines. Britain's planning after the 1930 London Naval Conference dictated submarine operations would have to follow the Prize Rules of World War I - making anti-mercantile shipping all but impossible if following rules. Therefore, future British submarines would be operated as minelayers, in reconnaissance roles and as anti-warship vessels. The development of better anti-submarine weaponry, coupled with the development of Asdic (Sonar) made it imperative that, in the anti-warship role, the submarine would need to attack its targets at greater ranges and with a large salvo of torpedoes. The T Class arrived with an unprecedented ten forward-firing torpedo tubes. The T Class were first ordered in 1935 and some were still operational with the Royal Navy up until the late 1960s. For a period after the end of the war, along with the 'A' Class and a few remaining 'S' Class, they formed the mainstay of the British submarine flotilla. This class of patrol submarines gave good service during World War Two, but suffered heavy casualties - sixteen being lost. A total of 53 were built and their captains won four Victoria Crosses.

In the first group all the torpedo tubes were positioned to fire forwards but later vessels had an external tube added and the two tubes amidships turned to fire astern. Many boats of the second group were modified for employment in the Far East, by transforming several ballast tanks into fuel tanks, thereby increasing fuel load from 132 to 230 tons, and surface range from 8,000 to 11,000 miles at 10 knots. This increase in range, essential in a theatre where it took a week or more to get from base to operating area, together with increased stores capacity, enabled long patrols to be carried out: the record was achieved by Tantalus with 56 days, 40 of which were in the patrol area.

The construction of a further nine units was cancelled in 1944 and replaced by a similar number of the more modern A-Class, which put more emphasis on long-range patrols in Pacific waters, as the European war, at least in the Mediterranean, was coming to an end.

A T Class boat, alongside a Depot Ship, inboard of two S Class (Stygian is outermost)

The T-Class were especially successful against submarines: 13 boats sank 13 enemy submarines - 6 Italian, 4 German and 3 Japanese.

The early boats were of riveted construction but as the numbers increased so did the use of welding methods. This was to affect the varied modifications carried out on this class between 1951-1956.

First Group

• Displacement: 1,090 tons (surfaced) 1,573 (submerged);
• Length: 275ft
• Beam: 26ft 6ins
• Draught: 12ft
• Speed (knots): 15.25 (surfaced),
  8 (submerged);
• Armament: One 4" gun;
  three .303" ;
• Torpedo Tubes: Ten 21"
  (8 forward, 2 amidships),
  16 torpedoes;
• Complement: 56.

Submarines:

Trident, Tribune, Truant, Taku, Torbay, Tuna.

Losses:

Thetis (1939) and, as Thunderbolt, (1943), Triton (1940), Triad (1940), Thistle (1940), Tarpon (1940), Tetrarch (1941), Triumph (1942), Talisman (1942), Tigris (1943).

Second Group

• Displacement: 1,090 tons (surfaced),
  1,571 (submerged);
• Length: 273ft 6ins
• Beam: 26ft 6ins
• Draught: 12ft
• Speed (knots): 15.25 (surfaced),
  8 (submerged);
• Armament: One 4inch gun;
  one .303";
• Torpedo Tubes: Eleven 21"
  (8 forward, including 2 external,
  2 amidships, 1 aft),
  17 torpedoes;
• Complement: 61.

Submarines:

Thrasher, Trusty.

HMS/M Thrasher

War Losses

Tempest (1942); Thorn (1942); Traveller (1942); Trooper (1943); Turbulent (1943);

Third Group

• Displacement: 1,090 tons (surfaced), 1,571 (submerged);
• Length: 273ft 6ins
• Beam: 26ft 6ins
• Draught: 12ft
• Speed (knots): 15.25 (surfaced),
  8.75 (submerged);
• Armament: One 4" gun,
  one 20mm A.A.;
  three .303" ;
• Torpedo Tubes: Eleven 21"
  (8 forward, 2 amidships, 1 aft),
  17 torpedoes;
• Complement: 61.

Submarines:

Trespasser, Taurus, Tactician, Truculent, Tudor, Thule,
Templar, Tradewind, Tally-Ho, Tantalus, Tireless, Token, Trenchant, Tantivy, Telemachus, Talent, Totem, Thorough, Truncheon, Tiptoe, Trump, Taciturn, Turpin, Tapir, Tarn, Talent (3), Teredo, Thermopylae, Tabard.

War Losses:

P311 (Tutenkhamen)(1943); Terrapin (constructive loss)(1945).

Cancelled Orders:

Theban, Talent (2), Threat, Thor, Tiara, Tasman plus two un-named boats. Of these, at least Tiara and Thor were actually launched but not completed.

At the end of the war, some of the class were well past refitting and were scrapped fairly quickly. Those remaining boats in good condition were ear-marked for modernisation, in a similar programme to the US Navy's 'Guppy' scheme. The earlier boats, with riveted hulls, proved difficult and only five of those were streamlined. They were also refitted with a reduction of two internal bow tubes and the removal of two of the three aft-facing external tubes, leaving six bow tubes and one external after tube. They were given a modern sonar and much streamlining, including a fin-type conning-tower. The periscopes and aerials were enclosed in a fin and again all guns and two external torpedo tubes were removed. Together with a few unmodified boats, the T Class came in a variety of shapes and sizes. The five boats, with their final years shown, were: Teredo (1965), Tapir (1966), Tireless (1968), Talent(1970), and Token (1970).

Between 1950 and 1956, eight of the welded-hull type were completely rebuilt, with hulls cut in two and lengthened, having from 12 to 20 feet added amidships. This enabled them to have extra batteries and diesel electric propulsion fitted. Improved diesel-electric propulsion was also fitted giving a submerged speed of 15 knots maximum. Modern noise reduction techniques were incorporated, new sensors were added, and they were streamlined and given a fin-type conning-tower. There were two versions of streamlining, involving either 12ft or 20ft. In the 12ft streamlined boats, the torpedo tubes were redesigned in the same way as the riveted boats, while the boats with the 20ft addition lost their aft torpedo tubes completely. The eight boats, with their final years shown, and added lengths, were: Totem (1968) 12ft, Thermopylae (1970) 12ft, Trump (1971) 20ft, Taciturn (1971) 14ft, Tiptoe (1971) 20ft, Tabard (1974) 20ft, Truncheon(1977) 20ft, and Turpin (1978) 12ft.

Tradewind was used as an acoustic trials vessel and stripped of all external tubes and gun, while only two were retained, tubes 3 and 4, with the upper and lower pairs, tubes 1 and 2, and 5 and 6 respectively, were blanked off. She finished in 1955.

This still left a few to remain as originally built, until the years shown - Torbay (1945), Tuna (1946), Taku (1946), Truant (1946), Trusty (1947), Tribune (1947), Truculent (lost in 1950), Tantalus (1950), Tantivy (1951), Templar (1959), Taurus (1960), Trespasser (1961), Thorough (1961), Telemachus (1961), Thule (1962), Tactician (1963), Tudor (1963), Trenchant (1963), Tarn (1966), and Tally-Ho (1967).

Peter 'Lofty' Hulme, in New Zealand, a submariner of T Class submarines in the 1940s and 50s, has written an excellent piece about these developments in T Class submarines.