She was the third ship to be called Tregarthen in the Hain SS Co fleet. The first was a steamship that was launched in 1904, sold in 1911 and renamed.[1] The second was a steamship that was launched in 1913, sold in 1933 and renamed.[2]
Building
In 1936 Lithgows built a pair of steamships in its Port Glasgow shipyard for the Hain SS Co. Trewellard was launched on 16 June 1936 and completed that July.[3] Her sister shipTregarthen was launched on 30 July and completed that September.[4]
Tregarthen's registered length was 432.3 ft (131.8 m), her beam was 56.2 ft (17.1 m) and her depth was 24.8 ft (7.6 m). Her tonnages were 5,201 GRT and 3,067 NRT.[5]
Tregarthen had a single screw. David Rowan and Co of Glasgow built her engines. Her main propulsion was a three-cylinder triple expansion steam engine. Exhaust steam from its low-pressure cylinder drove a low-pressure steam turbine, which in turn drove a steam compressor. Her turbine drove the same propeller as her piston engine. Between them the two engines were rated at 469 NHP[5] and gave Tregarthen a speed of 11 knots (20 km/h).[6]
Tregarthen began most of her westbound Atlantic crossings with the protection of an OB (Outward Bound) convoy.[7] In March 1941 she took part on Convoy OB 293, whose escorts sank two U-boats including U-47.[12]
Loss
On 24 May 1941 Tregarthen left Cardiff carrying 7,800 tons of coal bound for Kingston, Jamaica.[13] Off Milford Haven she joined Convoy OB 327, which took her out into the Atlantic and dispersed on 1 June.[14]
At 2325 hrs on 6 June Tregarthen was in mid-Atlantic when two torpedoes fired by U-48 hit her in the stern. She capsized and sank within three minutes, killing all 42 of her crew and her three DEMS gunners.[13]