Launched as motor merchant Rio Hudson of the C-3 type for Moore-McCormack Lines Inc, New York NY. In July 1941, delivered incomplete to the US Navy for conversion to the escort carrier USS Avenger (CVE 2), fitted with 15 aircraft. On 26 Dec 1941, sold to the Royal Navy and commissioned as HMS Avenger (D 14).

At 09.55 hours on 13 Sep 1942, U-589 (Horrer) fired a spread of two torpedoes at HMS Avenger (D 14) (Cdr A.P. Colthurst, RN), escorting the convoy PQ-18 and after 3 minutes 35 seconds two detonations were heard. It is likely that Horrer made his claims as a result of hearing detonations caused by torpedoes from U-408 (von Hymmen), which was attacking the convoy almost simultaneously.

At 04.14 hours on 15 Nov 1942, U-155 fired a spread of four torpedoes at convoy MKF-1Y about 120 miles northwest of Gibraltar and heard three detonations, but was not able to made visual observations. The Ettrick and HMS Avenger (D 14) were sunk and USS Almaack (AK 27) was damaged.

HMS Avenger (D 14) (Cdr A.P. Colthurst, RN) was hit by one torpedo, which ignited her bomb load and blew out the centre section of the ship. She sank within two minutes. The survivors were rescued by HNoMS Glaisdale (L 44) (LtCdr T. Horve) - further search for more survivors proved fruitless.