[1] Originally built in 1918 as SS Edgecombe by the Skinner and Eddy Corporation of Seattle, Washington for the United States Shipping Board, she was transferred to the United States Navy by Executive Order on 29 October 1921, delivered 16 November 1921, converted to a destroyer tender, and commissioned as USS Rigel on 24 February 1922.

During the interwar period she remained in southern California, usually serving as a stationary receiving and headquarters ship for Destroyer Base San Diego.

On the 28th, she continued westward and on 16 May arrived at Auckland to add her equipment and personnel to the repair and construction facilities offered by that port.

Arriving at Nouméa on 14 November, she shifted to Espiritu Santo two days later and contributed her skills to the Guadalcanal campaign.

On 21 June the repair ship arrived in Milne Bay, New Guinea, and on the 22nd Rear Admiral Daniel E. Barbey, Commander, 7th Amphibious Force, raised his flag.

For the next 61⁄2 months Rigel remained at Milne Bay, repairing ships from LSTs, LCIs, and MTBs to tankers, cruisers, and battleships.

Again bringing her vital equipment and trained men closer to the front, she moved to Cape Sudest, thence proceeded to Buna where her crew continued their round-the-clock schedule from 13 January until 9 June.