Both ships were initially owned by Union Cold Storage, a ship-owning company controlled by Blue Star Line.

[1] On 5 October 1940 Melbourne Star was in the North Atlantic between 400 and 500 miles west of Achill Island in Ireland en route from Freetown, Sierra Leone to Glasgow, Scotland, when a Luftwaffe aircraft attacked her with several bombs.

The operation's flag officer, Admiral Somerville, commended the six merchant ships for their "steadfast and resolute behaviour during air and E-Boat attacks" and singled out Captain MacFarlane "who set a high standard and never failed to appreciate directly what he should do".

The London Gazette reported that MacFarlane "set a high standard and it is largely due to his leadership that the operation was successful".

[8] After Operation Substance Melbourne Star returned independently to Gibraltar and then crossed the Atlantic to Trinidad, where she arrived on 17 November 1941.

[9] She seems to have spent Christmas 1941 and New Year 1942 in Liverpool, where she loaded a cargo for South Africa of armoured vehicles, motor transports, artillery, stores and two aircraft.

[12] At 0810 hrs 13 August twelve Junkers Ju 88 bombers attacked the refrigerated cargo ship Waimarama, which was immediately ahead of Melbourne Star.

Waimarama was carrying aviation fuel and immediately burst into flames, showering Melbourne Star with débris including a piece of steel plate 5 feet (1.5 m) long.

[7] The Hunt-class destroyer HMS Ledbury entered the fire and smoke, rescuing 22 men from Melbourne Star and a few survivors from Waimarama.

Twelve hours after entering port a 6-inch (150 mm) shell from Waimarama's cargo was found embedded in the deck above the captain's day cabin.

[3] Half of Melbourne Star's passengers and several of her crew were from Australia or New Zealand, including five junior Royal Australian Navy officers, a RAAF wing commander and a young Roman Catholic priest.

[22] About 0300 hrs on 2 April Melbourne Star was in mid-Atlantic in heavy weather about 480 miles south-east of Bermuda when the German Type IXC submarine U-129 hit her with two[2][23] or three[24] torpedoes, one of which detonated in her boiler room.

From one of the floats able seaman Leonard White replied, giving the ship's true name but claiming she was bound for Panama with "general supplies".

[2][24] A/B White took charge of the party of four survivors and "was responsible for the intelligent planning of the rations and the morale of his shipmates which was excellent at all times".

[24] The plane circled overhead, touched down on the sea nearby and launched an inflatable boat, in which aircraft navigator Lieutenant Knox came over to the Carley float.

[2] A/B White had lost only 15 pounds (7 kg) in weight in 38 days adrift, and on 28 May was passed medically fit to return to duty.

[26] In August 1944 Best, Burns, Nunn and White were all awarded the BEM for displaying "outstanding qualities of courage, fortitude and endurance which enabled them to survive".

[23] The award came too late for Ronald Nunn, who had been killed on 10 June 1944 when the coaster Dungrange, carrying ammunition and fuel oil for the invasion of Normandy, was sunk in the English Channel off the Isle of Wight.

The Admiralty enquiry into the loss of Melbourne Star established that no Portuguese ship answering that description had been anywhere near that part of the Atlantic that day.

It was therefore suspected that this was a Kriegsmarine merchant raider disguised as a neutral Portuguese ship, and that she had passed Melbourne Star's position and course to the BdU.

[30] On 10 August 2012, the 70th anniversary of Convoy MW 12's departure from Gibraltar, MaltaPost issued a 26-cent commemorative stamp bearing a picture of Melbourne Star entering the Grand Harbour.