Shaw, Savill and Albion ran passenger and cargo services between New Zealand and the UK via the Panama Canal.

[3] Waiwera, Waipawa and Wairangi had capacity for just over 522,000 cubic feet (14,781 m3) of refrigerated cargo,[4] berths for 12 passengers and a deadweight tonnage of more than 13,000.

[5] Their Burmeister & Wain marine diesel engines, which Harland and Wolff built under licence, gave them a speed of 17 knots (31 km/h).

On 5 June 1942 Waimarama left Cristóbal at the Caribbean entrance of the Panama Canal in Convoy CS 5, which took her as far as Key West in Florida.

On 2 August 1942, 14 Allied merchant ships including Waimarama and Wairangi left the Firth of Clyde in Scotland in the heavily escorted Convoy WS 12S.

[13] From 11 August onward German and Italian aircraft, surface vessels and submarines repeatedly attacked the convoy.

Before dawn in the small hours of 13 August, Italian torpedo boats and German E-boats sank four merchant ships including Wairangi.

Then at 0810 hrs Luftwaffe aircraft attacked the convoy[14] east of Cape Bon, Tunisia and south of the Italian island of Pantelleria.

[15] The destroyer HMS Ledbury entered the field of burning débris and, at considerable risk to herself, rescued survivors of both ships from the water.

[20] In February 1943 Waimarama's Master, Robert Pearce, DSC, and his Third Wireless Officer, John Jackson, were mentioned in dispatches "For gallantry, skill and resolution while an important Convoy was fought through to Malta in the face of relentless attacks by day and night from enemy aircraft, submarines and surface forces".

Cadet Treves was awarded the BEM[16] and Lloyd's War Medal for Bravery at Sea[22] for saving the officer who could not swim.

[9] 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 Waimarama under way at sea.