The forested mountains of Kāpiti became practice ground for tropical jungle, its sand dunes resounded to small-arms fire, and its beaches were attacked in practice manoeuvres by landing craft.
June 1943 was a cold wet month, but it was essential to practise landing exercises. On June 20, Operation Marnavex reached a climax south of Kāpiti Island. On USS American Legion were 1600 Marines who had to be carried ashore under fire in 35 landing craft. In a falling tide, every boat went aground close to shore, so that the day was occupied in freeing them.
It was pitch dark and the surf was heavy when the last boat left, carrying the ‘beach party’ of 25 sailors, but the motor went dead. About 11 p.m. a powerful LCM1 attached a thick towline to the landing craft, but when it started for the ship a huge wave overturned the small boat, dumping the men in icy turbulent water. Those picked up by the rescue boats were close to freezing, but next morning nine bodies were found on the beach – one man was never discovered.