Bertie was aboard the troopship HT "Marquette", carrying the 29th Division Ammunition Column and the New Zealand Stationary Hospital, all destined for Salonika in Greece.

On leaving Alexandria, the ship was accompanied by a French destroyer escort, which left the Marquette on the night of 22 October. At 9.15am on 23 October, the ship was hit on the starboard side by a torpedo fired from the German submarine U35. She immediately listed to port and began to sink. Some on board were killed by the explosion, while others were killed by lifeboats which were inexpertly launched - one, for example, fell onto another which was already in the water. The ship sank within 10 minutes, with nurses, soldiers and crew still on board. Many survivors died in the water while waiting to be rescued.

Robin Marriott