On 31 May 1940,
Sundowner was requisitioned by the Admiralty to sail to Dunkirk to assist in the evacuation. Lightoller, aged 66 and retired, volunteered to take her, along with his eldest son Roger, and Gerald Ashcroft, an 18-year-old
Sea Scout. Leaving the
Port of Ramsgate at 10:00 on 1 June, the yacht crossed the Channel in company with five other ships. On their way, they rescued the crew of the motor cruiser
Westerly, which had broken down and was on fire. On arrival at Dunkirk, Lightoller realised that the
piers were too high, and so drew alongside the destroyer and started to take on soldiers. Seventy-five men were crammed into the cabin, and another fifty-five on deck, a total of 130.
Sundowner then returned to Ramsgate, avoiding fire from enemy aircraft through evasive manoeuvres on the way, though the greatest danger was being swamped by the wash from fast-moving destroyers. After disembarking the troops, she was preparing to return for France for another load, but by then only ships capable of doing 20 knots were allowed to continue.
Sundowner remained in service as a coastal patrol vessel in the
River Blackwater, Essex. She then moved to the
River Clyde under the control of 647 Transport Company,
Royal Army Service Corps. She was released from service in 1945, and after a refit was returned to Lightoller in 1946, and once again used as a family boat. == Post-war ==