"Seabee operations in the North Atlantic began early 1942. The first were in Iceland, Newfoundland, and Greenland. These airfields and ports supported Allied convoys. To complete the defensive line these bases made, Seabees were sent to Londonderry, Northern Ireland, Lough Erne, Loch Ryan, and Rosneath, Scotland. Depots, fuel farms, and seaplane bases were constructed to anchor the line. Afterwards the Seabees went South for Operation Overlord preparations. They built invasion bases from Milford Haven to Exeter and prepared for their own multifaceted D-day role."