German sinkings peaked in spring 1917 before escort allocation and convoy organisation began reducing the campaign's effectiveness. The Henderson Report helped justify convoy adoption, and protection extended to coastal traffic as well as ships crossing the Atlantic. Merchantmen nevertheless had to wait for one another, form up, and proceed at a common pace rather than sail as soon as they were loaded. Survival therefore came with a real loss of transport efficiency that the wider economy had to absorb.
Notable Point · 16:53-18:44
Convoys cut losses but slow the shipping system
Follow the 1917 decline in submarine sinkings and the logistical costs imposed by convoy assembly and common speed.