Fast vedette¹ and patrol boats are used in all the coastal waters of western Europe. In cooperation with the lookout stations on shore, they guard against seaborne as well as air attacks. One of their chief functions at present is to flash warnings of the approach of Allied air formations that sweep across the continent. The patrol boats go out in great numbers, particularly at night. As sentinels on a watery outpost line, they may prove highly effective in nullifying the vital element of surprise on which any seaborne task force would rely heavily in approaching a well-defended beach.

In addition to the larger units of the fleet, the Germans have also a considerable number of smaller craft available for the dual purpose of antiaircraft and coast defense. Standard types of these smaller vessels are submarine chasers, S- and R-boats (motor torpedo boats and motor minesweepers), Sperrbrechers, and Siebel ferries. The Sperrbrechers and Siebel ferries will be discussed here because they are potentially effective weapons against landing craft.