An item referred to the magazine Marine Rundschau dated January 1939 reporting that the conversions of aged destroyers into aircraft defence vessels criticised because experts doubted if there was a sufficient control of fire possible for this kind of very active ships. For the air defence the harbours of London, England and other cities was proposed to use pontoons fitted out with an anti aircraft armament in stead. The pontoons could at the same time be used as ammunition ships and accommodation ship and anchored nearby the object to be defended. It seems to be that already such pontoons at Whale Island near Portsmouth, England were tested.
