In-flight refuelling trials over Calshot with Short S.30 Empire G-AFCU Cabot. The receiver and the tanker each deployed a cable with a grapnel to establish a line between the two and then the hose could be reeled in by the receiver. 16 transatlantic airmail flights were made by Cabot and G-AFCV Caribou using this method just before the outbreak of the war. Just like the catapult ships used by the Germans, the Harrow tankers did not travel far, but allowed the mailplanes to fly with a heavier fuel load. Photo from: Nationaal Archief (Netherlands)