Water-Donkey was the Germans name for their new decoy craft. This dummy U-Boat was hauled by a real submarine by means of a lengthy tow-rope. (1) The hull (2) rides just beneath the surface. Water-donkey and U-boat were connected by electric cable, and on spotting the enemy (plane or ship) the U-boat commander started a sound-machine (3) when the chasing plane or ship picking up the sounds attacks the water-donkey under the impression that it was a genuine U-boat, air was released from (4) and oil from containers at (5). Air bubbles and oil patches were then formed at (6). After the bombs or depth charges begin to fall, the water-donkey released fragments of wreckage from (7) and was sunk by flooded tanks (8). R.A.F. Coastal Commands Successes had forced the Wilhelmstrasse to equip its still-considerable U-boat fleet with new weapons to reduce their under surface vessels vulnerability. Among these was the man lifting gyro-plane in which an observer ascended several hundred feet for reconnaissance purposes and from which he was in constant touch with his base by telephone. German Gyro Plane Aboard the U-boats the gyro-plane was carried in a special container. Most serious of the new threats to the Allies was the Schnorkel, which enabled the U-boats so equipped (right) to extend its under-water endurance very considerably, and prevented the need to surface every night to recharge the electric batteries which supplied the motive power when submerged; also the vessel could cruise submerged on its Diesel power. The Schnorkel device was an extendable air-shaft divided into two sections and projecting well above the surface, one section acting as air intake and the other expelling the exhaust gases. From German sources came reports that hardship and strain in these new-style U-boats were “incomparably greater than ever before.” The Schnorkel Device
