A <a href="https://en.wikipedia.org/wiki/Dornier_Do_18" class="extiw" title="en:Dornier Do 18">Dorner 18</a> flying boat forced down on the water by a <a href="https://en.wikipedia.org/wiki/Lockheed_Hudson" class="extiw" title="en:Lockheed Hudson">Lockheed Hudson</a> aircraft of <a href="https://en.wikipedia.org/wiki/RAF_Coastal_Command" class="extiw" title="en:RAF Coastal Command">Costal Command</a>. This picture was taken just before it was sunk by machinegun fire, and the first burst can be seen hitting the water astern and beyond the flying boat.
Unknown photographer
War Office via IMS Vintage Photos