Seaplanes have the advantage of attack in that they are able, on sighting a submarine on the surface, to come down volplané from the clouds, the first intimation of their presence being given by the roar of their engines as they level off close alongside. Submarine "E 4" was nearly caught in this way once near Hiorn's Reef. She had just come to the surface for a look round and to get latitude observations. Lieut.-Commander Julian Tenison, her captain, was sitting comfortably on the bridge-rail while the tanks were being blown below in order to give the boat convenient buoyancy. The seaplane had dived down on him in the path of the sun, and the _rip r.r.rip-room_ of the switched-on engines 200 yards away brought Tenison to his feet with a jump. He realised instantly that there was no time to get under before the enemy could let go his bombs--the change from blowing to flooding tanks would take far more than the usual 30 seconds which suffices to submerge a boat under normal conditions. He reached down, pressed the button of the "diving-hooter," and then stood up and enthusiastically waved his cap to the seaplane pilot. The pilot shot past at a few yards' range, giving a half-hearted wave in return, as a man responds to a perfect stranger who salutes him in the street. As the machine passed, Tenison jumped down below and pulled the lid to: the short delay had been enough for the blows to be shut off and the vents to be thrown open, and the boat was starting under. Through the periscope, before the hull was down, he saw the machine turn ahead of him, coming round on a wing-tip, and evidently now fully awake to the situation. The boat drove under, and at eighteen feet three bombs burst on the surface in quick succession over the forepart of the hull. Being the usual small bombs no damage was done, but had they struck the hull while it was still above water the chances for "E 4" would have been poor. It is quite possible that the German pilot has not to this day seen anything amusing in the incident.