This airship, silhouetted against the afternoon sun might be pacing a peaceful cruiser race through the surf off Long Beach, on the Southern California coast. Or it might be leading units of the mosquito fleet to sea off Cape Cod, to hold an enemy U-boat in check till ships of heavier armament could arrive.
Helium-inflated, fast, long ranged, the modern K-type Navy patrol ship is a far cry from the primitive airships of World War I. They are armed with bombs and machine guns.
In brilliant sunshine, or overcast, in fog or rain or snow, the blimps take off from their bases day after day, on guard against any enemy who may invade the coastal waters. A faint smoke screen, miles distant over the endless waters, may turn out to be a peaceful merchantman—or a vessel with grimmer purpose, seeking the advantage of surprise attack.
The detection of a submarine even on the surface is largely a matter of looking in the right direction at the right time. The open windows on all sides of the airship, without obstruction by wings give it special value in this field.
A submarine submerged is still harder to find as its tell-tale feather is not easy to spot from a speeding plane or from the crow’s nest of a surface craft.
A non-rigid airship throttling down to the speed of its prey, and having the altitude of the airplane, has a much better chance of sighting the submarine, before it can launch its torpedoes.