Under authorization from Congress, a program of airship and base construction, together with helium procurement, was accelerated, and by the end of the year, stations were in commission or being built at key points along both coasts and the Gulf of Mexico.
Akron expanded its facilities many fold for the building of new airships, which were flown to the various bases with increasing frequency during the year. Large classes of officers, aviation cadets and enlisted men went into intensified training at Lakehurst and Moffett Field, preparing themselves to man the ships as fast as they were delivered.
The blimps which have been available to the sea-frontier forces have rendered valuable service in patrol and escort missions. Their exact record of performance, including number of submarine sinkings, obviously cannot now be published.
On sighting a submarine, or finding indication of its presence, the tactical doctrine might call either for attack, or to stand by, summoning airplanes and surface craft in for the kill, keeping the enemy under unsuspected surveillance the while, and saving the blimp's own depth bombs for another action.
The airship is capable of carrying on patrol and escort missions day after day under a wide range of weather conditions, going for months at some stations, even in the winter, without missing a day.
Though no detailed summary of airship activities is possible now, it is no secret that, just as in the last war, the submarines avoided attack upon convoys where airships were on guard. The German high command tacitly admitted that this was one type that the U-boats did not want to meet, an enemy immune to its torpedoes, whose presence the sub's under-water detectors did not reveal, and which might appear overhead without warning. Admiral Doenitz, commanding the German submarine force, testified in a press interview to their respect for our blimps.
The battle against the submarines will be long and difficult, and ships will still go down and men will be lost, but the chase will be relentless as long as the menace exists. Airships, non-rigid, have taken their place in that phase of America's war effort.
Little is available in the way of bibliography on lighter-than-aircraft, their history and characteristics. Among the best works dealing with this subject are Captain C. E. Rosendahl's, "What About the Airship?" (Scribner's), and "Up Ship" (Dodd Mead); Captain Ernst Lehmann's "Zeppelin" (Longman's) and Captain J. A. Sinclair's "Airships in Peace and War" (Rich & Cowan, London).