National Geographic : 1925 Jan
TIE NATIONAL GEOGRAPHIC MAGAZINE N;g Photograph by International GOING ABOARD AT THE NORTH ISLAND AIR STATION : SAN DIEGO Three of the officers are being hoisted to the top of the 173-foot mooring mast (see also illustrations, pages 17 and 19) to board the ship for its northern cruise along the Pacific coast. Storms and head winds caused this trip to be prolonged for more than 57 hours, in cluding the time consumed at Tacoma to avoid the valving of helium. for each landing. Consequently, advan tage is taken of Nature's changes. Land ings are made at night, when the ship is cool and heavy, and departures well after sunrise, when the gas is superheated and light. The gas is extremely sensitive to tem perature. Frequently, even as late as midnight, when the ship drops within 300 feet of the ground and the engines cannot be used to drive it farther, it bounces up again like a rubber ball, from the heat still in the earth. Temperature of the ground, in addition to wind velocity and direction, is always ascertained before at tempting a landing. To make a landing, acrewof200or300 men is needed to hold the ship down. To make a mooring at a mast, a dozen men on the ground are suf ficient to couple the two cables and start the machinery. To leadashipoutofa hangar requires the same ground crew of several hundred. To cast off from a mast, the only assistance re quired from outside is to uncouple the gas, fuel, and water pipes and snap back the clamp holding the ship's nose. The engines help to drive the ship down until it is within a certain distance of the ground. If it is go ing directly to the mast, a steel cable is dropped, which the men below couple to one from the top of the mast; the ship rises again and a dummy engine pulls its nose down to the mast. If the ship is going to land on the ground, ropes are dropped, and the ground crew swarms on them like flies as soon as they are within reach. A trained crew is re quired. In the fraction of a second that the ship is stationary-the infinitesimal pause be tween the time engines are driving it down at 45 miles an hour and the buoy ant gas starts to shoot it up again-dozens of men must grab the rope and hang on. A second too early would knock them over, as if catching an express train, and an instant too late would skyrocket them heavenward.