Shortage of steel and timber for shed building, and the lack of labour to erect these materials had they been available, rendered other methods necessary. It was resolved to try the experiment of mooring airships in clearings cut into belts of trees or small woods. A suitable site was selected and the trees were felled by service labour. The ships were then taken into the gaps thus formed and were moored by steel wires to the adjacent trees. Screens of brushwood were then built up between the trees, and the whole scheme proved so successful that even in winter, when the trees were stripped of their foliage, airships rode out gales of over 60 miles per hour. The personnel were housed either in tents or billeted in cottages or houses in the neighbourhood, and gas was supplied in tubes as in the earlier days of the stations before the gas plants had been erected. This method having succeeded beyond the most sanguine expectations, every station had one or more of these sub-stations based on it, the airships allocated to them making a periodical visit to the parent station for overhaul as required. Engineering repairs were effected by workshop lorries, provided that extensive work was not required. In this way a large fleet of small airships was maintained around our coasts, leaving the bigger types of ships on the parent stations, and the operations were enabled to be considerably extended. Of course, certain ships were wrecked when gales of unprecedented violence sprung up; but the output of envelopes, planes and cars was by this time so good that a ship could be replaced at a few hours' notice, and the cost compared with building of additional sheds was so small as to be negligible.