The navy’s bureau of construction and repair undertook the work of making seaworthy again the hundred and more German ships in our harbors when war was declared which had been seriously injured by their crews, under orders from the German government. So much damage had been done, especially to the cylinders, that the enemy had thought, according to memoranda left behind, it probably could not be repaired at all and certainly not within a year and a half. Officers of the navy, in the face of opposition by engine builders and marine insurance companies, determined to make the repairs by means of electric welding, the use of which on such an extensive scale was unprecedented. The experiment was successful and these great ships were in service within six months, the navy’s engineering feat having thus saved a year of time and provided means for the transportation of half a million troops to France. The naval gun factory at Washington was enlarged to double its output. The navy powder factory and the Newport torpedo station had their capacity greatly increased and a large new mine-loading plant was constructed. A big projectile factory was begun in the summer of 1917, and the buildings were finished, the machinery installed and the plant in operation in less than a year. Within a year and a half the work of the ordnance bureau of the navy increased by 2,000 per cent, its expansion including the gun, powder and projectile factories mentioned above. Plants for various purposes taken over by the bureau from private industry increased their output at once by large percentages, in one case, in which the product was steel forgings, 300 per cent. The depth bomb proved one of the most efficient means of fighting the submarine. It contains an explosive charge fitted with a mechanism which causes explosion at a predetermined depth under the water. An American type was developed and within a few weeks was being manufactured in large quantities, while manufacture of the British type was continued for their navy. A new gun, called the “Y” gun, was devised and built especially for firing depth charges. It made possible the throwing of these bombs on all sides of the attacking vessel, thus laying down a barrage around it. A star shell was developed which, fired in the vicinity of an enemy fleet, made its ships visible, our own remaining in darkness. Anti-submarine activities made necessary an enormous increase in the manufacture of torpedoes and torpedo tubes, which grew by several hundred per cent and far surpassed what had been thought the possibility of production.