In preparing her for sea the engineers found it necessary to overhaul, partially redesign and reconstruct many important parts of the _Leviathan's_ engines. As in her case, the most serious typical damage was done by breaking the cylinders, valve-chests, circulating pumps, steam and exhaust units in main engines; dry-firing boilers, and thus melting the tubes and distorting furnaces, together with easily detectable instances of a minor character, such as cutting piston and connecting rods and stays with hack saws, smashing engine-room telegraph systems, and removing and destroying parts which the Germans believed could not be duplicated. Then there was sabotage well concealed: rod stays in boilers were broken off, but nuts were fastened on exposed surfaces for purposes of deception; threads of bolts were destroyed, the bolts being replaced with but one or two threads to hold them, and thus calculated to give way under pressure. Piles of shavings and inflammable material with cans of kerosene near suggested the intention to burn the vessels, intentions thwarted by our watchfulness, while the absence of explosives has been accounted for purely on the ground of the risk which the crews would have run in attempting to purchase explosive materials in the open market. No great amount of damage was done to the furnishings or ordinary ship's fittings. Destructiveness was similar in character throughout all the vessels and involved only important parts of the propulsive mechanism or other operating machinery. We have spoken of the investigation of the vessels by Shipping Board engineers. They were appointed by the board not only to make a survey, but to superintend repairs. The collector of the port of New York also named a board of engineers (railroad engineers) to investigate the damage done the German ships, and to recommend repairs through the agency of welding. The railroad men, after due study, believed that their art could be applied to as great advantage on ships as upon locomotives. The Shipping Board engineers recommended, on the other hand, the renewal of all badly damaged cylinders. The railroad engineers, on the other hand, set forth their opinion that all damaged cylinders could be reclaimed and made as good as new. As a result of this difference of opinion, nothing was done until the larger German craft were turned over to the Navy Department to be fitted as transports, in July of 1917. It was then decided to use welding and patching on the vessels. In no cases were the repairs to the propulsive machinery delayed beyond the time necessary to equip these ships as transports. Electric and acetylene welding is not a complicated art in the hands of skilled men; for patching a hole, or filling the cavity of a great crack in a cylinder, say by electric welding, may be compared to a similar operation in dental surgery.