Another reason for the transition from wood to steel hulls is the durability of steel as compared with wood. Referring to the large sums of money that have been appropriated under the head of construction and repairs, for which there is now so little to show (and disregarding the question of administration, which of course is vital, but which has no place in this chapter), the main reason for the deficiency in the results is that all this money has been expended in perishable material. Every ship that has been built of wood since the war has been a mistake. The most serious error was committed when the wooden double-turreted Monitors of the _Miantonomoh_ class were built, which, it is believed, was done against the protest of Captain Ericsson. The result was the early decay of these vessels, and the present defenceless condition of our sea-coast. The lifetime of a wooden ship is of short duration. It requires constant repairs, which amount in the long-run to rebuilding, and it is in this manner that so many of our old ships are still retained in service; but in the case of a wooden armored vessel these repairs are impossible without removing the armor. This was the condition of affairs with regard to these Monitors, and the consequence is that the country has to incur the expense of entirely new constructions. These are in durable material, and will give good account of themselves when called on. The steel hulls that it is now the intention shall compose the fleet, will, if well cared for, endure in perfect condition for thirty years. In fact, the lifetime of an iron or steel hull is not defined to any limit, and if a perfect anti-corrosive and anti-fouling composition can be produced, the limit may be regarded as indefinite. The foregoing remarks on our new navy apply to unarmored cruisers, a class of ships which supply a want in time of peace, but cannot fulfil the purposes of war. At such a time the armored ship is recognized as indispensable, and there is every reason why the construction of armored vessels should proceed simultaneously with that of the unarmored cruisers. These are a more intricate problem for study, need much more time to build, and are required, while at peace, as a school of instruction in which to prepare for war. Our selection of armor has been much assisted by the investigations of others, and we are in a favorable condition to make a decision on this point; and the type of vessel best suited for a cruiser seems to be settled, by the uniform practice of foreign nations, in favor of the barbette.[51]