m, and from the fine condition of their hulls at the
present time. Their depreciation with all of these repairs has not
been probably above six per cent. per annum. They will, however,
probably depreciate ten per cent. during the next six years, and at
the age of twelve or fourteen years be unfit for service. The steamers
Washington and Hermann, which had strong hulls, have been run eight
years, and are now nearly worthless. Their depreciation has been at
least ten per cent. The steamers Georgia and Ohio, which Commodore
Perry and other superintending navy agents pronounced to be well-built
and powerful steamers, (_See Report Sec. Navy_, 1852,) ran only five
years, and were laid aside, and said to be worthless. With all of the
repairs put upon these ships, which were admitted to be capable of
doing first class war service, as intended, they depreciated probably
seventeen per cent.; as it is hardly possible that their old iron
would sell for more than fifteen per cent. of their prime cost. These
steamers paid much smaller repair bills than the Collins, and were not
so well constructed, or at so high a cost. American steamers do not,
upon the average, last above ten years; but if they reach twelve or
fourteen, they will pay a sum nearly equal to twice their cost, for
repairs and substitutions. Nor is this all. The life of a steamer ends
when her adaptation to profitable service ceases. She may not be
rotten, but may be so slow, or of so antiquated construction, or may
burn so much more fuel than more modern competitors, that she can not
stand the test of competition.

4. We thus see that not only are the requisite repairs most extensive
and costly, but of such magnitude as to greatly reduce the earnings of
any class of steam vessels. But this is not the last costly
consequence of mail speed. It requires more cautious watchfulness of
the engines, the boilers, the deck, and of every possible department
of the navigation, even including pilotage. It requires also more
promptness and dispatch in every movement, and hence a much larger
aggregate number of men. More men are necessary to keep up high fires;
twice as many men are necessary to pass twice as much coal; twice as
many engineers as under other circumstances are necessary for the
faithful working of the engines, and any accidents and repairs which
are indispensable on the ocean; and a larger number of sailors and
officers is necessary to all of the prompt movements req