fortifications on Sandy Hook, and one of the shoals, might
probably be so constructed as to furnish a pretty sure barrier to the
entrance of this outer harbor; on the other hand, a naval force
stationed within the inner harbor, and acting under the protection of
forts at the Narrows, might also furnish a good, though perhaps less
certain protection for this outer roadstead. Here, then, we might well
consider the question of relative cost and economy of support of the
proposed fortifications, and of a home squadron large enough to effect
the same object, and to be kept continually _at home_ for that special
purpose. If we were to allow it to go to sea for the protection of our
commerce, its character and efficiency as a _harbor_ defence would be
lost. We can therefore regard it only as a local force--fixed within the
limits of the defence of this particular place--and our estimates must
be made accordingly.

The average durability of ships of war in the British navy, has been
variously stated at seven and eight years in time of war, and from ten
to twelve and fourteen years in time of peace. Mr. Perring, in his
"Brief Inquiry," published in 1812, estimates the average durability at
about eight years. His calculations seem based upon authentic
information. A distinguished English writer has more recently arrived at
the same result, from estimates based upon the returns of the Board of
Admiralty during the period of the wars of the French Revolution. The
data in our own possession are less complete; the appropriations for
_building_ and _repairing_ having been so expended as to render it
impossible to draw any accurate line of distinction. But, in the returns
now before us, there are generally separate and distinct amounts of the
_timbers_ used for these two purposes; and consequently, so far as this
(the main item of expense) is concerned, we may form pretty accurate
comparisons.

According to Edge, (pp. 20, 21,) the average cost of timber, for hulls,
masts, and yards, in _building_ an English 74 gun ship, is L61,382. Let
us now compare this cost of timber for _building_, with that of the same
item for _repairs_, for the following fifteen ships, between 1800 and
1820. The list would have been still further enlarged, but the returns
for other ships during some portion of the above period are imperfect:

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Name of Ship. |No. of| When | Repaired from |