The British held it for less than nine months in all.
During 1777 a number of raids were made by British combined land and sea forces, for the purpose of destroying American depots and other resources.

Taken together, such operations are subsidiary to, and aid, the great object of interrupting or harassing the communications of an enemy.

In so far, they have a standing place among the major operations of war; but taken singly they cannot be so reckoned, and the fact, therefore, is simply noted, without going into details.
It may be remarked, however, that in them, although the scale was smaller, the Navy played the same part that it now does in the many expeditions and small wars undertaken by Great Britain in various parts of the world; the same that it did in Wellington's campaigns in the Spanish peninsula, 1808-1812.

The land force depended upon the water, and the water was controlled by the Navy.
[Footnote 18: This was just below the mouth of the Schuylkill, a short distance below the present League Island navy yard.].