three
miles, but from Dauphin Island a bank of hard sand makes out under
water both east and south, defining one side of the main ship channel,
which closely skirts Mobile Point, and narrowing it to a little less
than two thousand yards. Near the southeast point of this bank there
rise two small islands, called Sand Islands, distant three miles from
Mobile Point. The channel on the other side is bounded by a similar
sand bank running seaward from the Point, the two approaching so that
at Sand Islands they are not more than seven hundred and fifty yards
apart. Vessels of very light draught could also enter the bay from
Mississippi Sound, but it was not practicable for the fleet.

The entrance from the Gulf was guarded by two works, Fort Morgan on
Mobile Point and Fort Gaines on Dauphin Island. The approach by
Mississippi Sound was covered by Fort Powell, a small earthwork on
Tower Island, commanding the channel which gave the most water, known
as Grant's Pass. Gaines was too far distant from the main ship channel
to count for much in the plans of the fleet. It was a pentagonal work
mounting in barbette[22] three X-inch columbiads, five 32-, two 24-,
and two 18-pounder smooth-bore guns, and four rifled 32-pounders;
besides these it had eleven 24-pounder howitzers, siege and for flank
defence. In Fort Powell there were[23] one X-inch, two VII-inch and
one 32-pounder smooth-bore and two VII-inch Brooke rifles; these bore
on the sound and channels, but the rear of the fort toward the bay was
yet unfinished and nearly unarmed. The third and principal work, Fort
Morgan, was much more formidable. It was five sided, and built to
carry guns both in barbette and casemates; but when seized by the
Confederates the embrasures of the curtains facing the channel were
masked and a heavy exterior water battery was thrown up before the
northwest curtain. The armament at this time cannot be given with
absolute certainty.[24] The official reports of the United States
engineer and ordnance officers, made after the surrender, differ
materially, but from a comparison between them and other statements
the following estimate has been made: Main fort seven X-inch, three
VIII-inch and twenty-two 32-pounder smooth-bore guns,[25] and two
VIII-inch, two 6.5-inch and four 5.82-inch rifles.[26] In the water
battery there were four X-inch and one VIII-inch columbiads and two
6.5-inch rifles.[27] Of the above, ten X-inch, three VIII-inch,
sixteen 32-pou