Monitors aground: A recurring theme at the entrance to Charleston harbor

Earlier today I wrote about the grounding of the USS Lehigh, 150 years ago this evening.  Observers in Fort Moultrie reported the ironclad was 2,300 yards distant the following morning.  So the general location of the Lehigh when grounding is depicted in the blue circle here:

Lehigh1

You may recall that on September 7, 1863, the USS Weehawken grounded very close to that location:

WeehawkenBattle

In the case of the Weehawken, the tide force the monitor into shallow water.  And those were not the only such groundings at the mouth of Charleston harbor.  Just a few days before the Lehigh‘s grounding, the USS Catskill suffered a similar episode.  On the night of November 5, 1863, Lieutenant-Commander Greenleaf Cilley moved the Catskill up the main ship channel on picket duty.   He reported:

In going towards our station on the night of the 5th, this vessel grounded at 6:40 p.m. about 250 yards to the southward and eastward of Wagner buoy, having 14 and 15 feet of water all around and the least water obtained by sounding around the vessel in a boat was 13 feet, which was about a length from our position toward Fort Wagner.  We appeared to be hung in the center of the ship, as we would swing 12 or 15 points from the northward to east and southward. I made general signal 16, and two tugs came to my assistance.  They pulled and tugged without avail until after 10 p.m., when suddenly we shot off and were afloat.  Left a small buoy to mark the shoal.

Cilley continued to his assigned station and, other than the grounding, recorded an uneventful night.  The next day, Cilley investigated the location where the grounding had occurred:

About 4 a.m. yesterday [November 6] placed a shot-plug buoy in 3 fathoms of water as near the elbow you directed my attention to as possible.  Sent two boats in the morning to examine and find the exact spot we touched; were unable to find less than 14 feet of water.  I think we grounded on some old wreck and it was so warm-eaten that we crushed it level with the bottom. The small buoy remains there.

I would point out the buoy planted in the early morning of November 6 was not at the site of the grounding, but rather part of a system of channel marking undertaken by the Federals at this time.   Sounding and marking the channel was a important undertaking, given the designs to force passage.  The monitors drew between 10 and 12 feet.  Defining the limits of the channel was a prerequisite to such action.

Commander Andrew Bryson reported the particulars of Lehigh‘s grounding on the night of November 15-16 in his report:

I anchored the ship in 3¼ fathoms of water, on a half-ebb tide, feeling that she was perfectly secure.  On the making of the flood tide she swung, and, in swinging, it is my belief that she touched on a lump, and there hung.  The water was so smooth, and she went on so easily, that it is impossible for me to say at what time during the night she touched.  After daylight I made the attempt to get under steam, and found to my surprise that the ship was on the bottom.

Bryson’s sounding of 3¼ fathoms indicates about 19 to 20 feet of water where he anchored.  The “lump” he reported could have been a sandbar pushed up by the current.  Or it could have been a previously uncharted shoal.  The last proper surveys of the channel were conducted years before, prior to the start of hostilities.  And no channel maintenance could clear those natural obstructions until the combatants ceased firing.

Charleston’s tricky tides and ever changing channels coupled with the man-made obstructions to offer the US Navy a difficult problem for even experienced ship captains.  Indeed, in order to get to those Confederate obstructions, Rear-Admiral John Dahlgren needed a clearly marked and measured channel for his ironclads to operate.

(Citations from ORN, Series I, Volume 15, pages 82-3, 119.)

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