"The Rebel Ram Arkansas: History of the Vessel, Her Construction and Strength"

georgew

First Sergeant
Joined
Oct 1, 2010
Location
southern california
The following article by Henry Bentley appeared in the Philadelphia Inquirer of July 25, 1862. Bentley apparently interviewed workmen and citizens of Memphis after the battle off that city in June of 1862. Of particular interest was his description of her engines and drive lines and provisions for protection of the propellers against drift in the river. Thank you to Jack Smith, who sent me the citation in October of 2009.
"Her Machinery: The engines of the Arkansas are low pressure and of about 900 horse power, all placed below the waterline and well protected from injury by hostile missiles. Her cylinders are said to be 24 inches in diameter and seven foot stroke. She is provided with two propellers, working in the stern and acting independently. These propellers are seven feet in diameter and are capable of making 90 revolutions per minute. In consequence of the independent action of the engines, one propeller can be revolved forward while the other is reversed, thus permitting the boat to be turned in little more than her own length. A network of iron rods an inch in diameter and with meshes more than a foot across, extends around the upper part of the propellers to project them from injury by floating logs and driftwood."
This description leads to several questions: the reported diameter of the cylinders seems small for a low pressure engine. These engines were reported elsewhere to be of the 'direct drive' type. It is possible that lower displacement cylinders could put out considerable power at high enough revs, but leaves the issue of just what "low pressure" is being assumed. We do know that her boiler and steam lines lacked a firebrick facing or felt covers for the lines resulting in engine room temperatures exceeding 130 def F in July and frequent exchanges of firemen and coal haulers. The structures to protect the propellers may have been the result of reports of multiple damage to the propellers of the Manassas when she was deployed upriver earlier in the war. The propellers themselves were reported to be sourced from New Orleans as well as the drive shafts. The engines were built and assembled locally in Memphis. They apparently required a very experienced engineer to keep them from stopping "top dead center" without warning. Chief Engineer George City was apparently up to the task, but his replacement, Ramsey, had no experience with this type of engine and had problems with them leading to a complete breakdown above Baton Rouge.
 
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