On July 16, 1864, Brigadier-General Henry Hunt offered a report to the Army of the Potomac’s headquarters in regard to siege preparations. The report was somewhat inverse of what one might expect. Rather than focused on what was being done, Hunt responded to an inquiry as to how quickly the siege preparations might be undone (and materials withdrawn) if the Confederates abandon the lines or the Federals opt to abandon the siege for other reasons. Sort of the staff work that a good commander (in this case Major-General George Meade) presses. While the conclusions reached by Hunt are of little use to us today, as not supporting “what if” scenarios of interest, the particulars he offered are worth consideration. They speak to the magnitude of the effort required to lay siege at Petersburg:
In compliance with the direction of the general commanding to furnish a report as to the time which would probably be required to Withdraw the siege train and material in case it should be desirable, I have to state that the siege material which will be brought into requisition if operations are fully entered upon will be: Forty siege guns, for which must be kept on hand in the magazines for daily supply, 6,000 rounds of ammunition; for 6,000 rounds 100 wagons are required; for 30 mantlets 10 wagons; 40 platforms 40 wagons; implements, equipage, &c., 10 wagons; 20 8-inch mortars 20 wagons; 3,000 rounds of ammunition 60 wagons; implements and equipage 20 wagons; 20 10-inch mortars, &c., 100 wagons: 20 Coehorn mortars and ammunition 30 wagons; total, 410 wagons. Twenty more 8-inch mortars are expected for the siege train, and if received will be used. To move them there will be required another 100 wagons.
To move and maintain the siege batteries – 40 guns, 20 10-inch mortars, 40 8-inch mortars (20 on hand at the time, with 20 more expected), and 20 Coehorns – required 510 wagons. With the number of guns, platforms, rounds of ammunition, and wagons in mind, Hunt calculated the time needed to withdraw the siege weapons… in a round about way:
The loading of the material in order to withdraw it must be done by night, and probably even then under fire. The movement of so many wagons can scarcely be made and the noise of loading heavy bodies finished without being heard by the enemy when the lines are so near, as in this case; nor will it do to sacrifice any portion of the material if there is any prospect of its being needed within a month. But little over half the supply of ammunition estimated for has yet been received, although it is sent forward as rapidly as it can be procured. The time needed to load the wagons will be necessarily much longer than ordinarily required at depots. For instance, the positions of the batteries were not selected with any reference to convenience in this respect, and but few wagons can be brought up at a time or placed in favorable positions for loading, so that the number of men who can be employed at any given place will necessarily be limited. At many of the batteries the inconvenience and danger of providing the daily supply of ammunition will make a system of covered ways necessary for the men who transport it from wagons stationed so far in the rear as to find cover from the enemy’s fire, and also from the approach of the wagons to these points. Time, therefore, becomes the most important element; forty-eight hours would, therefore, be necessary, under favorable circumstances, to remove the material.
And did he get to the point?….. Yes.
I do not think it probable that the entire train could be withdrawn in less than three days.
Hunt went on to say the guns and platforms would be moved last, as to at least give the impression the siege was continuing. With that, Hunt warned, just in case there were any schemes floating about which pointed in directions other than a prolonged siege:
For these reasons the planting of the batteries should not be commenced until it is determined to carry through the siege operations, or, as an alternative, in case a sudden movement of the army should be deemed advisable, we are prepared to sacrifice a large portion of our material.
Meade forwarded this report to Lieutenant-General U.S. Grant, prefaced with a status report of the siege preparations:
In compliance with your wishes, preparations have been continued for commencing the siege. Batteries are being erected for placing guns and mortars in position to silence the enemy’s fire at the salient on the Jerusalem plank road. The chief engineer estimates that it will take eight days to finish these works and have them ready for their armament. The chief of artillery will require three days to unload the vessels now containing the siege guns, mortars, and materials.
Meade added, for emphasis, a summary of Hunt’s conclusions:
In case of withdrawal, besides the three days indicated in his report for withdrawing these guns, if reloaded at the landing where the vessels now are, Broadway Landing, it would require three additional days, but if they are carried to City Point and there reshipped, this last estimate would not enter into the calculation. I have deemed it proper to lay these facts before you, as they may be material to you in your future plans, and to say that I have directed the siege works to go on and in the course of three or four days shall commence the unloading of the guns and material.
Just some figures to have handy… so to speak. Six days to break-up the siege and move the materials – at great effort. Sort of means both feet were solidly in the ring by mid-July 1864.
The mine will be ready in a day or two, but will not be loaded or sprung till the effect of our operations against the salient is ascertained.
Digging a shaft under the Confederate position was one thing. Getting all the pieces in place to take advantage of the planned mine blast… well that was another. More long days of work were required.
(Citations from OR, Series I, Volume 40, Part II, pages 276-7.)