Mahan on Artillery Tactics, Part 4: More on the Defense

Let us continue the discussion of artillery as used on the defense, according to Mahan. And we again turn to Chapter II, verse 151…..

Those positions for batteries should be avoided from which the shot must pass over other troops, to attain the enemy. And those should be sought for from which a fire can be maintained until the enemy has approached even within good musket-range of them.

Outpost, 60-1.

Common sense at play here. Fuses are not fail-proof, no matter how good the quality control is at the arsenal. Short rounds were a concern then as they are today. A further concern was the ballistic path of the sabot used behind many projectiles. Though made of wood, that could still injure or kill. With the introduction of rifled guns, another concern entered play – the lead or soft iron sabots often sheered off after the projectile left the muzzle. Those fragments took less predictable paths.

The other part of this is the desired effect of allowing the cannon to engage right up to… and inside of… musket range. The “skirmisher” community will note that Mahan was writing this passage before the rifled-musket was in widespread use. However, we should note that well into the Civil War, 100 yards was still considered the effective range of those rifled-muskets, as the practitioners were focused on volley fire effects as opposed to the effective range of individual weapons.

Where the wings of a position are weak, batteries of the heaviest caliber should be placed to secure them.

Outpost, 61.

Another sensible suggestion here. But one that must play with earlier passages that dictated the bigger caliber pieces be placed on “the more retired points” as opposed to advanced positions. Looking back at the “taking away a course of action from the enemy” mindset, those batteries assigned to support the flanks would be there to remove an option to attack on a flank. Such implies, generally speaking, that in the defense the flanks should be tucked in or refused. I would not argue against that as a general application, but certainly not submit flanks should always be refused. Given terrain or other factors, one might extend a flank position to cover the front of the main defensive line…. you know… like in those simple entrenchments that Mahan wrote of in other volumes.

Thus far, Mahan has placed the light batteries (shall we say the “mounted” batteries?) and the heavy (or “foot”) batteries. What about the horse artillery?

A sufficient number of pieces – selecting for the object in view horse-artillery in preference to any other – should be held in reserve for a moment of need; to be thrown upon any point where the enemy’s progress threatens danger; or to be used in a covering the retreat.

Outpost, 61.

Stomp your feet here to ensure all the cavalrymen hear and heed this. Horse artillery, in the defensive, was not simply attached to the cavalry for support of the troopers doing what ever it is they do on the defensive. Instead, the horse artillery was a reserve force to be used when pressed. If we turn again to “taking away courses of action” then here we are considering how an enemy commander would follow up behind initial success. If that assault has indeed achieved a lodgement on the main defensive line, the next step would involve pressing reinforcements forward to enlarge gains and break the line. The counter, Mahan proposes here, is the rapid, flying batteries of horse artillery introduced to seal that fissure.

And if that cannot be attained, at least have those horse artillery batteries in position to dissuade the enemy from following up with a close pursuit. A handful of well placed shells from the horse artillery should at least cause pause.

Everything thus far we might summarize as “use common sense and good judgement.” But the next paragraph is where the armchair generals will set up and start typing comments….

The collection of a large number of pieces in a single battery, is a dangerous arrangement; particularly at the onset of an engagement. The exposure of so many guns together might present a strong inducement to the enemy to make an effort to carry the battery; a feat the more likely to succeed, as it is difficult either to withdraw the guns, or change their position promptly, after their fire is opened; and one which, if successful, might entail a fatal disaster on the assailed, from the loss of so many pieces at once.

Outpost, 61.

Yes, at first glance, Mahan is laying out an argument against massing artillery on the battlefield. And our latter-day Stonewall Jacksons are quick to point out massed artillery is often the key to victory!

The important part of this passage is “large number of pieces in a single battery.” This is a “battery” not as an organizational unit, but as a position. Reading as such, this is a warning about putting multiple batteries in one contiguous position. If those guns are not arrayed as discussed at earlier points in this discussion of artillery on defense, then such a collection would be a vulnerable, tempting target. Placing the guns hub to hub is not “massing the guns.” But arranging those guns, in accordance to the guides presented by Mahan, is.

What I’d contend is that Mahan was not arguing against what Henry Hunt would do at Malvern Hill. Just the opposite. Prior to July 1, 1862, Hunt organized and emplaced the artillery into a fine example of what Mahan encouraged through these couple of pages on defensive arrangements. Go through the checklist – good engagement ranges, cleared fields of fire, complementing postings, light batteries advanced, heavy batteries retired, wings protected, infantry kept clear of the guns, and all well supported. And that arrangement allowed Hunt to introduce fresh batteries and withdraw tired ones, with relative ease. Thus, what Hunt had at Malvern Hill was not a “large number of pieces in a single battery” but instead a massing of combat power on a good position which maximized the capabilities of the artillery. Famously, one year and two days later, Hunt will accomplish the same feat on another battlefield while defending Cemetery Ridge. We might easily turn to the other side of the war and point to good use of massed artillery at Fredericksburg.

I think what Mahan is arguing against in this passage is actually instances like Missionary Ridge. One might say the Confederate artillery positions on that ridge were well placed for a siege in which their fire would be focused on distant Federal lines. The problem was no proper adjustment was made when that position transformed, due to the shifting of tactical situations, to a defensive one. And so that checklist that Hunt met on those hot July days was not met on that autumn day outside Chattanooga – dead space under the guns even past musket range, no complementary postings, no advanced or retired positions, infantry lines interspersed with the artillery, and little room to move the batteries around. And if we circle back to the “taking away a course of action from the enemy” notion here, I’d posit this counter-intuitive thought with a wry smile: the position on Missionary Ridge was so bad that it invited Federal commanders to accept and pursue a direct assault as a course of action. And as a demonstration, at that!

The last paragraph in this section on defensive arrangements for artillery strikes to the logistics of keeping those guns feed:

In all defensive dispositions the ammunition should be most carefully husbanded. A fire should never be opened until the enemy is within good range; and, when once opened, be continued with perseverance and coolness up to the last moment in which it can be made effective.

Outpost, 61.

I’ve mentioned this a time or two before, expressed as “staying power” of the guns. By this I mean the time for which the gun can remain at a position and actively part of the battle before having to replenish ammunition. Obviously many factors come into play here. Not the least of which is the number of rounds in the ammunition chests (in other words, the smaller-bore weapons had more rounds to shoot, all things being equal… yet another reason to have those big guns at retired positions). As we alluded to above (and at other places on this blog), Hunt and other good artillery commanders mitigated this with a good system to rotate batteries in and out of the line. Hunt also devised a very healthy system to push full ammunition chests up to the points where needed. Such adds another requirement here to those “good position” checklists, in that we must also consider allocating space to allow all the traffic needed in order to maintain a position “up to the last moment.”

And I stress “staying power” over perhaps the cyclic rate of fire. More so than simple weight of metal, it was the paced, deliberate, and measured fire which was desired. So let’s cast off these notions that artillery was just there to belch out canister, send smoke into the air, and make a lot of noise. The impact of those big guns, particularly on the defense, was to shape the flow of the battle… taking away courses of action available to the enemy.

(Citations from Dennis Hart Mahan, An Elementary Treatise on Advanced-guard, Out-post, and Detachment Service of Troops, and the Manner of Posting and Handling Them in Presence of an Enemy, New York: John Wiley, 1861, pages 60-1.)

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