Acoustic Shadows: SYW Scenario and Game

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Acoustic Shadows

(or guns with the Wind)

Or… March to the sound of the guns! But where is the actual fighting?

More often than not, nature adds to the fog of war. In this scenario, the main forces want to intervene to the initial fighting, but they are deceived by the direction of the sound of the guns. I caught the idea from a paper I read some 20 years ago, when I was creating ACW scenarios, but this can hold for any period. Acoustic shadows!

“The term acoustic shadow describes an event in which a person who would ordinarily hear a sound does not....

...These events also sometimes mean that those who should not hear the sound do hear it. The three most important causes of these abnormal situations are sound absorption, wind shear and temperature gradients”.

Map1

Acoustic shadows map w legends by Konstantinos Antoniadis, on Flickr

The Blue vanguard force 1, is foraging on Talberg. They have set their camp (A) for the night and a foraging party (half battalion strength) is returning from foraging from a nearby farm. Vineyards were ripe and they are coming back with grapes and other victuals found, but they are spotted the Red force 1 coming from the South, already deployed ad ready for battle. The Blue vanguard -having in mind to camp on Talberg hill for the night- have erected a hasty entrenchment for their artillery. Both forces take battle position and the guns start talking!

Behind Talberg hill, the main Blue force is entering from the NE. Simultaneously, the main Red force is entering from the SW (near Dichtewald woods). Normally, marching to the sound of the guns, the main Blue force would climb Talberg hill to reinforce their comrades, and, ignoring the presence of the main Red force coming, they might receive an attack on their left flank. But here the acoustic shadows intervene! What happens?

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Map2

Acousc shadows for wind by Konstantinos Antoniadis, on Flickr

The Talberg is a steep hill and the Dichtewald woods are thick. They create a sound barrier. At the same time, the strong NE wind blowing, carries most of the sound energy to fall on the Rocky Hill. The refraction of the sound, to the SE and NW, deceives both main forces! Both main forces hear the sound of the fighting as coming beyond Kleinendalsdorf village, so while the two vanguards clash on Talberg, the big fighting will occur in and around the village! Marching to the sound of the guns!

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The scenario is designed to be played with Honours of War rules, but can be easily adapted for other rulesets.

Orders of Battle

Blue force


1. Vanguard (on Talberg) Commander Dependable

1xLine Battalion
2xHalf Battalions, small
1xLight Infantry (hidden in Talwald)
1xLigt Artillery battery

Break Point: 2,5

Blue Main Force C-inC Dashing

2. Infantry Brigade Commander Dependable

1xGrenadiers, Superior
3xLine Infantry
1xField Artillery Battery

3. Independent

1xHussars

Break Point: 3


Red force

1. Vanguard Commander Dependable

3xLine Battalion
1xLine Battalion, Inferior
2xField Artillery batteries

Break Point: 3

Red Main Force C-in-C Dashing

2. Infantry Brigade Commander Dependable

1xGrenadiers, Superior
3xLine Infantry
1xField Artillery Battery

3. Independent

1xHussars

Break Point: 3

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Terrain

Talberg: Gentle hill, but the second level is steep (1/2 movement penalty)

Talwald: Open woods, soft cover, ½ movement penalty for non-light troops

Gun redoubt: Soft cover

Farm: Soft cover (can hold only half-battalion)

Fields west of the farm: Vineyards, rough going, ½ move penalty

Talbach : A brook, ½ move penalty to cross, banks provide an advantage for the defender

Marsh: Difficult ground, ½ move penalty

Dichtewald woods: Impassable

Kleinentalsdorf village: Rural, soft cover

Any unit on contact with the village houses: Difficult target (shot with -1)

Churchyard, graveyard (C) and some farm walls (D): soft cover

Rocky hill: Impassable, woods near rocky hill dense, hard cover, ½ move penalty

Area behind the rocky hill: Non playable, suitable to put your glass, measuring sticks and other paraphernalia
(so you can’t say I haven’t thought about the players’ comfort  )

Special rules

The Red Vanguard is the attacker, they move first.

Then the Main forces will throw a die to see who has the move initiative

According to the scenario, the Main forces move to the sound of the guns, so they are supposed to move to the direction of Kleinestaldorf village, ignoring where the vanguards are fighting. However, if they wish (and are able) to help their colleagues of the Vanguard, they may do so after they get in touch with the village, from where they have visual contact with the battle and realize where the sound of the guns comes from.

Red inferior battalion: Oh well, the fourth battalion of the Red Vanguard is lagging behind…It is the shame of the Red Army, bandits and rabble of all kinds, complaining they have not been paid and prone to desertion. In every round that the bring 1 or 2, they refuse to move. When they do so, The Red Vanguard commander needs to gt in contact with this battalion to exhort them to move forward. The only motivation to make them stop being reluctant, is to offer the loot the Blue camp on Talberg, so they will move only towards this direction.

The skirmishers of the Blue Vanguard are hiding in the Talwald woods. They cannot be attacked or shot before they reveal their presence by moving or shooting.

Blue Vanguard has two half battalions. Their commander may decide either to unite them on the first round, or let the leftmost half battalion to defend the farm.
In this case they cannot be united until the game ends.

Both vanguards have guns that must be manhandled. The Blue Vanguard has its teams and limbers at the camp and they need one round to bring them near their gun.
The Red vanguard commander was informed by the locals that there were some skirmishers in the vicinity, so he kept his teams at a safe distance (out of the map). He needs two rounds to bring them up and hinge his guns.

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Rounds: 10

Victory conditions:

Red Vanguard looting the Blue Camp: ½ VP. But if the Red inferior battalion touches the camp first, 1 VP.
At the end of the game:
Holding the farm: ½ VP
Holding the Cemetery or the Church: ½ VP each
Holding any bridge: ½ VP each
Every unit eliminated: 1VP, Half battalion eliminated, 1/2VP.
Minor victory: Break the enemy’s Vanguard and have more VPs at the end of the game
Major victory: Break the enemy’s Main Force
Total victory: Break the enemy!
Winning draw: No command is broken and you have at least two VP more.
All other results are considered a draw.

Optional:

If you like a more massive battle with some sort of congestion, allow on the third Round one more Infantry Brigade to follow the Main Force of each opponent, entering from their respective table edge, from the NW and SE roads: 1xGrenadiers, 3xLine Infantry, 1xField Artillery and then the Main Force breaks at 6.

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I would like to append the paper of the Acoustical Society of America I read 20 years ago, which inspired me to write this scenario

Acoustical Society of America
136th Meeting Lay Language Papers

________________________________________
Acoustic Shadows in the Civil War

 
Charles D. Ross cross@longwood.lwc.edu>

Department of Natural Sciences

Longwood College

Farmville, VA 23909

Contact during the meeting:

Monday evening and Wednesday afternoon

at the Norfolk Waterside Mariott Hotel (757-627-4200).

Popular version of paper 2aPAa1

Presented Tuesday morning, October 13, 1998

136th ASA Meeting, Norfolk, VA


On May 31, 1862, Confederate forces under General Joseph Johnston attempted an attack on Union forces to the east of Richmond. The ensuing battle, known as Seven Pines (or Fair Oaks), was one of Johnston’s rare offensive forays during the course of the war. More comfortable with the defensive, Johnston on this occasion concocted one of the most confusing, poorly executed tactical plans of the war.

Meant to synchronize forces on three converging attack routes, Confederate Major Generals James Longstreet, Benjamin Huger and D.H. Hill got their men tangled and then bickered over who had priority on the various routes. Even after this disastrous start, the Confederates still might have prevailed but for an unusual occurrence. Johnston planned to send reinforcements under Brigadier General W.H.C. Whiting on a flank attack whenever sounds of musketry were heard from Hill's troops, two miles southeast of Johnston's headquarters. The attack, if it had occurred in a timely fashion might have created a Confederate victory - but Johnston never heard the sounds of a battle which was raging in full force.

This is one of the earliest examples in the Civil War of one of a type of acoustical phenomenon that had been noted for two hundred years prior to Seven Pines and given the catchall name acoustic shadows. Though citizens of Richmond could clearly hear the battle five to ten miles to their east, the sounds of musket fire eluded Johnston's ears. Similar scenarios occurred at a number of other important Civil War battles, sometimes with dramatic effects on command decisions.

The term acoustic shadow describes an event in which a person who would ordinarily hear a sound does not. As mentioned below, these events also sometimes mean that those who should not hear the sound do hear it. The three most important causes of these abnormal situations are sound absorption, wind shear and temperature gradients. Sound absorption, as the name implies, occurs when material between the source and receiver of the sound waves absorbs all or part of the energy of the waves. Wind shear, in the context of this paper, describes a situation in which the winds aloft are considerably faster than the winds near the ground. The presence of wind shear can bend (or refract) sound waves downwards or upwards, depending on whether the wave is travelling upwind or downwind. Temperature gradients in the atmosphere can cause all sorts of refraction of sound waves. Especially interesting are those cases in which a temperature inversion exists: the temperature is greater at higher altitude than at lower altitudes. In this case waves are bent back down towards the ground.

When sound waves that would normally refract up in to the atmosphere are refracted back down towards the ground (either by wind shear or by a temperature inversion), they may reflect off the ground back into the air and be refracted again and again. This can create concentric zones of audibility and silence around an explosive sound. Sounds from the battle of Gettysburg that could not be heard 10 miles away were heard clearly in Pittsburgh, 150 miles away.

By examining war records, diaries and regimental histories, the causes of the various Civil War acoustic shadows can be examined. The battles noted for these abnormalities include Gettysburg, Seven Pines, Iuka, Fort Donelson, Five Forks, Perryville and Chancellorsville. The effects of these unusual acoustical events on the course of the war cannot be underestimated. Near dusk on May 31, 1862, General Johnston was severely wounded while reconnoitering near the front lines at Seven Pines. Johnstons mishap happened on land that would have been firmly in Confederate territory if Whiting's forces had been ordered to make their advance on time. By early the next afternoon, Confederate president Jefferson Davis had given control of the Army of Northern Virginia to the man who would lead it for the next three years - General Robert E. Lee.

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Umpire needed?

This is the problem of a tabletop general, he has God's view all over the field, so he may take decisions where real generals would not.
The presence of an umpire is always welcome. It is very good the players to be unaware of the scenario.

However, the Special rules are forbidding the players' Main forces to go towards the battleground of the Vanguards, they realize the situation only when they get in touch with the village, and then they will have a greater force of the enemy to face! So it will be a luxury if they dispatch forces to aid their comrades. Besides that, if they refrain from contesting the village, they will lose some Victory Points which my be proved crucial for the outcome.

Game with an umpire: A very interesting game may occur if the two Vanguard players play at a separate table, a mini reconstruction of the battlefield around Talberg hill.
Then, when the Main forces start clashing, they may be moved on the same table, keeping the relative positions of their units and the game goes on.

I thank Ken Marshall (from another forum) for the idea!

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THE GAME


I put the map again
Acoustic shadows map w legends by Konstantinos Antoniadis, on Flickr

Background. A massive rock. According to the scenario, this terrain feature is responsible for reflecting the sound of the guns of the battle that has already started between the detachment of the French troops attacking Talberg, defended by the British contingent.

AS (01) by Konstantinos Antoniadis, on Flickr

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The British on the Talberg heights

AS (03) Milt (01) by Konstantinos Antoniadis, on Flickr

The French in front of Talberg deployed for battle

AS (03) Milt (02) by Konstantinos Antoniadis, on Flickr

Miltiades played with the British-Hanoverian forces and I took the French

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The French, flags waving and drums beating, ascending Talberg

AS (03) Milt (03) by Konstantinos Antoniadis, on Flickr

...received by withering fire! The British are not joking! One French battalion mown down, another falling back to reform!

AS (03) Milt (06) by Konstantinos Antoniadis, on Flickr

AS (04) by Konstantinos Antoniadis, on Flickr

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The main French force, entering the narrow valley, marching towards Kleinentalsdorf village, sure that the sound of the guns is coming from the other end of the valley!

Far at the background, one can see the Hanoverian marching columns.

AS (02) by Konstantinos Antoniadis, on Flickr

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Returning to the other war theater. The French are shocked by the early loss of one of their battalions.

At the far right we see a French militia unit (in grey) which refused to move for two rounds and the French commander behind them, exorcising these rascals to march forward!

Miltiades finds the opportunity to send his skirmishers (partially shown-right) to harass them!

AS (05) by Konstantinos Antoniadis, on Flickr

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Next round, an aerial view of the situation.

The French attacking Talberg, while one of their battalions is still reforming, do nothing serious.

The French and Hanoverian marching columns have reached Kleinentalsdorf village and see each other!

According to the scenario, when they touch the first houses of the village, they will realize that there is also another battle taking place somewhere else.

French hussars cross the Talbach stream, followed by a French battalion and a battery.

AS (06) Milt (07) by Konstantinos Antoniadis, on Flickr

The Royal Nassau Hussars crossed the Talbach bridge, left of Kleinentalsdorf

AS (06) by Konstantinos Antoniadis, on Flickr

At the same time, the Hanoverian troops strive to find space to deploy at the other side of Talbach

AS (06)a Milt (08) by Konstantinos Antoniadis, on Flickr

Battalion Vastan, escorted by a battery, passing through Kleinentalsdorf

AS (07) Milt (09) by Konstantinos Antoniadis, on Flickr

AS (07) Milt (10) by Konstantinos Antoniadis, on Flickr

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Hanoverian Hussars deployed on Talberg. The French hussars deploy as well, to counter them.

AS (07) Milt (11) by Konstantinos Antoniadis, on Flickr

French and Hanoverian main forces try to take the best positions they can, facing each other at the banks of Talbach 

AS (07) Milt (12) by Konstantinos Antoniadis, on Flickr

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Miltiades dispatches one Hanoverian battalion to aid the British defending Talberg

The French attacking Talberg make a cautious advance

AS (08) Milt (13) by Konstantinos Antoniadis, on Flickr

AS (08) Milt (14) by Konstantinos Antoniadis, on Flickr

The French manage to link their forces

AS (08) Milt (16) by Konstantinos Antoniadis, on Flickr