Rolling Barrages in FWW

[Der Landser]

I am trying to correlate the information given in the Rolling Barrage dialogue to the distance the Barrage will advance each turn in order to keep my troops safely behind the advancing Barrage. The example below is from the Getting Started scenario.

Allied Powers, From: 06:05 26/9/1918 to 06:30 26/9/1918, Start Line: (0,10) - (8,10), End Line: (0,1) - (8,1): 3x3: 155mm Howitzer
Allied Powers, From: 06:05 26/9/1918 to 06:30 26/9/1918, Start Line: (8,12) - (15,12), End Line: (8,1) - (10,1): 3x3: 155mm Howitzer
Allied Powers, From: 06:05 26/9/1918 to 06:30 26/9/1918, Start Line: (15,12) - (22,12), End Line: (15,1) - (22,1): 3x3: 155mm Howitzer
Allied Powers, From: 06:05 26/9/1918 to 06:30 26/9/1918, Start Line: (22,11) - (30,11), End Line: (22,1) - (30,1): 3x3: 155mm Howitzer

So, this Rolling Barrage starts at 0605 and ends 6 turns later at 0630. The Barrage advances a total of either 10 or 12 hexes during that time. I assume that the Barrage that advances 12 hexes would advance at a rate of 2 hexes per turn. What happens in the case of the Barrage that advances 10 hexes, does it pause at some point for 2 turns?

Essentially, I would like to know how to accurately predict how a Rolling Barrage will advance by analyzing the data in the Rolling Barrage dialogue.

[Compass Rose]

Great question. I too, would like to know.

[Volcano Man]

I will try to help.

Just taking one of your lines in the example...

Allied Powers, From: 06:05 26/9/1918 to 06:30 26/9/1918, Start Line: (0,10) - (8,10), End Line: (0,1) - (8,1): 3x3: 155mm Howitzer

Let's break it down piece by piece:

.....Allied Powers, From: 06:05 26/9/1918 to 06:30 26/9/1918

This is obvious I am sure. For the Allied Powers side, the barrage will occur from the time and date, to the second listed time and date where it will cease.

.....Start Line: (0,10) - (8,10)

This means that the start point of the barrage will be at hex 0,10 and the line will proceed to 8,10. In other words, the barrage will be along a line between those two points starting at 06:05 26/9/1918.

.....End Line: (0,1) - (8,1)

Similar to the start line, these are the two points that denote a line that the barrage will be on when the barrage ends on the end time mentioned above. In other words, the fire will be along a line between those two points at 06:30 26/9/1918.

.....3x3: 155mm Howitzer

This means that the barrage will be conducted by 155mm Howitzers, with 3 shots and 3 three sets of shots. You do not know the actual number of guns per barrage however, but typically these are grouped in batteries (so in this example it is probably 4 guns). So, a battery of guns firing three times, and in three groups of shots.

To put it another way, each time the artillery impacts, it would have X number of shots, and Y number of sets of shots. In this example X = 3 and Y = 3. The aim point is determined by Y sets of shots and X shots will scatter around that aim point. So, three times the game will determine the aim point along the barrage line and drop three shots. Each time it does this then a new aim point will be determined between those two points and three more shots will fall (for a total of 9 impacts).

Now the detail is what happens between the start and end point. What FWW does is, it takes the start and end line, and the start and end time, and it spreads the fire between the two so that it will walk between those two points. If the start and end time is a very long interval of turns and the start and end points are moderately spaced apart, then the barrages will move very slowly. If the stand and end points are very far apart and the length of the barrage is very short then it will move quickly, too quickly, between the two points.

In most cases (like your example) the barrage is broken into a battery firing a small parts of the same barrage line. However, in some other cases you have to pay attention because a barrage may move forward horizontally then stop, and then it may resume vertically, parallel to your advance walking outwards. Or it may shift to a specific point of interest and bombard that for a bit before resuming. You can get quite detailed with the rolling barrage in the scenario, as was historically the case of course.

One thing to watch out for is that you always have a chance a round may fall off target ... nothing you can really do about that other than don't bunch up too much as you follow it. No doubt in most cases the barrage will get to the enemy front line and proceed beyond it and leave you behind while you are still dealing with the enemy too, it happened frequently (historically speaking).

I hope that helps.

[Der Landser]

Thanks for the in depth explanation VM. I'm clear on most of your points, but I still have a few questions regarding how the Barrage advances.

Now the detail is what happens between the start and end point. What FWW does is, it takes the start and end line, and the start and end time, and it spreads the fire between the two so that it will walk between those two points. If the start and end time is a very long interval of turns and the start and end points are moderately spaced apart, then the barrages will move very slowly. If the stand and end points are very far apart and the length of the barrage is very short then it will move quickly, too quickly, between the two points.

So, does this mean that the Barrage will advance in equal increments of distance during the allotted time?

In the second line of my example above, the Barrage has a duration of 6 turns and it moves a total distance of 12 hexes during that time period. I deduce from your explanation that the Barrage will move forward 2 hexes each turn until the end time and end line are reached.

The first line of my example is problematic, in that the Barrage only moves a total distance of 10 hexes during the same time period. How will the game engine handle this situation? Will it linger at the start line for 2 turns and then move forward at a rate of 2 hexes per turn, will it stall during one of the intermediate turns for 2 turns and then continue forward, or will it progress forward at 2 hexes per turn and then linger at the end line for 2 turns?

[Volcano Man]

In the second line of my example above, the Barrage has a duration of 6 turns and it moves a total distance of 12 hexes during that time period. I deduce from your explanation that the Barrage will move forward 2 hexes each turn until the end time and end line are reached.

Correct.

The first line of my example is problematic, in that the Barrage only moves a total distance of 10 hexes during the same time period. How will the game engine handle this situation? Will it linger at the start line for 2 turns and then move forward at a rate of 2 hexes per turn, will it stall during one of the intermediate turns for 2 turns and then continue forward, or will it progress forward at 2 hexes per turn and then linger at the end line for 2 turns?

Well, in that case it will round off. So, in the eample, what you end up with is 1.67 hexes per turn, so essentially in some turns it may move forward one hex and in another turn it might move up two hexes (depending on the decimal). Specifically, in the example, it will move forward two hexes in turn 1, then one more hex in turn 2 (3.33 total), then two more hexes in turn 3 (5.01), then two hexes in turn 4 (6.68), and then one hex in turn 5 (8.35), and finally two hexes in turn 6 for the total of 10 hexes. I could have made a mistake with the math but hopefully you get the idea.

[Der Landser]

Thanks for clarifying the Barrage advancement mechanics VM. So the take away here is to be careful how closely your troops follow the Barrage and to expect slight deviations in the rate of advance in addition to accounting for the inherent indirect fire scatter effect. Thanks again for your time and effort explaning this.

[Compass Rose]