Visualized in Combat Mission: Berm Drills

 A Tactical Vignette

Introduction

The berm drill is a small unit standard operating procedure (SOP) conducted by vehicles engaged in direct fire combat, also known as a battle drill. It involves a vehicle or vehicles moving from a hide position to a hull down position, engaging any targets present, and then moving back into a hide position to reload or displace. It is a simple yet critical technique that both enhances lethality and survivability.

The purpose of this writeup is to give the reader a strong idea of what the hull down position is, what a berm drill is, why they are useful and how to do them in Combat Mission. Bil has a great post giving an overview of what hull down is and how it can be applied in Combat Mission. I highly recommend checking it out, as it is much shorter than this writeup if you are looking for a quick guide.  

What is Hull Down?

The definition, taken straight from Wikipedia: “In sailing and warfare, hull-down means that the upper part of a vessel or vehicle is visible, but the main, lower body (hull) is not.” Additionally, “ In modern armored warfare, hull-down is a position taken up by an armored fighting vehicle (AFV) so that its hull (the main part of the vehicle) is behind a crest or other raised ground, but its turret (or a superstructure or roof-mounted weapon) is exposed.”

To oversimplify, hull down simply means a vehicle has “taken cover” in the same way an infantryman would, while still being able to fire his weapon.

As shown, turret down means that both the turret and hull of the vehicle are completely behind cover. Only the vehicle crew can see over the obstructing terrain. Generally, this means that the vehicles main weapons cannot be used as they are also obstructed behind the terrain though there are some vehicles that have raised weapons, or weapons mounted on top of turrets that can engage from this position. The hide position means that the entire vehicle, its mounted crew, and all parts of the vehicle are fully obscured.

The benefits of hull down should be obvious, but I will enumerate some of the benefits anyways. To help explain the benefits of hull down, I’ll use the infamous survivability onion to help illustrate:

This should be self-explanatory. In essence it illustrates all the things, both active and passive, you can do to prevent being killed. Not being on a battlefield is a pretty good way to ensure that you are not killed on a battlefield. If you must be on a battlefield, it is best not to be seen. If you are seen, it is best not to be shot at. If you are shot at, it is best not to be hit. If you are hit, it is best if the hit does not cause any damage to you. If the hit does cause damage to you, it is best if that damage is minor. You (hopefully) get the point.

In context to a hull down vehicle, we can see that all the layers of the survivability onion can be applied. First off, if possible, you should avoid being in places that are obvious. If there is a single terrain feature that provides a hull down position, it is safe to assume that the position is as obvious to the enemy as it is to you. By being in places the enemy does not expect you, you avoid “being there,” in this case there being a good artillery target. Additionally, limiting your exposure also helps you not be there. Frequently reversing out of hull down and into a hide, especially when reloading, further reduces your exposure and frustrates the enemy’s attempts to acquire, target, and hit you. Being hull down makes it harder for your vehicle to be spotted. In hull down the vehicle is both presenting a smaller target (harder to see/hit) and breaking up its contour (the normal shape of the vehicle). A green tank turret along a berm with bushes might just look like a bush at a glance from a distance. If the onion fails you to this point and your vehicle is engaged, you are still harder to hit because you are presenting a smaller target. Note: modern weapons are quite literally laser accurate. Main gun rounds from tank cannons are extremely accurate and fly too fast to react to. Missiles can either be guided to an area target smaller than the turret of your vehicle or have a top-down attack feature that negates hull down advantages. Therefore, in modern warfare the upper layers of the onion (don’t be there, don’t be seen, don’t be engaged) are even more important. A larger target that is fully exposed tends to be easier to hit.

It is only when all of these layers of the onion fail (or more appropriately, you fail the onion) that things like tank armor, penetration capabilities, and survivability come into play. Another way of thinking of the survivability onion is that all of those layers add additional armor to your vehicle. And yes, I’m going to make the obvious reference here:

“Ogres are like onions. Onions have layers, ogres have layers.” – Shrek.

Be like Shrek, have layers. The more I think about that scene, the more parallels I can think of regarding the discussions had around hull down vehicles and Combat Mission…

Hull Down in Combat Mission

There are two ways to place a vehicle into hull down in Combat Mission. There is the manual way, a tried-and-true procedure outlined in Bil’s blog post referenced above. Then there is the “Hull Down” command under Movement Orders, which is simple and effective but requires a bit of explanation that can be confusing to some.

1. Manual Hull Down
Taken straight from the master himself:
Procedure:

• Add your movement waypoints up to the hill/ridge you want to deploy on
• Select the last waypoint and, using the targeting command, check to see if you can "see" into the target area (area where you suspect or know the enemy is located), if you cannot see into the targeted area, then move the waypoint until you can
• When checking LOS with the target command it will say either "Spotter is hull down" or "Spotter is partially hull down".. either is acceptable.. if it does not say this move the waypoint until it does
• In the following image, the player desires to have the tank masked from enemy observation on the left, while it is hull down to enemy units on the right

Bil also included a very helpful CM illustration as well:

Manually placing your vehicles in hull down is perfectly viable. It is expedient for times where you just need to eyeball an approximate hull down position for a vehicle or vehicles. Many players (Bil included) default to this method as it is both effective and stands the test of time. 

2. Hull Down Command

The Hull Down Command was added to Combat Mission in Engine Upgrade 4. Here is a step by step on how to use it from the Combat Mission Engine Manual:

• This command allows a vehicle to move forward until only the turret is exposed to a specified target, and then the vehicle stops moving. Here is how to conduct a Hull Down command:
• 1. Select a vehicle and give it a Hull Down Movement Command. This is the furthest point that the vehicle will move forward to if it doesn't establish Hull Down for any reason.
• 2. Optionally assign a Target Command to the point that you wish the vehicle to become Hull Down to. This target can be either a point on the ground or an enemy unit.
• 3. If you don't assign a Target Command, then your vehicle will attempt to become hull-down to the waypoint location you set in step 1.
• 4. The vehicle will follow the Hull Down Movement Command and move forward. When the vehicle is Hull Down to the designated target (or waypoint if there is no target), the Hull Down command will be automatically canceled and the vehicle will stop moving.
• 5. If the designated target is an Area Target, the vehicle will cancel the Target command upon reaching Hull Down. If the target is an enemy unit, the vehicle will begin attacking the target once it reaches Hull Down.

Some people have trouble following this and correctly implementing it in the game, so I will attempt to illustrate it with screenshots.

Here we have a tank in a hide position, and we want it to move up to the top of the rise so that it is hull down in relation to the 2^nd floor of the 2 story structure.

Follow Step 1 from the manual and select the tank and give it a Hull Down Command:

The Hull Down Command waypoint should be placed at the top of the terrain rise.

Select the Hull Down Command Waypoint (with the tank selected, either click on the red line, or the white node at the end of the red line) and then click the Target Command. This will draw a target line from the end of the Hull Down Command Waypoint (the white node) to wherever you point the mouse. To make the tank go hull down in relation to the 2^nd story of the building, simply click the target command on the 2^nd story of the building.

This tells the tank to move up the slope until it is in a hull down position in relation to the target, which in this case is the 2^nd story of the target building. Note: you can target buildings, pieces of terrain, individual vehicles, etc.

The turn is processed and…

The tank is in a perfect hull down to the 2^nd story of the target building, just like we wanted. This is confirmed by the text displayed under the target line when the Target Command is selected and moused over the target building. It displays, “Spotter is Hull Down.”

It’s that simple.

Berm Drill

A berm drill is the name given to a SOP/battle drill for armored vehicles to perform. It involves the vehicle moving from a hide position to a hull down position, engaging the enemy, and then reversing back into the hide position to reload. It is easily seen here:

Here is another video showing a tank conducting a berm drill, but from the perspective of the Tank Commander (TC). Skip to around 4:48 in the video to see it:

The utility of such a drill should be obvious. A ready comparison is an infantryman popping up to fire and then ducking back into cover. It allows you to engage the enemy without prolonged exposure to enemy return fire, while also frustrating enemy attempts at targeting and engaging you.

The Berm Drill can be employed in Combat Mission in a number of ways. I will show off one technique, but there are other order combinations to achieve the same or similar effect. This post also does not go into detail such as the importance of displacing to alternate firing positions and battle positions, but those are important elements of the Berm Drill as well.

The method I will show off here involves giving the tank a Move Command with a 10 second pause, then a Reverse Command with a 10 second pause, then another Move Command with a 10 second pause, and finally a reverse command. This tells the tank to move up, sit still for 10 seconds (the tank will engage anything it can spot) and reverse. It will repeat this process once more before coming back to rest in a turret down position. My tanks are in dugouts to provide them with hull down positions. Remember, you can always check to see if the tanks are hull down at the end of the Move Command by selecting it and using the Target Command. If the text “Spotter is Partial/Hull Down” then your tank is hull down. A lot of this comes down to trial and error but sticking to the basics will go a long way.

A note on the amount of paused time. How much, or how little time is entirely up to you. I have gone with 10 seconds here because it allows the tanks enough time to acquire a target, lay the gun on, and fire before reversing. Others are more comfortable with 15 seconds or 20 seconds. A lot of the timing comes down to the equipment you have (an M1A2 Abrams has much better fire control—meaning faster acquisition and shoot times—than a T-55) and the capabilities of the enemy you are up against. For example, if you are up against an opponent equipped with Javelins, you want to minimize your exposure time as much as possible. Slow firing and moving ATGMs will give you more breathing room while in hull down before you must reverse into cover.

A note on the Hunt Command. A unit that spots an enemy while in the middle of executing a Hunt Command will not honor a pause command on the Hunt end waypoint. For that reason, I prefer using Move or Slow Commands to move my armored vehicles into hull down position.

Finally, a disclaimer. Unfortunately, Combat Mission is a game that is very lacking in Quality of Life features. It requires a lot of clicking and waypoint finicking to get even a single platoon to execute a Berm Drill for one turn. It is a lot of work, and it is tedious (which in many cases is CM in a nutshell). Domfluff is fond of saying that, “Patience is the final boss in Combat Mission.” I completely agree with him.

With out further ado, this is just a minute of Berm Drill on display:

As you can see a number of enemy tanks are successfully engaged and destroyed while no friendly tanks are hit, or even engaged. The enemy has a hard time identifying my tanks and as a result cannot shoot back before my tanks are safely in cover again. Rinse and repeat this process, and you can start to see how a platoon of tanks can wipe out a company or larger formation by itself. Remember, this battle drill can be scaled. It is entirely possible to have an entire company, or even battalion all performing a Berm Drill in a defense.

As mentioned, this is a topic with a lot of nuance to it. There is more than one way to skin a cat, as the saying goes. There is also further complexity involved as well. Displacing (moving to alternate positions) is usually necessary at some point during an engagement, whether it helps avoid accurate direct fire or the inevitable indirect artillery fire a competent opponent is likely be on you. This is well covered in another one of Bil’s blog posts, and I highly recommend giving it a read.

Hopefully this helps explain hull down, Berm Drill, its efficacy and how to do it.