The noble sentinel, in the hands of an experienced pilot, is quality piece of imperial equipment. It has many options, tactics, and uses that will be discussed and expounded on in this essay. Let us begin with some general information regarding the sentinel.
Firstly, and most obviously, it is a vehicle. This means that it is capable of being moved while the pilot is able to use the main gun. It also means that the sentinel is nearly immune to small arms fire. It has been noted that during any particular phase of a skirmish, a boltgun has about a one in eighteen chance of destroying a sentinel, assuming that the firer hits the sentinel. Plus, if the enemy takes the time to divert guns onto your sentinel, they are wasting a considerable ammount of firpower. Use this to your tactical advantage. Note as well, that the range of a sentinel's weaponry usually far exceeds small arms fire in the first place. As well, a sentinel will obscure friendly units behind the sentinel from view.
Secondly, the sentinel is a walker. This means that it moves across the battlefield at the same rate as infantry. As well, a sentinel is able to make an excellent close combat machine. Against normal infantry, the sentinel is able to make attacks without fear of injury. Even against tactical marines, the odds of serious damage to a sentinel is very small.
Thirdly, the sentinel is a heavy weapons platform. The sentinel is able to take most common heavy weapon available to the imperial guard. Thus, as far as firepower is concerned, it should be thought about in the same respect as a scaled down heavy weapon squad or another vehicle.
Furthermore, there are a few ways in which sentinel units stand apart from other units on the battlefield. Sentinels have a way of moving right before the battle begins so as to allow them to "redeploy" before a battle. As well, sentinels are always present on the battlefield. This is particularly useful when a battle suddenly follows in an "escalation" fashion where otherwise only infantry are present at the beginning of the skirmish.
The following is a list of the advantages of the sentinel:
With this knowledge, there are many different ways to use sentinels. Here are a few:
sentinels can be useful in tying up enemy units.
There are several different ways to use a sentinel in the assault role. The first is to use them to proactively engage enemy units. To do this, place the sentinel as close towards the enemy as you can, and use its free movement to advance even closer (preferably, but not necessarily behind cover). If this causes the sentinel to be destroyed, take comfort in that the vehicle absorbed weapons that were aimed at the rest of your army. In all likelihood, the units that an enemy brings that the sentinel is best able to engage is likely to move forwards. If it does, attempt to engage the enemy unit as quickly as possible. If the enemy retreats, then take advantage of the ground he yielded by moving your own units closer into the hole. As well, using sentinels in this fashion is more likely to break up the cohesiveness of a united enemy attack.
The second way is to reactively use sentinels to engage units. In this method, a sentinel will stay back near other friendly forces. In all likelihood, enemy units will attempt to engage your sentinels, but it is easy to present yourself as the most logical target for assault otherwise.
There are two types of units that a sentinel can engage in assault. The first is weak units. Sentinels can not, or are unlikely to, be destroyed by these kinds of units. While the sentinel is unlikely to kill a tremendous amount of the enemy, they will be able to hold up most infantry for an entire skirmish, effectively neutralizing them.
The second type of target is strong units. These units are likely to
destroy a sentinel in a single round of combat. While this is a less
optimal use of the sentinel, it can grant an enterprising commander an
advantage of time. If a strong unit were set to engage another vehicle,
for example, a sentinel would be able to force the enemy unit to engage
it for a turn while the other vehicle drove to safety. Also, it is
possible to draw a unit such as this for the purpose of leaving them
flat-footed and open to shooting the next turn. Finally, the sentinel
may be used in a conjoined assault with another unit in an attempt to
be a distraction, drawing enemy attacks towards it, rather than other
Note that this strategy should be used mainly as a distraction technique, and should be avoided as a primary mission for a sentinel.
As well, there is a technique known as the "sentinel bomb". Because sentinels are more vulnerable to explosion, a skilled commander can use this to his gain and run a sentinel against hard targets in the hopes that the sentinel will explode, due to an enemy attack, and take down enemy units in close proximity. This as well should not be used as a primary strategy, but rather when the opportunity presents itself. Note that an exploding sentinel can accidentally sentinel bomb your own units, so keep sentinels a bit away from the rest of your forces, or in obscurement of either terrain or smoke grenades.
In this form, a sentinel takes advantage of the fact that it blocks the enemy line of sight for units behind it.
The first use of this tactics is in conjunction with your other vehicles. In this way, a sentinel should be deployed in front of a vehicle (or to the side, and then use the free movement at the beginning to step in front), or should be deployed in front, and then use the free move to move forwards, if the other vehicles themselves will be advancing. Good use of this in conjunction with terrain or other sentinels will either totally block the vehicles in the back from enemy sight, or it will count them as obscured targets. Note that clever placement can also allow stationary units to shoot at enemy units while remaining "hull down".
As well, note that any enemy unit that wishes to shoot at your anterior vehicles will need to pass a test of leadership, or they will be unable to resist shooting at the sentinel. In any case, your enemy is much more likely to try and shoot at the sentinel, whether the units could shoot past them or not. Note that this can be highly exacerbated by giving sentinels smoke grenades as this will make them larger targets than other vehicles, as well as making them more likely to survive enemy anti-tank firepower.
The second use of the screener tactic is with infantry. This works on the same principle as the former, requiring enemy units to take leadership tests, as well as being the most prominent and obvious target for an enemy commander to shoot anyways. Note that this tactic is easier to combine with other, more stationary tactics. As well, note that the sentinel must be kept farther away from infantry than vehicles, as the sentinel has a distinct chance of exploding due to enemy fire.
Another use of the sentinel is that of the harasser. This comes in three forms.
The first form is to remain with your gunline and attack enemies from long distances (acting as a "sniper"). This is advantageous to sentinels with long range cannons. As well, it is easily combinable with screening of infantry and vehicles that do not venture out to assault. It is also useful for engaging onrushing enemy assaulters in a pinch.
The second form is to advance with vehicles. This is advantageous to any assault, as sentinels in this role will continue to block line of sight and serve as a distraction while being able to engage enemy counter-assaulters and being able to fire their weapons. This is especially important if the sentinel is equipped with short ranged weapons. As well, sentinels used in this fashion are more likely to attack enemy side armor, and are more likely to disrupt enemy actions (as you can assault units while your tanks roam free of gunfire threat, or your enemy will need to retreat to avoid assault).
The third form is to assault by themselves. This includes either dropping them in, or running forwards without the help of other units. This presents several different tactical options. Firstly, it allows sentinels to much more easily attack side and rear armor, especially when deepstriking. As well, sentinels used in this fashion provide an excellent distraction. Few enemy commanders are able to resist charging vehicles, especially when there are several of them. This tactic can buy you turns of relative peace on your gunline, as well as putting the enemy in a generally static position.
It should also be noted that it is possible to draw an enemy away from their main force in deployment, as many commanders will feel that it is important to address the threat that a unit on an otherwise refused flank presents.
Finally, we come to a quick survey concerning the equipment of a sentinel. First, their possible armaments should be discussed.
The heavy flamer: This option is good for many reasons. Firstly, it is very inexpensive. If you wish to use a sentinel primarily as a distraction, assaulter, or a screener, this weapon is ideal. As well, in combination with the deepstrike option, allows you to get a relatively sturdy unit in with a deadly weapon quickly. This setup is limited, however, as this weapon renders the sentinel unable to commit harassing fire in any way. If you intend on using them as assaulters, this is an excellent option, especially when engaged in city fighting.
The multilaser: I do not condone the use of multilasers. The only advantage that a multilaser has is requiring you to get close to the enemy to use it, which is only an advantage in the assault role. This weapon's range precludes it from prime harassing fire (as it is less likely to be able to target weaker side and rear armor, unless dropped in), but, unlike the flamer, it fails to excel in the assault role. While this sentinel pattern is still useful as a distraction, it is more expensive.
The autocannon: This weapon is excellent at harassing fire. A sentinel equipped in this fashion is set to engage enemy light infantry or vehicles until the sentinel can assault them (don't forget to assault lighter vehicles with sentinels! A pair of medium-strength attacks is, in the least, a surprise to enemy commanders (plus, you can continually assault and shoot heavy weapons over the course of the engagement)). The primary disadvantage to the autocannon sentinel is that it can not take on the heavier targets on the field, while the lighter targets are able to be dealt with with other weapons in one's army. Note, however, with it's extended range, the autocannon is much more likely to be able to attack "diagonally" across the battlefield, to attack weaker side armor of enemy vehicles. In general, this option is the best for commanders of limited available resources, or when the autocannon in specific is needed more in the army.
The lascannon: This is my weapon of choice for the sentinel. It allows the sentinel to handle any larger target with it's weapon, while being able to handle any smaller target in assault. This weapon has the principle advantage of being able to engage very hard targets (and, with its range, it is more able to shoot "diagonally" into the weaker side armor of enemy vehicles on the other side of the field). This means that it is very easy for a sentinel to recoup for its cost in enemy casualties As well, this greatly increases the threat level of this vehicle making it the perfect screener, while keeping it an excellent harasser.
Now, let us continue to the other upgrades.
Hardened fighters: This upgrade is useful if you wish to assault with the sentinel. It is, however, limited mostly to fighting where the extra attack might get an extra wound that allows you to win an otherwise tied combat, or prevent the sentinel by being otherwise overrun (or enemies that you intend to actually destroy in close combat, as unlikely as that is). In all likelihood, you will get the desired results without this somewhat expensive upgrade.
Drop troops: This can be used for either assault, or harassment. In assault, it lets you land a heavy flamer next to enemy formations (if it scatters properly), or target the side armor of vehicles. The one major disadvantage is the distance which the sentinel may be off from it's intended target (sometimes hitting front armor, or, worse, deepstriking in a way where the vehicle is destroyed). Deepstriking also damages harassment somewhat in that deepstriking sentinels are not likely to appear until the battle has already advanced to some degree, wasting valuable shots. In any case, the sentinel will provide a grave distraction to enemy commanders, who must now realign heavy tanks to avoid side armor damage, as well as realign infantry and light vehicles to avoid assault. The enemy will as well certainly pour much firepower at the sentinel, allowing the rest of your forces relatively free movement.
Smoke grenades: This is a useful upgrade for tanks that will fulfill the screener role. This upgrade allows the sentinel to remain at the same threat level (though not able to use it's weapon, it is now a far more conspicuous target), while increasing it's survivability, thus allowing more fire to be drawn away from other targets.
Extra armor: This is only useful to sentinels that are to be used as screeners. In any case, it provides only limited protection, while it's effects, when triggered, do not gain a substantial increase. In effect, this upgrades a sentinel to be able to run and hide if it is stunned. This gives little advantage, as hiding prevents a sentinel from completing any assault, harassing or screening moves or attacks. Indeed, it would be better to have the sentinel sit out in the open so as to distract the enemy to launch a second volley of gunfire at the sentinel, while key other elements in your force move unscathed. Use this to your tactical advantage. As well, note that, being an "opened top" vehicle, the vehicle has a poor chance of ever being stunned in the first place. The only particularly redeeming feature of this upgrade is its price.
Armored crew compartment: This upgrade has very limited use, and its cost makes the upgrade undesirable. For the slight ability to survive more, and the loss of some ability to "sentinel bomb", the upgrade costs half as much as another sentinel, which will invariably do more.
The following are a few mistakes that less experienced commanders are apt to make.
"The sentinel is fragile" This is simply untrue. Note that an AV10 armor rating is immune or nearly immune to all infantry small arms. A tactical marine has a 4% chance to take down a sentinel per shot. This means that it takes 13.5 marines a turn of rapid firing straight into the sentinel to bring it down. This, of course, is an abhorrent waste of firepower, and gives you many tactical advantages, as discussed before.
Against heavy weapons, sentinels, being vehicles, quite naturally have less survivability. Armed with a heavy bolter, a tactical marine has a 22% chance to destroy the vehicle. Note that it takes several heavy bolters to reliably down the vehicle, and in any case, draws heavy bolter fire away from infantry, or the AV10 sides or rears of other vehicles. Note as well that the autocannon and lascannon have a far greater range, and thus should never be subject to heavy bolter fire, while a heavy flamer armed sentinel should be in close combat after a turn.
Against more powerful heavy weapons, the sentinel obviously is in a harder place. Note, though, that these are the kinds of weapons that should be shooting at your heavier tanks. This means that if a sentinel is acting as a screener, it doesn't matter if it is blown up early on, as it has given your other vehicles the chance to rapidly advance on the enemy, and the sentinel's job is complete. Likewise, though it ends the sentinel's job as a harasser, it does still serve the same distraction as above.
"The sentinel is slow" While this vehicle is, in fact, more slow moving than it's treaded counterparts, remember that the reach of a sentinel's guns (or its alternate means of delivery) negate this problem for every weapon but the multilaser. Remember as well that sentinels, even if they must walk, are likely to get to the other end of the battlefield in time to be useful. As well, note that sentinels don't suffer the same debilitating effects of tracked vehicles when moving through difficult terrain.
This has been a brief overview of the sentinels including their equipment and roles on the battlefield. In conclusion, don't be afraid of assault, don't be afraid of sticking them out in front, and always remember to use the "free macharian cross" that they have, as well as being always able to deploy, even in the worst circumstances.