Defensive Formations: The Triangle Patrol Base


The Reinforced Triangle, or “RT” is one of the most effective defensive formations to use when setting up any base camp, whether conducting a security patrol, on the road during ‘GOOD’, or while in a semi-permanent base of operations being progressively developed in a protected or contested area. It is especially well-suited to progressive position development as described in Principles of Tactical Defense Parts III, IV & V,  and once expanded into what would be called a squad or platton sized perimiter, can easily be used as a ‘strong point defense.’

But long before that can happen, you and your team must be able to set up, position within, conceal all positions, provide security, and use the RT without violating any principle of use or criteria. That equates to many repetitions and hours of practice. Here’s the criteria for any perimeter formation:


  • An easily learned formation
  • 360 Degree Security/Observation
  • Interlocking fields of fire
  • Mutual Support between positions
  • Defense in Depth
  • Flexibility to expand or contract as necessary
  • Concealability

Granted, there are many ways to skin this cat, so to speak, but many other methods don’t lend themselves to Defense in Depth.  You can achieve Mutual Support and Interlocking Fields of Fire, but will need more than a four person NPT to achieve DID (Defense In Depth).  This isn’t a new formation, either.  Way back in the day this was my unit’s preferred ‘360’, and the one we recommend.  Why?  Simply it provides all of the above criteria and also fits well into any ‘play book’. It is ideal for use as a single, self-sustaining Patrol Base or “base camp”, and should the situation warrant, can be expanded into a series of RT’s that will provide an almost impenetrable perimeter as it grows and positions are improved into prepared, defensive positions, if the position is to later become a ‘Strong Point.’
As diagramed at the beginning of this post, the strengths of the RT become apparent:

  • Each position has the ability to mutually support all others by fire if required.
  • No one position is left without a fallback position, whether it is to the center of the RT or one of the remaining points and all positions can provide defensive in depth to any position under pressure.
  • 360 degree observation is achieved (positions are & mutual support).
  • Distance between positions is flexible (terrain & situation dependent)
  • Any position can be developed to hold/house 2 or more team members (each point of the triangle could be developed as a triangle in and of itself).


Moving In – The RT, like most other temporary perimeters, is established by “moving in” from a tactical movement formation by a fire team or larger group. For academic purposes, we’ll keep it at a four member team level and, again for academic purposes, we’ll presume we are moving at night, so we’ll use the file as our formation to move into and set up the RT.  (Note: That does not mean the only formation to use is the file; it just best suits night movement most of the time.  In terrain that’s open or sparsely covered, other formations may be be better suited; you’ll have to make that call.)

To move in, the FT Leader stops the team and signals what he wants done:

  • When each team member moves into his  respective positions
  • TL takes the center of the RT
  • TL check the positions; establish as appropriate tug lines, fall backs, emergency egress rally points, etc.
  • If and when to start improving the position (as warranted for the length of the stop – generally a 12 or more hour establishment would justify the establishment of at least hasty fighting positions).
  • Hygiene Considerations: All ‘cat hole’ areas should be downwind, down hill (if possible), 30 meters away from the RT, concealed, and not placed near any potable water source.

The team leader places the ‘points’ at the following clock positions by visual signals:

Point 1: 10 O’clock

Point 2: 2 O’clock

Point 3: 6 O’clock

12 O’clock while moving is always the direction of travel; the TL can use that or a landmark he and other team members can easily recognize, area of primary concern, or assigned area of responsibility when setting up the RT. It should be noted that RT doesn’t have a “front”; whatever is used to determine the 12 O’Clock direction is simply providing a baseline used for ease of RT establishment.  Defense in Depth is a constant of the RT; a threat from any direction will almost always be able to be engaged by at least 3 of the 4 positions.

Considersations for choosing where to place your RT:

  • When choosing position locations, pay attention to natural fire lanes, micro-terrain depressions that will help hide the occupant(s) without disruption of natural lines, and clear line of sight between positions if possible.
  • Walk in front of the selected position and view from an opponent’s perspective to find weaknesses.
  • If on a hilltop, remember to use the ‘military crest’ as your high point (the highest point on the hill that the entire slope can be covered by fire – typically about 1/4 to 1/3 of the distance from the actual crest to the bottom of the hill or ridge).
  • Never choose a position location that has ‘defiladed ground’ (cannot be covered by direct fire) in front of it.
  • If possible, employ natural barriers or channels that an enemy would have to surmount to attack your position.
  • The RT may not always be in a perfect triangle shape due micro-terrain considerations; make it fit tactical requirements, not the other way round.

Military Crest Illustration

Apologies for the poor visibility of the image.  Click on the image for a clear view.

Another aspect of the usefulness of the RT is its adaptability for applicants to change from a defensive position to a ‘jump off’ for an offense against an attacker.  With rehearsal of a specific play designed by the team leader to change from defense to offfense, the move, executed at the right time (when the attacker least expects it), could change possession of the intiative to the defenders and be the deciding factor on neutralizing the attack.

Bottom line:  The RT works!

18 thoughts on “Defensive Formations: The Triangle Patrol Base

  1. Pingback: DTG: Defensive Formations | Western Rifle Shooters Association

  2. Billy Dawes

    looks good on paper until people start moving. The TL has a line of fire in front of his own team members.

  3. Defensive Training Group Post author

    If the team has practiced together for just such an eventuality, such as moving out of the position while engaged, the inherent risk is minimized. If I’m understanding your comment corretly, having a line of fire in front of his own team members (as he’s the depth position) might be employed as a Final Protective Line (FPL).

    Like the piece says, there’s more than one way to skin this cat, so if it doesn’t seem viable, or your NPT doesn’t get a chance to train together much, by all means don’t use it. But that doesn’t negate the fact that this particular formation has been proven to be very effective.

    Thanks for stopping by!

  4. Wolverine

    I’m trying to visualize/ understand exactly what you meant by the switch from defensive to offensive. Am I following you correctly when I imagine one or two points remain engaged defensively while other(s) break formation to flank (or some other offensive maneuver)?

  5. Defensive Training Group Post author

    Yes, one or two positions could remain engaged while one or both maneuver to engage. Your IAD’s would need to be tuned to the scenario you imagine and then practiced until second nature.

  6. david

    Show me where this is accepted in military doctrine. It appears to be a neato new invention in someones imagination. Whoever drew that top diagram is either unable to effectively communicate visually or lacks a practical understanding of Fields of Fire. The illustration FOF are too close/broad. You are likely to shoot your buddies.
    And who is the lucky jerk in the center? If it is women and children, then great! Otherwise, you’re a pussy! Share the battle risk. Use the Wedge, Diamond or a Combat box. IMHO.

  7. Defensive Training Group Post author

    David – Look up ‘Defense In Depth.’ while you’re at it, ‘Mutual Support.’ And then, ‘inter-locking fields of fire.’ Then re-read the post. This is nothing more than a quick, effective way to provide DID, Mutual Support, and inter-locking fields of fire should it be necessary when setting up a patrol base or hasty defense. There is no ‘pussy’ in the middle. Again, READ the piece and check out the part about observation. Any time you’re in a small perimeter with just a 4 man team, your FOF are huge. The fact is that the RT works, it’s been used extensively ‘back in the day’ and is very adaptable to defending your team, family, or whatever. Don’t like the RT? Use whatever you want. It’s your choice. The RT is just another tool in the play book.

    Thanks for stopping by.

  8. david

    Fair enough. Will do. “Defense in depth” is a term that I am not highly familiar with… Will study that and respond to that.
    Are you say there is no one in the center of the formation? At a minimum, that diagram is awful. Thee concept may have some merit, but the FOF as illustrated are bad bad bad.
    If the center position is a combat position, this would be workable if center man is on a peak of a hill.
    My convention is this. There exists many good basic combat formations thatare already proven as simple and effective. This appears to be an overly complex departure from the basics that is light on benefit and heavy on risk and complicated. I work with small unit tactics (sut). Over the years, it is evident that volunteers struggle to master the basic fundamentals. Complicating the IAD (immediate action drills) or maneuvers will encourage failure.
    I will give it a second look though. Thanks in advance for the clarification regarding the man in the center.

  9. Defensive Training Group Post author

    The center position provides the ‘depth’ in Defense in Depth. Standard military doctrine of 2 positions forward, one back, and that doctrine goes way, way back. Sorry the diagram doesn’t tickle your fancy; one dimensional drawings do have their limitations when you’re not an artist, which none of us at DTG happen to be.

    It’s workable so long as the team leader does his job siting the positions, making sure fields of fire are marked in each position by sector stakes (not to be confused with aiming stakes, but sometimes are), and that his center position has appropriate observation for all three points of the RT. You should try this in the field sometime. And remember another factor: The terrain you set the RT up in determines the shape of the triangle. It’s most likely not going to be perfect like the drawing.

    It stands to reason that there are many good basic formations available. This is another tool. To be effective with any tool, you have to practice using it. If it’s not workable for your team, use whatever does work. Throwing out something that has, and does work with a well-trained team/group without careful evaluation of its merits doesn’t stand up.

    From your overall comments, it seems the drawing is what’s stuck in your craw. The RT is not an ‘immediate action drill’ (IAD); it falls under the umbrella of TTP’s (Tactics, Techniques, & Procedures). It is simply a way to site your people when stopped in a concealed position to allow for whatever needs to be done. It’s much, much better than just the ‘360’ circle with the leader and the comm guy in the center.

    Thanks for giving it a second look, who knows, you might find it’s a useful tool. Others have. If not, you’re no worse off than you were before you decided to look at it.

    Appreciate the feedback.

  10. david

    Okay, due dilligence done regarding DID. It dates back (reportedly) to the Roman Empire and runs through current military doctrine. So, point ceded… Thanks for the challenge.

    Like you said, different ways to skin the cat… It seems like this RT you put forward is a way of expressing DID. Much in the same way that “Peel” is a way to “Break Contact”, but not the one way to BC.

    You are right about the diagram being problematic (FOF too wide). But, I suppose any field supervisor worth his salt can translate that (as in, AIMING STAKES, limited FOF). So, that shouldn’t be a problem.

    Also, I am looking at this from the perspective of SUT (small unit tactics) and SUT would best utilize basic Combat Box, Wedge variation or Diamond. And, I frankly, cannot trust anyone that I have worked with to be firing from the center. However, at higher levels of operators, I can see how limited FOF from the center could be utilized, assuming the PL or gun in the middle knew where the others were situated. And assuming that they are not manuevering; of course.

    The lesson/value I can take from this is applying the tools of: expansion, decreasing size, shifting, flank maneuver, etc… can be applied to standard SUT formations. Generally, with SUT, the PL or Medic needs to be in the center and NOT SHOOT, per se. But as the formation enlarges, narrow shooting lanes can open up (terrain dependent). Also, higher levels of capability (read SKILL and COMPETENT DECISION MAKERS) can be trusted to know where the buddies are and only shoot in safe lanes. Other than that, I have found that everyone needs to carry his own water in a SUT formation.

    By definition of DID, the process introduces increased complexity and likelihood of failure (by it’s definition). So, DID or RT is not for the intermediate team. This is for higher level operators. I have the task of working with mostly Novice-Intermediate operators without any military training (SUT/Infantry etc). Further, the practical application of field maneuvers (basics) tends to lead to gross errors in judgement that gets the team killed in scenarios. I was projecting my years of experience training with civilians who lack trigger time. More experienced operators would not have this problem.

    Lesson: Civies and Preppers need to stick to the basics and master them. Higher level operators can delve deeper.

    Thanks for the challenge and intellectual exercise. You been bookmarked! I will revisit.

  11. david

    I am having a hard time finding any military history or reference to this particular formation. Could you help direct me to where u can read more about it? I don’t mean DID, mutual support or interlocking fields of fire… I mean the particular diagram-formation illustrated at the top. Who has used it and when? My team has expressed interest in discussing the merits on Saturday.
    I’m the guy who has to do the research.

  12. Defensive Training Group Post author

    The Air Force’s Air Base Ground Defense used it (and other formations such as those you previously mentioned) quite a bit in the 70’s & 80’s. The requirements were simple: Any defensive perimeter must have DID, MS, and IFOF, which is what will be in any manual from that time period (if they’re still in print). Since the transition to ‘Security Forces’ and more Army oriented infantry operations, which were after my time, I can’t comment on what/where it would be listed in current manuals. In any event, just circling the wagons wasn’t done unless there were several ‘rings’ that provided the listed requirements. The RT was one that did and was therefore good to go. Bottom line: It’s a patrol base or quick perimeter set up as I know it.

    Glad to hear your folks will be discussing the merits or demerits, depending on how you see it. Would be interested in your team’s conclusions via email to

  13. david

    Since this particular formation is unusual and presents some general-wisdom-technical No-No’s (active FOF from the center), I am suspicious of something. Especially since your historical reference is from a Static Fixed Base with: buildings, aircraft, assundry other vehicles, trailers, and misc. structures…

    There may be a significant stretch required to apply this idea to SUT or Light Infantry (highly mobile rather than static). One of my compadres just mentioned that this would readily apply as a MODIFIED WEDGE if the center gunner GOT ON LINE in whatever direction the threat was most presented. But that would mean the formation is limited in it’s growth (so the center guy could get on line rapidly).

    Also, I am dealing with this technique from the perspective of field maneuvers. The basis of the technique you bring forward (“RT”) is based largely on static defense of a base. The two are likely not congruent; at least directly.

    One of the guys from our team brought a lesson for “Break Contact” one training day and tried to teach it. Turned out he was trying to apply a platoon size technique (30 guns and heavy armaments) to a small team (4-6 guns). Needless to say, it did not translate and was embarrassing.

    I will look into this AF airport perimeter and it’s history and also let you know what the guys have to say! Should be full of colorful discussion. You bet, I will forward our findings and conclusions.

    Thanks so much for the perspective and intel.

  14. Defensive Training Group Post author

    With all due respect, your knowledge of AF ABGD capabilities and responsibilities is very

      weak regarding external base defense. ABGD troops dealt with everything up to 5 km outside the wire. 5 clicks is a long way out when you’re on your own, and AF or not, you better have your tactical drills down pat, wouldn’t you agree?

      Strictly static positions on the perimeter went away in the mid 70’s as the AF embraced ‘Distributed Area Defense’ or ‘DAD’. This came about because the Army and Marine Corp told the AF to take care of itself, and the AF could no longer rely on them. We even had our own limited stand-off weapon support when outside the wire: The 81mm mortar teams. AF manned, AF trained. We also had M-2 and 90mm Recoiless and even had Mk-19’s (when they came on line) and Stingers in some applications.

      As to a stretch in application of the RT for a patrol base in the field, it wasn’t when we used it. Now, if you folks find it doesn’t work for you, that’s unfortunate. But then again, to objectively evaluate a TTP, you need to do more than kick it around the team room.

      Glad to have had the discussion, and thanks again for stopping by.

  15. david

    Yes sir. Copy that. I made a few errors here. I ran this technique through the strict filter of what I know and what is common to the civilian use of Light Infantry Tactics.

    What you are offering is good. But my lack of ABGD knowledge base and other limitations of formal military tactics made the learning process here difficult. My apologies. I understand now your approach and can see it’s application.

    Thank you for your patience, you were very professional with your approach to the tactical idea exchange.

  16. Defensive Training Group Post author

    Not at all; that’s why DTG is here — help where we can and provide meaningful exchange of information. You’re welcome to drop notes to the email address any time to discuss/examine anything you find useful here that may not be within the scope of blogpost comment.

Feel free to comment! Debates are welcome, so long as they add to the discussion. Ad hominem attacks, accusations, uncontrolled vitriol, thread hijacks, personal threats, or any comment that otherwise detracts from DTG's stated mission will not be approved or posted. Repeat violators will be banned.

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