Combined Action Platoon (CAP), Vietnam —Part III

By Lieutenant Colonel William C. Curtis, USMC (Retired)

The Viet Cong were always watching.  Always.
The Viet Cong were always watching. Always.

Among many things to remember is that CAPs were a long way from any reinforcements should the VC or NVA attack us.  Phu Bai was only eight miles away, but it may as well have been eighty, as the enemy would only attack in force during the hours of darkness when close air support (attack aircraft and armed helicopters) was not likely to be employed.  There was no plan to rapidly reinforce, by ground, any CAP in 1967. Thus, we were truly on our own —especially at night. With that in mind, we needed to do things that would discourage the enemy from attacking our compound or coming into any BChamlets.  We did this in numerous ways—

  • We continually improved our fortifications. When it wasn’t raining, we filled sandbags and added them to our walls. We constructed more fighting bunkers inside the compound should the enemy breach our outer defenses.
  • We increased barbed wire fencing along the perimeter of the compound—and we were clever about it. Using long, middle, and short length barbed wire stakes, we kept changing our concertina pattern so that every time the enemy studied the configuration, he was presented with a completely new problem. We knew the enemy was constantly watching us. While some CAPs were overrun, we never were.
  • We always had a sentry posted inside the compound; his job was to keep an eye on the surrounding area during hours of daylight —to observe and report any unusual behavior, such as locals pacing off the distance from concealment to the edge of our compound.
  • We put employed Claymore mines within the wire of the perimeter.
  • We pre-positioned additional ammunition, grenades, and pop-ups in each bunker.
  • We acquired a 60mm mortar from the ARVN and illumination rounds from Phu Bai.
  • We sent out a patrol every day; we set up an ambush every night.  Again, the enemy was always watching —and listening— so we never revealed our route of march or ambush location to the Marines at the Phu Bai combat operations center until the last moment, and we never gave this information to the PFs. This made enemy more difficult: they were never quite sure where the Marines were. I would add that we continually changed our patrolling and ambush tactics and I think that our unpredictability frustrated the enemy.

At this time, the primary weapon for Marine infantry was the M-16 rifle. We also had automatic weapons: one 7.62mm machine gun, one .30 caliber machine gun (borrowed from the ARVN), a number of .45 caliber pistols, one 12 gauge shotgun, one 40mm M79 Grenade Launcher, and grenades of different types. As previously stated, we liberally employed Claymore mines as instruments of defense. The PFs were armed with WW II Era weapons: M1 rifles, Browning Automatic Rifles (BARs), and .30 caliber M1 carbines.  The PFs, most of whom were slightly built, favored the carbines because the weapon was light and easiest to carry. The downside, however, was that carbines lacked substantial stopping power.


Douglas AC-47  (a.k.a. Puff the Magic Dragon)
Douglas AC-47 Spooky Gunship (a.k.a. Puff the Magic Dragon)

On call supporting arms was available to Hotel-3 but with the exception of aero-medical evacuation, I never used them. The medevac choppers came in handy for our civilian population (breach-birth, child near death, etc.) and all of these cases ended on a positive note. I didn’t see a need for artillery or close air support because the enemy we faced never exceeded a hundred in number and we always succeeded in surprising them. Whenever we hit the enemy, they always backed away. Another factor was that artillery and air support increased the possibility of a costly mistake—undoing all that we were attempting to do for the local population. On the other hand, had a large force ever attacked us, I would not have hesitated to call for artillery or close air support.

I knew the enemy was always watching us; I knew that if they every discovered a weakness, they would exploit it. Our goal was to keep the enemy off their guard, so we would do the unexpected. For example, we might begin a morning patrol —heading out very slowly and looking very menacingly at everyone and then at some distance from the compound, we would turn around and run back the way we had come, and then proceed out of the village on another trail. The locals would see us, and then suddenly we were gone only to appear at some other (distant) location.

Continued next week—


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Retired Marine, historian, writer.

14 thoughts on “Combined Action Platoon (CAP), Vietnam —Part III”

  1. Continues to be interesting, and recalling Bing West’s The Village.


    1. Curtis is a personal and long term friend of mine. I know he’ll answer any questions you may have about his experience in CAP.


  2. Thank you. Having read The Village I can picture this vividly. Except for the barbed wire stakes. Wikipedia did not help either.

    I found this interesting: “The PFs, most of whom were slightly built, favored the [.30 caliber] carbines because the weapon was light and easiest to carry. The downside, however, was that carbines lacked substantial stopping power.” No kidding!

    Perhaps you could weigh in on this: I’ve been told that a key rationale for downsizing from a .308 to a .223 in Vietnam was the “slight” build of our allies. They couldn’t lug around the heavy ammo. (I notice they don’t want to carry the BAR in this story.) The lighter weight of the cartridge meant you carry more for the same weight and have more firepower in close quarters combat. (Made sense – I never got the impression that Vietnam combat had extended shooting ranges, but I may be wrong.) Yet the VC and army of the north carried .308. How come they didn’t have trouble with the heavier piece? Same size guys.


  3. It is 0030 where this older Marine lives. I plan to answer your questions toot sweet in the morn. BTW, good questions.


  4. Baysider, here is the best response I can give at this time. Before you read, remember, I was never on the inside of procurement of military weaponry…just a user.

    Barbed wire stakes are (or were) made of metal and quite sturdy (heavy). They have a rather “U” shape all along the length of the stake. The short ones are about 3.5 ft long. The medium ones are about 5-6 ft long and the long ones are about 8 feet +.

    Some barbed wire comes in concertina style and can be unloaded and shaken out rather quickly….though it needs to be “nailed” to the ground so bad guys cannot lift it and quietly crawl under. Further it needs supports to maintain its’ height. One role is not really a defense.

    Triple concertina is two rows side by side and connected with a third row on top the first two. More stakes are needed to prevent the enemy from rushing the barbed wire barrier and leaping on it to smash it down with their body weight and their comrades literally running over their body to gain access to a position.

    All this leads to my philosophy of barriers. If one is going to occupy a position for some time, there needs to be barriers. Important Note: They need to be increased all the time and made more formidable.

    So, using a COMBINATION of concertina wire and “regular” wire which came on large spools, we (in CAP H-3) would dig holes to put long and medium stakes in the ground. The Seabees gave me some cement and we’d fill the bigger holes with that.

    There are all manner of barbed wire barriers. We used all I could remember.

    Thus, the enemy (who I always assumed was watching) would be faced with an ever changing problem in terms of attacking the outer barriers of our compound.

    Think new (and more) fences and barriers being put in every week or so.

    Is that enough information on the barbed wire and the stakes?

    AFTER THOUGHT ON THIS: Inside the very thick and getting thicker all the time series of fences and concertina was lots of Claymore mines. You can look that up. Everyone “shoots” Expert with Claymores. Devastating. We also put those zillion candle power aircraft flares mounted with a series of stakes to firmly hold them in place at the height of about 5 feet. A thermite grenade was attached to the top and screwed tightly. If the enemy came, we’d pull the wire to the grenade which would set off the huge BLINDING flare. Of course, we had sturdy tin shields between us and the flares so our guys wouldn’t be blinded, only the enemy. Note: They never attacked my compound while I was there. Could it have been overrun? Yes. However, the cost benefit ratio would have been horrific for the enemy.

    IRT to the fielding of the M-16. I am not sure, but the Army wanted it and the Marines have to piggy-back off other services for weapons, tanks, aircraft and such. Our budget is too small to do otherwise. Added to that is the logistics problem if you have too many different calibers of weapons.

    Recently I read that the reason that the military doesn’t use JHP rounds in combat is that it is “better” to wound an enemy than kill him. Why? It puts a huge burden on other side that has lots of living but wounded. They have to be taken care of with some immediacy. Those KIA can wait. The WIA need help and quickly. This reduces the combat power of a unit if they are caring for their wounded comrades and no longer fighting.

    As for me, I really liked the M-14 with the 7.62 mm round. It was agreed to by all the NATO allies before Vietnam got going. The downside, however, is the ammunition (7.62 mm) is very much heavier….ask any machine gunner (machine guns in infantry units are mostly 7.62.

    When increasing the size of one’s military in rapid fashion – often real emphasis and extended training in marksmanship is lacking. Thus, the infantry and others that fire….fire lots and lots of ammo when in combat and achieve a lower percent of hits than better trained troops.

    I was very lucky to have be shot at by many people that were poorly trained. Carrying the AK-47 and the SKS, they mostly seemed to shoot too high. Not always the case and some units might have been better.

    You’re right in that most combat was within a 200 yard distance. The enemy would – nearly always – wait until we got close and then open fire. They, rightly so, were worried we’d call artillery, mortars and air support to attack them…but, if we were very close it was very much more difficult to do that.

    Now, we see nearly all the military adopting lighter rifles. Most are semi automatic, though some have a switch to go to a three round burst. This saves ammo and increases hits on the enemy. A .223 round, though the bullet is small, has a very high velocity. At the shorter ranges of today’s warfare, it really is better than the heavier weapons of WW II and Korea.

    The U.S. should have provided the South Vietnamese with M-16s and all the gear that we used right from the outset.

    One of very many mistakes in a war that we would have won…except for dumb senior officers and LBJ, McNamara and a Congress that was more interested in re-election and in doing the right thing.

    Semper Fi.

    William C. Tad” Curtis USMC (Ret.)


    1. My thanks to you – I had family in that war–so – appreciate the historical overview of it–


    1. I did a little research and it has to do with when bullets were all lead, i.e. relatively soft and could be worked on by soldiers. This really is, in my view, pretty silly in that with all the number of weaponry/munitions that now exists to kill or do great harm is on a too long list.

      Saying all the above, I could not find anywhere in which decisions on bullet type, size, weight or such was based on any laws or conventions prior to or subsequent to WW I.

      Do you have any information on this that I don’t know about?


  5. Thank you Tad! Mr. B and I found your article and your explanation of my question fascinating. Your comment about tying up more resources with wounded vs. KIA makes sense. Mr. B commented particularly on the intelligent perimeter. That brings up another question: how do friendlies get out? Where’s the balance between defense and sally ports? I think you mentioned 4 outlets and a keep-em-guessing tactic.

    Mr. B was ‘Expert’ with the M-14 and loved the piece. As he says, “a damn sight better than the M1” which he also trained on. The bottom line is a soldier has to have confidence in his weapon. (Notice I did not say ‘or her’ – gads.) I had a boyfriend who used the M-14 or AK47, and when the first M-16’s were introduced (the ones with the gas port problem) their 6-man squad had 3 of them jam in their first fire fight. When their commanding officer learned about this, well, let’s just say that the remaining cache of M-16’s were rendered inoperable by friendlies.

    Looking forward to your next installment.


    1. While there were a number of small well guarded ways out, I choose to mostly use the main gate. I wanted them to know we were always out and about….this, of course, required us to use lots of tricky patrol tactics in daylight and setting into ambush sites once..waiting, the moving again…sometimes as often as 3-4 times…including in the rain.

      I was trained with the M1 also. I only learned to shoot the M-14 when I came back from embassy duty in Rome and Oslo. In those days we only had .38 revolvers with 5 rounds. Now Marine Guards are heavily armed. Tougher to get into an embassy in these days.


  6. Sir, I think Gunny (Chuck) would have been all over this author’s mention of Claymores…

    It never ceases to amaze me how our Marines stand their ground if not attack against a numerically superior enemy. His mention of the WWII-bred M-1 carbine and its favored status among smaller framed Vietnamese was interesting.

    A 442nd veteran who I worked alongside of made a somewhat humorous comment about the BAR. He said there were were a few of these Nisei’s during basic that wanted the BAR because of its macho (I’m paraphrasing.). When it became time to train with one, he made sure it got away from him. He told me he was no fool thinking the Germans would go after a machine gun or BAR first.


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