What was striking about it was the way it had flattened a parked car when the tank's driver goofed during a Christmas Parade in Chicago. That picture proved to me that the power and lethality of a tank are out of all proportion to the size of the package.
I learned a lot more about tanks in 1970 when I was assigned to the 11th Armored Cavalry Regiment in Viet Nam.
Normally, interrogators like me were in slots at brigade level or higher. The Eleventh Cav was unusual in that each of its three squadrons in the field had a Battalion Intelligence Collection Center—pronounced like the pen—of four to six men. After a week or two at the rear-echelon headquarters of my unit, I requested assignment to a BICC. A few weeks later, I joined Second Squadron in Cambodia.
Our BICC had a variety of personal and official gear—the tent was our largest item—which fitted into a trailer about the size of a middling-big U-Haul-It. We didn't have a vehicle of our own. When the squadron moved (as it generally did every week or two), the trailer was towed by one of the Headquarters Troop tracks; and we, the personnel, were split up as crew among the fighting vehicles.
The tanks were M48s, already obsolescent because the 90mm main gun couldn't be trusted to penetrate the armor of new Soviet tanks. That wasn't a problem for us, since most of the opposition wore black pajamas and sandals cut from tire treads.
M48s have a normal complement of four men, but that was exceptionally high in the field. In one case, I rode as loader on a tank which would have been down to two men—driver and commander—without me. The Eleventh Cav was at almost double its official (Table of Organization) strength, but the excess personnel didn't trickle far enough from headquarters to reach the folks who were expected to do the actual fighting.
While I was there, a squadron in the field operated as four linked entities. Squadron headquarters (including the BICC) was a firebase, so called because the encampment included a battery of self-propelled 155mm howitzers—six guns if none were deadlined.
Besides How Battery, the firebase included Headquarters Troop with half a dozen Armored Cavalry Assault Vehicles—ACAVs. These were simply M113 armored personnel carriers modified at the factory into combat vehicles. Each had a little steel cupola around a fifty caliber machine-gun and a pintle-mounted M60 machine-gun (7.62mm) on either flank.
There were also a great number of other vehicles at the firebase: armored personnel carriers modified into trucks, high-sided command vehicles, and mobile flamethrowers (Zippos); maintenance vehicles with cranes to lift out and replace engines in the field; and a platoon of combat engineers with a modified M48 tank as well as the bulldozers that turned up an earthen berm around the whole site.
Apart from these headquarters units, the squadron was made up of a company of (nominally) seventeen M48 tanks; and three line troops with twelve ACAVs and six Sheridans apiece. The Sheridan is a deathtrap with a steel turret, an aluminum hull, and a 152mm cannon whose ammunition generally caught fire if the vehicle hit a forty-pound mine.
Either a line troop or the tank company laagered at the firebase at night for security. The other three formed separate night defensive positions within fire support range of How Battery.
I talked with a lot of people in the field, and I got a good firsthand look at the way an armored regiment conducts combat operations.
When I got back to the World, I resumed my hobby of writing fantasies. I'd sold three stories to August Derleth in the past; now I sold him a fourth, set in the late Roman Empire. Mr. Derleth paid for that story the day before he died.
With him gone, there was no market for what I was writing: short stories in the heroic fantasy subgenre. I kept writing them anyway, becoming more and more frustrated that they didn't sell. (I wasn't real tightly wrapped back then. It was a while before I realized just how screwy I was.)
Fortunately, writer friends in Chapel Hill, Manly Wade Wellman and Karl Edward Wagner,suggested that I use Viet Nam as a setting. I tried it with immediate success, selling a horror fantasy to F&SF and a science fiction story to Analog.
I still had a professional problem.There were very few stories that someone with my limited skills could tell which were SF or fantasy, and which directly involved the Eleventh Cav. I decided to get around the issue by telling a story that was SF because the characters used ray guns instead of M16s . . . but was otherwise true, the way it had been described to me by the men who'd been there.
The story was "The Butcher's Bill," and for it I created a mercenary armored regiment called Hammer's Slammers.
The hardware was easy. I'd spent enough time around combat vehicles to have a notion of their strengths and weaknesses. Hammer's vehicles were designed around the M48s and ACAVs I'd ridden, with some of the most glaring faults eliminated.
All the vehicles in the field with the Eleventh Cav were track laying; that is, they had caterpillar treads instead of wheels. This was necessary because we never encamped on surfaced roads. Part of any move, even for headquarters units, was across stretches of jungle cleared minutes before by bulldozers fitted with Rome Plow blades.
The interior of a firebase was also bulldozed clear. Rain turned the bare soil either gooey or the consistency of wet soap. In both cases, it was impassable for wheeled vehicles. Our daily supplies came in by helicopter.
Tracks were absolutely necessary; and they were an absolute curse for the crewmen who had to maintain them.
Jungle soils dry to a coarse, gritty stone that abrades the tracks as they churn it up.When tracks wear, they loosen the way a bicycle chain does.To steer a tracked vehicle, you brake one tread while the other continues to turn. If the tracks are severely worn, you're certain to throw one.
If they're not worn, you may throw one anyway.
Replacing a track in the field means the crew has to break the loop; drive off it with the road wheels and the good track while another vehicle stretches the broken track; reverse onto the straightened track, hand feeding the free end up over the drive sprocket and along the return rollers; and then mate the ends into a loop again.
You may very well throw the same track ten minutes later.
Because of that problem (and suspension problems. Want to guess how long torsion bars last on a fifty-ton tank bouncing over rough terrain?) I decided my supertanks had to be air-cushion vehicles. That would be practical only if fuel supplies weren't a problem, so that the fans could be powerful enough to keep the huge mass stable even though it didn't touch the ground.
I'm a writer, not an engineer. I didn't have any difficulty in giving my tanks and combat cars (ACAVs with energy weapons) the fusion powerplants without which they'd be useless.
Armament required the same sort of decision. Energy weapons have major advantages over projectile weapons; but although tanks may some day mount effective lasers, I don't think an infantryman will ever be able to carry one. I therefore postulated guns that fired bolts of plasma liberated—somehow—from individual cartridges.
That took care of the hardware. The organization was basically that of the Eleventh Cav, with a few changes for the hell of it.
The unit itself was not based on any US unit with which I'm familiar. Its model was the French Foreign Legion; more precisely, the French Foreign Legion serving in Viet Nam just after World War Two—when most of its personnel were veterans of the SS who'd fled from Germany ahead of the Allied War Crimes Commission.
The incident around which I plotted "The Butcher's Bill" was the capture of Snuol the day before I arrived in Cambodia. That was the only significant fighting during the invasion of Cambodia, just as Snuol was the only significant town our forces reached.