(by Michael Scudder)
Ontos means "the thing" in Greek. As applied to the Marine's armored vehicle, it could mean "the rare thing".
This armored vehicle made significant contributions to the success of Marine and Army infantry operations in Vietnam, but less is known about the vehicle than any other armored vehicle produced by the US military. Even among military vehicle collectors, the name Ontos often draws blank expressions. The reasons may stem from the fact that the Ontos was produced in small numbers. Only 176 vehicles are known to have been in the Marine Corps at the start of the Vietnam War. Another factor is the Marine Corps quickly disposed of the surplused vehicles; removing much of the hulls and gun mounts. With so few examples of surviving Ontos making it into the hands of museums and collectors, its story didn't get told. There are more surviving WWI tanks today than Ontos.
The Ontos was a relatively light weight tracked armored fighting vehicle that was designed in the early 1950's to destroy the main battle tanks of this era using the firepower from its six 106mm recoilless rifles. Its diminutive size, 12 ½' long, 8 ½ ' wide, crammed three crewmembers into a compartment slightly higher than 4'. It served the US Marines from 1956 until the bulk of them were dismembered in 1970. Its service to the Marine coincided with the Corps's use of the 106mm recoilless rife.
The Ontos would be more than 10 years into its life cycle before it would be tested under fire. The first test would be against the Dominican rebels in April of 1965. The second test was in the environment of Vietnam; and its role would have no relationship to what was originally intended for this fast little tank killer.
If it is true that an army fights its present war with tactics and equipment from its last war; then it is the mark of a successful army to be able to adapt in order to accomplish the new mission. The Ontos and its crews had to convince the Marine Corps leadership that this fighting vehicle had a role in Vietnam. The success, at convincing its leaders of the Ontos's potential, is mixed. The men that made up the Ontos crews attest that it was only at the company level that they convinced leadership of the enormous firepower that could be available to the grunts; firepower that could change the outcome of a firefight.
I am struck at the similarities of the Ontos's role within the Infantry Company and the role of the little Stuart tank used by the Marines in the pacific battles of WWII. Both were lightly armored and venerable to the destruction by weapons above 50-caliber. Both of these vehicles were effective because they were small yet could carry relatively high firepower into an infantry firefight. Their size allowed them to go into areas the larger tanks could not. The 20" wide tracks of the 9-ton Ontos would allow it to go on the soft soils surrounding the rice paddies of Vietnam. They both served as bunker busters. Both vehicles lessened the infantry's causalities by being close to the fight; and could be quickly deployed to overcome an enemy's fixed positions.
The Ontos carried the beehive round that sent out a hundred darts per firing to clean out a jungle of its enemy. There was no other weapon that could clear a jungle for a depth of a ¼ mile like the 106mm recoilless rifle using the beehive round. Artillery shells and bombs effectiveness was cut to the area of a direct hit. The jungle vegetation absorbed both concussion and fragmentation. The other vehicles that mounted the 106mm recoilless rifle were open to enemy small arms fire. The Ontos could expose itself to enemy small arms for the short time it took to empty its guns and depart to a more secure position to reload. It was an armored shotgun and the North Vietnamese Army feared it.
It is no surprise to the veteran of any country's army that weapon systems get misused, unsupplied and/or forgotten by the generals that demanded their development. The Ontos fell into this grouping. Deployment of the Ontos seemed like an after thought to many commanders and the Ontos's parts replacement was a serious concern. It is a testament to the men that manned this small armored fighting vehicle that some important history was written by its participation in Vietnam.
The Ontos was designed in another era for another purpose. Developed to kill tanks; the Ontos found itself outmoded before it was in the hands of its first crewmen. It was left to the men who manned the Ontos to reinvent it; and they reinvested it into a weapon that served the Marine infantryman.
The Ontos crews were pulled from the Marine Infantry Battalions to learn the trades of gunners, radiomen, mechanics and tacticians. The Marine designations for jobs within the infantry battalion were in the series 0300. The Ontos's crews carried variations on these job numbers. Some crewmen were motor transport or track maintenance trained, but most were more likely to be former riflemen. After their tours with the anti-tank units, they were just as likely to return into the battalions from which they came as to be reassigned another anti-tank unit.
The Marine high command was single minded in pitting the Marine Infantryman against the North Vietnamese Army and Viet Cong veterans. They felt, with good assurance, that the individual Marine, coupled with traditional artillery and air cover, could defeat this enemy without any distractions from those weapons not carried to the field by their enemy.
Everyone believed that Vietnam was not conducive for tank operations. If it were, the NVA would have fielded armor. Since tanks were not fielded by the NVA, then there was little use for the small anti-tank known as the Ontos also known as a"pig".
The Marines carried its' M48A2 tanks and Ontos into the fields of battle, but they didn't command the focus of the Regimental and Battalion Commanders as did the traditional attachments such as the 81 and 4.2 mortars, 105mm artillery and close air support.
The Ontos's deployment was often a knee jerk decision by Battalion Commanders. They were used mostly as perimeter defense with some convey duty.
Vietnam was run by our politicians; with rules of engagement that totally distracted the military commander. Our air power was forbidden to knock out the surface to air missile sites that depleted their ranks. In early Vietnam, the enemy could retreat to areas forbidden to US forces. These rules as applied to the Ontos crews decreed that all major caliber weapons had to secure Battalion authority before being loaded or fired. The early Ontos crews were expected to go into combat areas unloaded. Later, they could have 106 rounds in the guns, but had to secure authority to fire. These rules would have given nightmares to WWII or Korean War veterans.
If the Marine Commanders ignored the attributes of the Ontos, the NVA didn't. In almost all my interviews with Ontos Crewmen, one point was brought up. The NVA was frightened of the Ontos and would avoid contact if possible. Most contact between NVA and the Ontos was inadvertent on the part of the enemy.
The Ontos project was awarded to the Allis-Chalmers' farm machinery Division of Wisconsin around the early part of November 1950. The Allis-Chalmers engineering section was comprised of about 50 to 60 engineers; 90% of which would eventually work on the development of the first prototypes. All the prototypes were constructed in the Agricultural Assembly Plant in LaPort, Indiana.
The project was first envisioned by the government to be an air transportable tank destroyer capable of being lifted by the cargo aircraft of the 1950's. The contract was to be for 1000 vehicles to be delivered to the Army. In 1953, the army would refuse to accept delivery of the Ontos. At this point the Marines accepted delivery of about 300 vehicles.
The government Ordinance Command, represented by Chief Engineer Carl Holmyard, delivered only one page of specifications. The specifications demanded that the vehicle would be powered by the same GMC six cylinder gas engine that was standard for the 2 ½ ton military trucks of the day and a front mounted Allison cross drive transmission that would carry power to the tracks. The remainder of the specifications restricted the outside dimensions and weight so as to be air transportable.
The project was classified "Confidential". This is the lowest security classification for government work, but it still required that the prototypes be built in a walled off section of the Agricultural Division Assembly Area. The government would accept the prototypes for testing only after the machines had 50 hours of running time. This required the engineering section to come to the plant on weekends and drive the prototypes around the grounds of Allis-Chalmers.
The Ontos had two large arms that held the six recoilless rifles. These arms were joined to a shallow turret. This entire assembly was cast in armored steel. The early prototypes could swing the guns less than 15 degrees left and right. The production Ontos was modified to turn the guns 40 degrees left and right.
The welding of the Armored hull was a problem for Allis-Chalmers. It took the failures of several prototypes to develop the proper welding techniques.
The first prototype Ontos had a track system similar to that used on the self propelled artillery vehicle called the Scorpion. This track system was later changed. This first Ontos prototype is still in existence and in the hands of Mr. Fred Ropkey.
The later and final track system and suspension was of a new design. Each track consisted of two sections of rubber; 48" long with steel drive teeth in the center. Twenty-inch wide steel grousers held the rubber and the drive teeth together. It took 5 sections of track to make up a complete track. A well-motivated crew could accomplish a track section replacement in about 1½ hours. One crewman told me that a crew made a track repair in 42 minuets.
The suspension system was designed so that no mechanisms intruded into the already small interior of the fighting compartment. The road wheels hung on torsion bushings that were attached to the sides of the hull. There was much development in the special rubber compounds for the bushings.
The rubber bladder gas tank was mounted in the front of the vehicle directly behind the glacis plate. It was cast of rubber and contained a tube-shaped void through its center to allow the left drive shaft to pass through the fuel tank on its way to the left drive sprocket.
Allis-Chalmers had developed a deep water fording provision for the Ontos that was not accepted by the Marines. It consisted of a waterproof covering for the engine. The motor would stay dry while fording. The fording gear had to be carried and installed on the Ontos prior to fording.
One of the problems that had to be overcome by Allis-Chalmers involved the track alignment. The lower chassis was constructed as a weldment. The distortion involved in the welding process caused the suspension to become out-of-line; and so the track would be thrown. Machining the lower hull, where the track suspension parts bolted to the hull, finally solved the problem.
Allis-Chalmers also developed a personnel carrier based on the Ontos track design. The personnel carrier had one additional 48" track section. No photos are known to exist of the personnel carrier prototype.
Much of the engineering work was completed in 1950 during a two-week design marathon. The Marine Corps continued to test the vehicles for the next six years until the vehicle was accepted in late 1956. A review of the chief engineer's notes for 1957 through 1959 showed a continuing series of revisions. These notes, of Chief Engineer Craig Cannon, referred to a major revision of the Ontos called the "1960 project". Some of the proposed revisions called for an aluminum amphibious hull and two 105mm recoilless rifles (designated as T237 guns) fitted with a cylinder similar to a revolver pistol. This change would have allowed multiple firings of the two guns without the need for a crew member to reload the guns from outside the vehicle. Another major revision would involve the replacement of the engine with a turbine engine. The "1960 Project" was never accepted.
One of the early tests involved the acceptance of the aiming system of the six gun turret. Part of the test included the firing of all six guns at once. The test vehicle was taken to the Aberdeen testing facility that had been built for the testing of the 106 recoilless rifle. No one envisioned the effect of six of these weapons going off at once, least of all the people who designed the testing facility. The backblast from the firing knocked bricks out of a nearby building and knocked the rear windows out of several cars.
Allis-Chalmers was to later refurbish the Ontos: removing the 6 cylinder engines and replacing them with the 361 cubic inch Chrysler V8. The change over involved redesigning the armored engine covers with additional venting. It is believed that, of the 300 delivered units, only 176 Ontos were refitted.
THE ONTOS ARMORED HULL
The 51"wide glacis plate of the Ontos is 1" thick. The glacis plate forms the front of the hull and would protect the driver and transmission from ground level to 27"in height. The side plates that hold the track suspension parts and form the sides of the crew compartment are slightly heavier than 1/2" thick. The floor of the fighting compartment is ¼" thick of non armored steel. The majority of the remainder of the hull is formed from ½ thick armor. The front engine covers are cast of armored steel and its louvers have a 3/8' bead formed on the inside lip of each louver to defeat the entry of small arms fire from entering the engine compartment.
It has been speculated that the Ontos was top heavy and tended to overturn easily. I found that with the top hull, gun mount and guns removed, the vehicle still weighed in at more than 11,000 pounds. This 11,000 pounds would be contained within the height of the tracks (34"). I therefore doubt that the Ontos was seriously top heavy. Crewmembers have told me that the vehicle would slip sideways if traversing a steep hill before it would roll over.
The 106MM Recoilless Rifle Firing System
The Ontos had the ability to fire its 106 recoilless rifles one at a time or as many as all six guns at once. Four of the six guns had 50 caliber spotting rifles attached. The flight of the 50 caliber spotting round approximated the flight of the 106 round. This round was constructed as a tracer with a smoke puff that appeared on impact. The firing of the weapons was directed by the gunner; who had a seat to the rear of the driver and engine. The gunner would often first fire the spotting round at the desired target and watch its flight. Often, even prior to the spotting round hitting the target, the 106 round would be sent on its way. The maximum effective range for the 106 round was 3,000 yards. The 106-MM rifle was generally considered a direct fire weapon, but the crews were taught, and used, indirect fire at targets not within sight of the gunner.
The 106-MM recoilless rife is more than 11' long and weighs about 288 pounds each. The turret of the Ontos had to carry this 1,700 plus pounds over uneven ground. The strain on the gun mount required the crews to realign the guns from time to time.
Two of the six rifles were designed to be easily removed from the vehicle and used with a ground mount should it be required.
THE ONTOS ORGANIZATION
There were three men to an Ontos: driver, commander/gunner and loader. If the Ontos was carrying a lot of ammunition and/or other gear, or if the weather was extremely hot, you could find the loader sitting on the driver's hatch, riding on the machine gun crossbar or riding in the platoon's ¾ ton Dodge truck that often escorted a platoon movement. The Ontos could and did drive with the rear doors open on occasions. This mode of travel would roll road dust into the interior making the crew look like pigs. For this reason the crews usually referred to the Ontos as a "pig".
The training of the crew varied as the demands of the war changed. The early crews, prior to March 1965, were trained at Camp Horno in the home of the 1st Marine Division, Camp Pendelton on the coast of California near Los Angeles. The training of later crews were assigned to units that trained them in the field. They had to learn: vehicle maintenance, small arms, tactics and direct and indirect fire. All Marines were trained in small arms, but the Ontos crews also carried a sub-machine gun that was not used by most Marine units. They also had to know how to operate the three main radios and intercom. Some of the Vietnam assigned crews went to the firing ranges on Okinawa for extensive day and nighttime firing of the 106MM rifles.
The Ontos crews were required to replace the 48" long sections that made up the track. They also tightened the track adjustment when a track was repaired or when a series of hard turns stretched it. An Ontos mechanic was assigned to each platoon, but the crewmen had to assist to keep the machines running. The platoons were often separated when assigned to infantry units. The platoon mechanic was often unavailable to make a repair when needed. Replacement parts were often rare or non-existent. Many Ontos were turned into parts vehicles due to poor parts supply.
The Ontos platoons were organized into heavy and light sections. There were three Ontos in a heavy section and two Ontos in a light section. There were three platoons to a company; and three Companies to an Ontos Battalion. The 1st and 3rd Ontos Battalions saw action in Vietnam. The machines were in Vietnam from early 1965 to mid 1969. There is some evidence that at the end of 1965 there were 65 Ontos in Vietnam. If this figure is correct it may have represented 45 Ontos of the 3rd Marine Anti-Tanks and a lesser number from the 1st Marine Anti-Tanks; as some of the machines were aboard ships in a standby mode awaiting to be deployed in any hot spots that arose.
The Ontos crew carried 6 of the 106MM rounds in their guns. They carried 8 shells in the rear storage area under the rear doors and 4 rounds in a rack located in the right rear of the vehicle. The loader would dismount and reload from this ammo locker. The interior of the vehicle may carry additional shells depending on the situation. I interviewed an Ontos platoon Sgt. that removed both the driver's seat and commander's seat and piled 30 additional shells into the cramped space. He sat on the ammo while driving or firing the weapons.
The crew also carried an M-3A1 submachine gun (also known as the grease gun or SMG) and Colt 45 automatic pistol (worn in a shoulder holster) with 250 rounds, 1,000 tracer rounds for the 50 caliber M8 spotting rifles, and 1,000 or more rounds for the 1919A4 Browning machine gun. Many of the crewmen carried personal weapons. Some of the personal weapons included shotguns and captured weapons such as the Thompson submachine gun, AK-47 and SKS communist made rifles as well as the French made submachine guns. One crew, known to me, also mounted a 60MM mortar on the front plates of the Ontos.
The Marine Infantry Battalions were armed with the M60 machine gun during this period. For some unknown reason, the Ontos continued to carry the older light Browning machine gun. Some of the crews had the option of changing to the more modern, fully automatic weapon, but opted for the Browning. The older Browning had a reputation to require fewer barrel changes from heavy use. The Browning machine gun was mounted on a pipe support attached to the gun mount/turret. It could be fired manually or remotely from inside the Ontos by way of a foot pedal.
What happened to the Ontos?
The Marines deactivated the Ontos from Vietnam in May 1969. A few of the Ontos were left in Vietnam and turned over to an Army Light Infantry Brigade near Tam KY. The Army ran them until they ran out of replacement parts. They then made them into fixed bunkers. The remainder of the machines in Vietnam were loaded into ships in May of 1969 for return to the US. The crews were reassigned to various Marine Infantry Battalions.
Once the machines were returned to the US, their top hulls were cut off and many of the chassis were sold for construction equipment or given to local governmental agencies for rescue work.
Ontos known to the author to still exist.
The Fort Knox Kentucky museum has an Ontos on outside display.
The Rock Island Arsenal Museum in northern Mo. Has an Ontos on outside display in an area called Memorial Park.
The Aberdeen Proving Ground has an Ontos in an outside display area.
The 4th Marine Tank Battalion has an Ontos that is not on public display in San Diego.
An Ontos is maintained in an outside display area at Camp Atterbury along with 30 to 40 other military vehicles. The outside museum is located along Hospital Road near Highway 65 about 30 south of Indianapolis, Indiana.
Another two Ontos are in American Heritage Park; a private outdoor Museum near LA. These Ontos do not have their 106mm rifles. The park is 15 minutes from LA on highway 60 in South El Monte, California. Mr. Craig Michelson of American Heritage Park said he judges his vehicles to be 80% complete.
The author bought seven chassis that were given to the North Carolina Forestry Service. Four of these vehicles were fitted with roofs and side cages and used for fire fighting. Three of the remaining vehicles were used as parts suppliers for the running chassis.
Another chassis I purchased had been converted into a test-drilling machine. I am presently attempting to build two complete examples from my four chassis.
Four of my seven chassis were given to Dave MacGillivary. Mr. MacGillivary is a retired career Marine that uses his extensive collection of military vehicles for movie rentals. Mr. MacGillivary hopes to assemble a vehicle for movie rentals.
A private collector from Boron, California has a complete Ontos and a parts chassis.
Mr. Fred Ropkey, from Indianapolis, Indiana, owns the first prototype Ontos, a later model Ontos and a parts machine.
The Marine Corps Museum in Washington DC has completed the restoration of an Ontos. Unfortunately this vehicle will be mothballed until their budget allows for the construction of a display area.
There is an Ontos on outside display at the Navy Facility at China Lake, Calif. Permission to enter the facility must be requested at least 24 hours prior to a visit.
There is an Ontos on outside display at the Marine Base at 29 Palms, Calif.
Rememberances of the Ontos from its Crewmen.
Joseph Androlowicz (USMC Retired MSgt.)
(Stories compiled from e-mail messages)
Joe Androlowicz's career almost mirrored the adoption of the 106mm recoilless rifle and its changes on the antitank units of the Marines. Joe also rode the Ontos from its earliest assignments to its decommissioning in 1970.
Prior to the 106mm recoilless rifle being adopted as the antitank weapon of the Marines, the 75mm recoilless rifle was the antitank choice. In 1958 Joe was with the 4.2 mortar section. At this time the big mortars were considered an infantry weapon. Later when the 4.2 mortars were assigned to the artillery, Joe was reassigned to the newly formed anti tank sections. This reassignment coincided with the adoption of the 106-mm recoilless rifle as the Marine's anti tank weapon. Joe's first anti tank assignment was with 1st Battalion, 8th Marine Regiment, at Camp Lejune, NC. At this time the 106 had been mounted on a modified M38A1 jeep.
In 1959 Joe was involved in the testing of mounting the 106 on the M274 mechanical mule. The mule was a 900 lb. fat tired off road machine that was designed as an ammunition carrier. The mule with the 106 was considered an antitank weapon, but was used as a direct fire weapon that did good service in this configuration against everything but tanks.
In 1961 he was assigned to the Ontos as Platoon sergeant, 1st platoon, A Company, 1st Marine Division at Camp Pendelton, California.
In 1965 Joe found himself in Chu Lai, Vietnam. They were called out to support infantry by destroying fortified villages and performing convoy duty. The Ontos platoons were respected for using their guns against any sniper fire even though Regimental permission may not have been secured. Many of the field commanders warned the Ontos crews to secure Regimental permission, but most commanders still covered for the gunners when the fire fights developed too fast to get it.
The Ontos crewmen had to defend the stripping of the Ontos's 30 caliber machine gun against unit commanders that just wanted an extra automatic weapon.
Some commanders wanted to use the Ontos as a minesweeper. This exposed the vehicle to destruction. On one occasion Joe walked in front of his vehicle to show contempt for the order.
Joe's outfit once modified an Ontos by mounting a 50-caliber M2 machine gun to replace the 30 caliber. They then removed all but two of the 106 rifles. The vehicle made a great assault vehicle.
Joe's Ontos was destroyed by a remotely triggered, buried 105 MM artillery round. This occurred near a fishing village outside of the Air Base at DaNang. A heavy and light section of Ontos was working without supporting Infantry when the Ontos was blown up. Joe was sitting on the top of the turret using a radio when the machine got hit. Joe was blown off the machine onto the road in front of the Ontos. He sustained shrapnel in his right thigh. The driver lost hearing and had debris in his face and eyes. The commander soiled his pants. The Ontos lost its right track. The track ended up 15 feet behind the machine. It also lost the front two road wheels and drive sprocket. A small hole was found in the hull.
As a result of the detonation of the 105 shell, the wire that had triggered the explosion was lifted and exposed on the road. The wire was easily followed back to the women that had triggered the mine. She was armed when found and so was killed by the crews of the remaining two vehicles. About a half-hour later the men of the village (about 150 men) surrendered to the Ontos platoon. The 14 crewmen had to guard the 150 prisoners until they could be relieved the next morning
The Ontos platoons often did outpost work by setting up a good observation point and look for targets of opportunity. It was a common route for Joe's platoon to patrol from the air base at Chu Lai to hill 69 about 10 miles north of the air base. From hill 69 they could observe the entire valley. About the 3rd or 4th visit to the hill the second Ontos crew heard a horrendous metal to metal screech. The noise came from the steel track bars (grousers) rubbing on the fuse of a buried bomb being used as a road mine. The crew did enough digging around the fuse to realize that the bomb was huge. A call was made to the combat engineers who used towing cables to slowly pull the Ontos off the bomb/mine. The engineers then uncovered a 500-pound bomb attached to the fuse. The bomb was exploded in place. From the size of the hole it left, there was little doubt that, if detonated, the bomb would have destroyed the entire platoon of five vehicles and crew. It taught the crews of this platoon that spacing between tracks would forever after be observed.
PIG, in reference to the Ontos, may sound like a derogatory term, but it could have been worse. In 1960 the 2nd Marine Division performed an amphibious landing at Onslow Beach. President Kennedy and other VIPs were there to observe the landings. A static display of tanks and Ontos was observed by President and a Colonel that later related the story. President Kennedy commented " what a weird little bugger that is". Most crewmen I have spoken to would choose "pig" to "weird bugger".
Dennis Richardson (Former Captain)
(From a telephone conversations)
During operation PEGISIS, then LT. Richardson found himself leading a platoon of "pigs" on this operation to clear the road to Khe Sanh. The siege of Khe Sanh had been broken, but the road leading to the base had to be cleared. LT Richardson was placed under the Battalion Commander of 2nd Battalion 3rd Marine Regiment 3rd Marine Division. The road leading from the Marine Base at Camp Carroll to Khe Sanh would take about a week. The Ontos would stay close to the road while the infantry swept the steep hills. As the road got closer to Khe Sanh, the effects of the massive B52 bombing showed on the terrain. The once heavily forested hills looked like a moonscape as most of the trees were blown down.
In a conversation with the Battalion Commander, LT Richardson pointed out a lone pine tree that had survived the bombings. The Battalion Commander said the Ontos couldn't hit the side of the hill much less the lone pine tree that sat about 1500 yards away. Lt. Richardson bet the commander $1.00 that his crew could mercy kill the pine on its first shot. The LT picked a good crew for the shot and the deed was done as ordered. After the tree fell, the commander quickly departed without leaving a penny in his wake.
Later at a Battalion meeting the chaplain told the gathering that he had noticed a rise in gambling going on within the battalion, even within the highest levels of command. The commander showed concern. The chaplain added that low morale was accompanying the gambling, as some debts were not being paid. The Battalion Commander got the message and stalked out of the meeting to return with a US dollar that was given to the LT.
The commander asked the chaplain if that would end the morale problem.
(from an e-mail)
The Ontos was not a good place to be if you hit a mine I took a lot of small arms fire from all sides and the sloped plates combined with all the extra junk we carried helped deflect a lot of rounds or softened the blow. When a round hit the back doors the loader would have a heart attack; and you should have heard the comments if I said get out and change rounds in the tubes! (joking of course).
I went in country in 66, but to 3rd recon. I didn't go to AT's (an Ontos unit) until February 67.all (training) was ojt (on the job training) in the field and with my platoon at Camp Carroll. I didn't really feel comfortable until after went back to Okinawa and got to shoot all (the 106MM rounds) I wanted on the range.
W. B. Blanchard
The tracks were the most difficult part of the "Thing". I recall that the track bolts were a SOB to get loose. The sand and dirt wore down the head to where a normal 12 point socket would not work. I recall us having friends and family send us 6 point sockets. We spent many,many hours with the bolts and the sorry.track jack. The worse memory I can recall is to have a track broken in a deep rice paddy. Then have to pull the Ontos and its track dragged out by an Amtrac (tracked amphibious vehicle). (this ordeal) was followed by many hours of trying to pull the vehicle back onto the track. Works good on concrete with one Ontos pulling the vehicle and another holding the track. Try it in sand and you will need another to pull and a lot of luck.
Parts were what you cannibalized from others. I also remember one other area of problems with the Ontos. It was the armor plate bolts. I guess someone thought that using fine threads on the bolts was a good idea. Yeah right, with dirt and sand, it was often the case that no more than the four bolts could be installed. This to me was of great concern. The Ontos, as with all vehicles, were the constant target of the clever VC mine. I spent much time riding on the top (sitting on the round pipe that held the 30 cal MG). Most of the time thinking of being blown off the vehicle then have that dammed armor plate land on me. Mines took 4 of 5 vehicles during my 13 months.
Mr. Blanchard reminded me that the Ontos crews had more weapon cleaning than any other crew served weapon. The three man crew had to clean six 106-mm recoilless rifles, four 50 caliber spotting rifles, one 30 caliber machine gun, one 45 caliber submachine gun as well as clean their personally issued 45 caliber pistols and whatever unofficial weapons they may have carried.
(from an e-mail to Ben Weaver- whose brother died in an Ontos, May 65)
Dear Mr. Weaver
..As for the Ontos, as a ground pounder (Marine Infantry) from Vietnam and a survivor of Operation Starlite with Hotel Company 2/4, I can only say that the Ontos was THE most impressive weapon on that operation. When Charlie had us pinned down in that murderous crossfire and those Ontos rolled in and opened up with the 50's and those six 106's, you would have thought that the entire Marine Corps had landed. Charlie was going in every direction they couldslipping and slidingand not in mud either.
In my recollection of events, it was the Ontos that actually blasted a hole in the hedgerow so the big tanks could join in on the battle and let loose with a few well placed "streams" from a flame tank. If it weren't for Ontos intervention, we would have lost what little cover we were able to hold onto at that particular time of the battle.
Granted, they were light and at times a hindrance to the big boys, but all-in-all I don't think you will find a true Marine grunt that didn't appreciate an Ontos or two hanging around. My philosophy was always akin to the fact that I would always rather have an Ontos that moved rather quickly when you needed them to, with those six big 106 rifles, then one medium or heavy tank with I big howitzer. I know my future wife and children sure were happy that they were around.
(from a telephone conversation)
Tom's first tour in Vietnam was as a sniper with H&S Company, 9th Marine Regiment. He landed in DaNang in March 1965. During this tour he attained the rank of Gunnery Sergeant prior to attending Officers' Training School and receiving a commission. He returned to Vietnam with then Lt. Dennis Richardson and was assigned to the 1st Marines Anti Tank Battalion. He stayed with the anti tank battalion for about one month before volunteering for 1st Marines Force Recon.
When the battle of Hue began, Tom was ordered into the city with a pick-up platoon of 14 men of Force Recon to protect some combat engineers that were attempting to rebuild a destroyed bridge. The engineers encountered too much enemy fire to complete their mission and so Tom set up an observation post on a steep hill that overlooked one of the main entrances of Hue. There was a small pagoda near the summit. His team had several M60 machine guns and M79 grenade launchers and felt they could discourage any NVA from attempting a serious assault on the hill. From this position the team called in artillery fire on buildings occupied by NVA in the city.
The 101st Airborne sent units into Tom's area to attempt to cross some open ground prior to entering the city. The first two patrols of Army troops sustained very heavy casualties attempting to cross the open area. The Army units then called in supporting fire from 155 mm and 8" artillery as well as support from fixed wing and F-4 aircraft. The supporting fire was impressive, but it didn't stop the NVA from returning fire from the city.
Lt. Riggins found a single Ontos and driver and convinced the driver that his Ontos could climb the steep hill to the pagoda if Riggins would climb the hill in front of the machine acting as eyes for the driver. Tom remembers the Ontos was well worn out by this time.
Once on top of the hill, The Ontos provided well-aimed fire into the windows of the buildings that housed the NVA. Lt. Riggins had the range well calibrated since he had been calling in artillery fire for several days. The range was 2500 yards.
The Ontos was knocking out NVA positions with each firing. The recon team did its best to hand carry ammo to the Ontos, but it was a laborious task lifting the 37 pound rounds up the steep hillside to the Ontos. They learned that they could force the NVA from some of the buildings by firing the M8 50 caliber spotting rifle through the windows and thus notifying the NVA that their demise was near.
The Ontos did in a short time what the artillery and air units couldn't. It cleared the open area so the army units could enter Hue.
My conclusions on the Ontos are based on my conversations/correspondence with two design engineers of the Ontos, formerly with Allis-Chalmers, sixteen former crewman of the Ontos, and my restorations, to date, working on the four machines on my property. I can also rely on my poor memory of the machines as I served as a grunt in the Marines.
My remembrances of the Ontos include being impressed with the smooth mellow tone of the engine and exhaust, as the machine would accelerate down a road. The transmission shifted cleanly. I was a former hot rodder prior to joining the Marines and the engine/transmission combination reminded me of the highly modified hydomatic transmissions being used on the drag strips of the early 1960's.
I also remember the lightly sprung suspension. The suspension had more travel to it than the main battle tank M48. It looked bouncy.
I am amused at one of the major criticisms of the Ontos that goes like this: the 106-mm recoilless rifle gives its position away when fired due to the excessive smoke, noise and dust raised at its backblast.
The crews were trained and common sense dictated that after firing the guns the machine must move. The technique was call "shoot and scoot". I can't think of a major weapon that doesn't give its position away when fired. I don't remember silencers on artillery or tanks.
There was consensus among many crewmen that the tracks were weak. The steel grousers broke. The tracks were assembled with small bolts whose heads tended to round off when operating in sand.
The turret/gun mount could have been made heavier as it flexed from the weight of the six guns bouncing over uneven ground.
Another valid criticism was the need to have the loader leave the relative safety of the hull to reload the recoilless rifles from outside. When the Ontos were working in groups in a confined area, the crews had to watch that a backblast from one Ontos didn't kill a loader from another Ontos reloading outside his machine.
The Ontos was in late middle age when it went to Vietnam. The machine proved its worth when it was at the end of its life cycle and the 106-mm recoilless rifle was about to be replaced.
It proved it could be effective using indirect fire when it joined with the M48 Main Battle Tanks in repulsing the only major ground attack at the siege of Khe Sanh. The Ontos were dug into pits and fired at an enemy unseen by the crews.
It proved to be a major street fighter in the narrow alleys of Hue. Its guns blasted an entrenched enemy from buildings 3,000 yards away as well as point blank range.
By the time this "weird little bugger" got its recognition, its guns would be obsolete and its parts supply was exhausted. The mechanics did amazing feats to keep the machines operating by sacrificing one machine to keep two running. The 3rd Antitank machines were in horrible shape and the 1st Antitank Battalion machines were not much better when they had to fight the largest battle the Marines fought in Vietnam in the battle of Hue. After the losses of machines and men in Hue, the Ontos was worn out. Their crews faded back into the infantry and the little machines were returned to California to be disposed.