Hello all, here is today's article posted on TheArmoryLife.com. It is titled “The Noble (but Doomed) M551 Sheridan in Vietnam” and can be found at https://www.thearmorylife.com/m551-sheridan/.
The Noble (but Doomed) M551 Sheridan in Vietnam
- Thread starter Mike H.
- Start date
Talyn
SAINT
The word "doomed" is a silly characterization. Any light-weight armored vehicle has its vulnerabilities, and even the M48 tanks in VN were knocked out. The M551 stuck around well after VN, serving until 1997.
The Sheridan was praised for its performance in Panama, and the Sheridan suffered no mechanical breakdowns in combat and performed extremely well in Desert Storm and Desert Shield in it's intended role as a Armored Reconnaissance/Airborne Assault Vehicle.
The Sheridan was praised for its performance in Panama, and the Sheridan suffered no mechanical breakdowns in combat and performed extremely well in Desert Storm and Desert Shield in it's intended role as a Armored Reconnaissance/Airborne Assault Vehicle.
Cedric
Custom
I served on Sheridans on the East West German border in the late 70s. Admittedly there were problems during VN, but like any weapons system, there were improvements. The big thing that stuck out to me was saying it had "a finicky track." Umm.. no. It was a very dependable track and suspension and rarely gave us problems compared to the M60 series. We could go were the heavies wouldn't dare follow. One memorable case at Hohenfels maneuver area, a column of M60s and Sheridans moved out at night in near blizzard conditions with compacted snow and ice on the tank trail. The heavies tried to climb a grade and came spinning down out of control. Meanwhile, our cav troop went up the hill no problem.
Another error is while the hull armor was aluminum, the turret was rolled homogeneous steel with steel belly armor. Design and engineering development never stands still. As far as fire control goes, we were the first to get laser rangefinders (although not integrated with the fire control) years ahead of the M60 series. It also was one of the most dependable systems on the vehicle. The gun was not a smooth bore, but rifled. Our master gunner equated the 152mm more akin to a direct fire howitzer in contrast to an M60s gun. We were inherently more accurate round to round.
There were other things I could mention, but as Talyn said, the article just skims the surface of the vehicle's performance and history and the author certainly can't call it a failure.
Another error is while the hull armor was aluminum, the turret was rolled homogeneous steel with steel belly armor. Design and engineering development never stands still. As far as fire control goes, we were the first to get laser rangefinders (although not integrated with the fire control) years ahead of the M60 series. It also was one of the most dependable systems on the vehicle. The gun was not a smooth bore, but rifled. Our master gunner equated the 152mm more akin to a direct fire howitzer in contrast to an M60s gun. We were inherently more accurate round to round.
There were other things I could mention, but as Talyn said, the article just skims the surface of the vehicle's performance and history and the author certainly can't call it a failure.
While I have the greatest respect for Dale Dye, there are a number of significant and misleading comments in his assessment.
1. The 152mm gun/launcher was most definitely not a smoothbore. It was rifled with a keyway cut at the 6 o'clock position that a key on the Shillelagh Missile ventral side would engage, preventing it's rotation. Conventional rounds were banded for the rifling apart from the Canister round. I will try to attach a fuzzy pic of the bore.
2. He refers to the conventional ammo as "caseless". This is incorrect, it was a combustible case (usually) that was meant to be consumed during firing, with any residual hot particles hopefully blown out with three shots of air from the Closed Breech Scavenger System (CBSS), a system that only just came on line at the last minute in 1969. Having been a "last resort" solution to the case residue problem there were several projects to make the gun adaptable to both a metal case (25 were prepared and fired & shown to be practical after a projected 21 month development period...this was time the program did not have). A glass particle "frangible" case was also explored. No combustion, but tiny bits that the CBSS would hopefully blow out.
3. The assessment about the track system is woefully wrong. Sheridan had one of the most reliable & robust track systems we ever employed....HOWEVER, the author was there for the early fielding when the tracks were being thrown largely due to the drive sprockets shearing off. Mechanics lacked torque wrenches to secure the sprockets and being too "loose", they put the bolts in shear without benefit of enough clamping force. I polled my fellow Sheridan crewmen & mechanics on a relevant page and was met with gales of laughter regarding torque wrenches. It seems they were also lacking in Germany as well. Our 2/11th ACR Sheridans rarely threw a track by '71-'72.
The lack of track support rollers was not an issue, being live track like most German & Russian tracked vehicles came to be.
4. The language about "cartridges meant to detonate in the breech". This is an erroneous statement...the combustible cased cartridges were indeed a fire hazard that could quickly consume the vehicle if ignited, but this is not a detonation. Sheridan DID have a "premature detonation" issue but that refers to the WARHEAD detonating prematurely. This was an issue that nearly killed the vehicle & probably should have. The XM409 HEAT round had a slew of "in tube" premature detonations and at least one just beyond the muzzle as late as 1969. As this was the only armor killer apart from the missile, this was a very serious matter. Combat Developments Command recommended that the Assistant Chief of Staff of the Army be notified in writing of the risk to crews should the vehicle be standardized.
By way of credentials, I was pre-trained on the M551 at the NCO Academy-Ft. Knox (to be a PL in the M551 school). Attended the 4-week Sheridan School at Knox, then served with them on my second campaign in VN. Subsequent to Vietnam, I was assigned to the Armor Board at Ft. Knox (1972-1973) & was on the Hughes LASER Rangefinder that would later be a component of the M551A1 years later.
1. The 152mm gun/launcher was most definitely not a smoothbore. It was rifled with a keyway cut at the 6 o'clock position that a key on the Shillelagh Missile ventral side would engage, preventing it's rotation. Conventional rounds were banded for the rifling apart from the Canister round. I will try to attach a fuzzy pic of the bore.
2. He refers to the conventional ammo as "caseless". This is incorrect, it was a combustible case (usually) that was meant to be consumed during firing, with any residual hot particles hopefully blown out with three shots of air from the Closed Breech Scavenger System (CBSS), a system that only just came on line at the last minute in 1969. Having been a "last resort" solution to the case residue problem there were several projects to make the gun adaptable to both a metal case (25 were prepared and fired & shown to be practical after a projected 21 month development period...this was time the program did not have). A glass particle "frangible" case was also explored. No combustion, but tiny bits that the CBSS would hopefully blow out.
3. The assessment about the track system is woefully wrong. Sheridan had one of the most reliable & robust track systems we ever employed....HOWEVER, the author was there for the early fielding when the tracks were being thrown largely due to the drive sprockets shearing off. Mechanics lacked torque wrenches to secure the sprockets and being too "loose", they put the bolts in shear without benefit of enough clamping force. I polled my fellow Sheridan crewmen & mechanics on a relevant page and was met with gales of laughter regarding torque wrenches. It seems they were also lacking in Germany as well. Our 2/11th ACR Sheridans rarely threw a track by '71-'72.
The lack of track support rollers was not an issue, being live track like most German & Russian tracked vehicles came to be.
4. The language about "cartridges meant to detonate in the breech". This is an erroneous statement...the combustible cased cartridges were indeed a fire hazard that could quickly consume the vehicle if ignited, but this is not a detonation. Sheridan DID have a "premature detonation" issue but that refers to the WARHEAD detonating prematurely. This was an issue that nearly killed the vehicle & probably should have. The XM409 HEAT round had a slew of "in tube" premature detonations and at least one just beyond the muzzle as late as 1969. As this was the only armor killer apart from the missile, this was a very serious matter. Combat Developments Command recommended that the Assistant Chief of Staff of the Army be notified in writing of the risk to crews should the vehicle be standardized.
By way of credentials, I was pre-trained on the M551 at the NCO Academy-Ft. Knox (to be a PL in the M551 school). Attended the 4-week Sheridan School at Knox, then served with them on my second campaign in VN. Subsequent to Vietnam, I was assigned to the Armor Board at Ft. Knox (1972-1973) & was on the Hughes LASER Rangefinder that would later be a component of the M551A1 years later.
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Thanks, I do have a certain amount of experience on select armor/cavalry/vietnam-cold war topics.Welcome to the SA Forum, Ascout. You sound like you know what you're talking about, and we welcome such people here!
The article's author has a great deal of influence in certain communities, which is why I commented, as it's worth of correction. His experience was apparently with the "three quarter" Cav, one of the two first units to receive the Sheridan (2/11th ACR as well) largely at the recommendation of Patton & Abrams who both wanted the vehicle "trialed" in combat with Cavalry units.
Neither the vehicle nor the ammo was ready, though the ~1,500 vehicles were already built and laying about at the Cleveland Tank Plant. Abrams heard of their existence and requested a contingent to be sent to VN. This was ill-advised and there were efforts to dissuade the USARV CG but he was having none of it. Quite a few people were embittered by the experience, including a former "Colonel of the Regiment" General Donn Starry, who had commanded the 11th Cav in Vietnam when it became so equipped.
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Cedric
Custom
Agree wholeheartedly. See my earlier comment. Also, by the mid-to late 70s the HEAT round was devastating to enemy armor. At Graf they put out "new" hard targets before we rolled in for gunnery, usually M-47s hulks. By the time our squadron rotated out, those targets were piles of metallic dust.
The LRF comments are gratifying to hear. My first Test Project at the Armor & Engineer Board (Ft. Knox) was the add-on Hughes LRF which began in March or April of 1972. Lengthy project on which I fired many rounds. Relatively trouble free & an improvement on the choke reticle if the target was oblique to the vehicle.
But it was not quite "years ahead of the M60 series"....in fact, the identical system equipped both the M60A1E2 & the production M60A2 even as we tested it on the M551 (it took years to be fielded, I don't know why).
As I was also on the M60A2 Initial Production Test the next year I was already familiar with the Hughes LRF, integral to the tank this time and not added on entirely outside the turret for lack of space.
Your gunner was commenting on the "trajectory of a football" 152mm round, which was not a hypervelocity gun like the M68.
Ultimately, the commitment to Shillelagh was due to limitations in the FCS of main guns of the time. At 2,000 meters, the probability of a first round hit for an average gunner on the M68 105mm was between 0.28 & 0.37 (ARCOVE report, "final report of the ad hoc committee for future tanks & other combat vehicles". Further development of conventional gun systems for armor was essentially abandoned. And look what rules the tank-tank battlespace today.
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Cedric
Custom
M60A2 yes, but three years into being on Sheridans, no M60A1s I encountered had LRFs, not even the M60A1 RISE passives. (IIRC)
Correct, no M60 or A1 had the LRF's. It was integral to the A2 and the later A3 came out several years after I ETS'd. I never experienced TTS, only the PVS-1 Starlight Scope in VN.
Cedric
Custom
We used TTS M60A3s at Ft. Knox to spot for the LRIP M3 CFVs night gunnery. Great sight and was actually more mature than the original M1 sights, though that changed as the M1 systems were upgraded.
We were still using the VSS-1 Xenon searchlights when i served.
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Always Ahead
Alpha
Always Ahead
Alpha
I had to join to put my two cents worth in when I saw the topic was Sheridans. I went to Ft. Knox for basic and 11D AIT. I stayed two extra weeks for R8 (Sheridan) training. Then they sent me to Ft. Hood in a recon platoon, Combat Support Company, 1/12th Cav Infantry Batillion, 1st Cav Div. (I never understood how they designated units there!) I was on a gun jeep playing agressor duty and meeting all kinds of guys coming back from VN. This was 1975. In 1977 I was sent to Fulda, 2nd Platoon, Alpha Troop, 1/11 ACR. Man, there were Sheridans all over the place. I was tall and skinny, so they never used me for a loader. I was always the driver. I'm here to tell you that downhill on the autobahn, a Sheridan would fly! But the steering was very very touchy.
I was never in combat in a Sheridan. And I'm sure I'd probably have a different attitude about them if I were. But know this: If the Russians ever decided to come through Fulda Gap, they would have known we were there!
It nearly killed me when we traded Sheridans for 60s. I felt like I was running in knee-deep mud.
But life in a Sheridan wasn't all peaches and cream. The damn heaters never worked. I got so tired of frozen C-Rations!
I'd love to I get in one today and drive it around. He'll, I'd like to have one sitting in my front yard!
Photo is Graf 1977 railhead. And Fulda motor pool (me on the right).
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I was never in combat in a Sheridan. And I'm sure I'd probably have a different attitude about them if I were. But know this: If the Russians ever decided to come through Fulda Gap, they would have known we were there!
It nearly killed me when we traded Sheridans for 60s. I felt like I was running in knee-deep mud.
But life in a Sheridan wasn't all peaches and cream. The damn heaters never worked. I got so tired of frozen C-Rations!
I'd love to I get in one today and drive it around. He'll, I'd like to have one sitting in my front yard!
Photo is Graf 1977 railhead. And Fulda motor pool (me on the right).
.
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Cedric
Custom
The reason for the Combat Arms Regimental numbering system for the First Cav is that they wanted to retain the unit designations from VN. Now, why they wanted to do that is simple, but violated Army unit lineage and unit organization rules. Short story: when the First Cav came back from VN they had an experiment with Triple Capability (Tricap) organization. Once that was over, the division basically returned to a standard armor division TOE. At that time, the division should have been re-designated the 4th Armored Division. The reason it stayed 1st Cav is because there was no pool of widely available veterans of the 4th to have an active association for scholarship funding, veterans programs and the like. Yup, a demographic and financial aspect drove the decision.
Always Ahead
Alpha
That's crazy, but typical.
Cedric
Custom
TTS was great. At the time it was more mature than the sight on the LRIP M1s. Eventually the sights on the M1s and succeeding models caught up in capability.
I just dodged the TRICAP Hood/Riley bullet. A clerk was flown out to our NDP in Tan Uyen District with a little folding desk. I asked another crew what was up with that and was told you advised him what you'd prefer for a CONUS assignment after Vietnam. I had done several training cycles at Ft. Knox and liked it (two of those related to the M551).
Nothing ventured, nothing gained so that's what I requested & it paid off. In fact, I knew of at least three guys who went from 2/11th ACR in Vietnam to the Armor & Engineer Board at Knox (tenant command of Aberdeen Proving Ground-Test & Eval Cmd.). Absolutely the best assignment an 11E could possibly have gotten & I got to do it for the next two years.
My very first test project was the Hughes LASER rangefinder for the M551 (and M60A2).
BTW, the 11th Cav as it fetched up in Germany later that year was simply a reflag of the 14th Cav, requested by two former Colonels of the Regiment who were now General Officers. There was no movement, just a reflagging.
The M551 never fired a shot in anger in Desert Storm/Shield. It's presence was more of a "fleet in being" that did not influence the fight. No Sheridan, anywhere, has ever fired upon a tank manned by an enemy. If it had, any kill would be the most reported and exalted tank battle since Michael Wittman.
Talyn
SAINT
Mostly correct
More on the M551.
M551 Sheridan Light Tank - The Army Historical Foundation
In World War II, the Army’s M3 (and later M5) Stuart light tanks, armed with a 37mm main gun, were immediately outclassed by heavier armed and armored German tanks in North Africa in 1942-43 and were relegated to reconnaissance roles.
armyhistory.org
The Sheridan Story - Part 3
Find out how one of the best known light tanks in the world - the M551 Sheridan, whose lineage can be traced back to the M41 Walker Bulldog - was developed and what teething problems the designers and users had to overcome.
How Tanks Played a Critical Role in the Persian Gulf War | HISTORY
Tanks— particularly the M1A1 Abrams—proved critical for U.S.‑led coalition forces in the Persian Gulf War.
www.history.com
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