Monday, January 22, 2018

WWII LVT(A) Amphibious Tank

In WWII, the military quickly realized that amphibious assaults would require efficient and effective means of getting men, machines, and supplies ashore.  More to the point, they quickly learned from bloody experience that they needed to get heavy firepower ashore in the initial wave and they needed to provide better protection for the assault troops than the open and unarmored Higgins boat, the iconic landing craft.  The solution to both needs, firepower and protection, was found in the Landing Vehicle Tracked (LVT) family of amphibious, armored vehicles.

I’d like to examine the armored firepower version, the LVT(A), of which there were several evolutionary variants.  The end result was the LVT(A)-4, essentially an amphibious light tank.  Take a look at the specifications.


LVT(A)-4 (1)

  • Armament – M8 turret with 75 mm M3 howitzer or Canadian Ronson flamethrower plus 1x 0.50 cal machine gun or 3x 0.30 cal machine guns
  • Armor – 6-38 mm
  • Weight – 20 tons
  • Speed – 20 mph land, 7.5 mph water
  • Range – 150 miles land, 75 miles water
  • Length – 7.95 m
  • Engine – gasoline radial, 250 hp; 12.5 hp/ton

Around 1890 LVT(A)-4’s were built during the war and continued in service until the mid-1950’s.  They were first used in combat at Saipan in June 1944.  Being in the initial assault wave and then used at the front line of combat once ashore, the LVT(A)-4’s often experienced high loss rates.


LVT(A)-4


A few things jump out when looking at this vehicle.  First, the LVT has essentially the same specifications as today’s Marine Corps Amphibious Assault Vehicle (AAV).  That we have been unable to produce a significantly better vehicle in seventy some years is depressing and disturbing. 

For comparison, here are some specs on the AAV.


AAV (formerly LVTP-7)

  • Armament – turret with Mk19 40 mm grenade launcher and M2 0.50 cal (12.7 mm) machine gun
  • Armor – 45 mm
  • Weight – 29 tons
  • Speed – 20 mph land, 8.2 mph water
  • Range – 300 miles land, 20 miles water
  • Length – 7.94 m
  • Engine – diesel, 400 hp; 13.8 hp/ton

Now, before anyone starts pounding out replies disputing some specification, just relax.  The exact specs are all over the map depending on exactly which version of the AAV we’re talking about and which upgrades it’s had.  The point of this comparison is not to discuss exact specs but to note the lack of significant improvement since WWII.

The most notable aspect of the comparison lies in the armament.  The LVT(A) had a heavy 75 mm howitzer whereas the AAV has only machine guns and grenade launchers.  To be fair, today’s AAV is not intended as a “tank” whereas that was exactly the purpose of the LVT(A).  The AAV is simply an armored personnel carrier and is not meant to provide heavy firepower.


LVT(A)-4 at Okinawa


While today’s military continues to flounder around with the dilemma of firepower in the initial assault wave the WWII military solved the problem with a light amphibious assault tank.  Today, China has developed light amphibious assault tanks and the US military views that as cutting edge and a controversial concept.  Hey, it’s just reinventing the WWII wheel.

We also need to keep the role of a light amphibious tank firmly in mind.  It's role is not to stand toe-to-toe with main battle tanks - no light tank can prevail in such a match up.  The role of the amphibious light tank is to provide heavy infantry support with suppressing fire and to reduce enemy strongholds, fortifications, and emplacements.  Thus, an amphibious light tank does not need to be a water-going Abrams - though figuring how to get an Abrams ashore in the initial assault wave would be great!



LVT(A)-4 Providing Infantry Support


We lack any kind of significant firepower in the initial assault wave and the Navy has doctrinally stated that they will not risk ships close enough to shore to be able to use even the small 5” guns.  Airpower, against a peer, will be only sporadically available and, in any event, is unable to provide the sheer volume of sustained heavy firepower needed to support an assault. 

The only viable solution is to provide heavy firepower in the assault wave and the only way to do that is with a tank of some sort.  We would do well to consider the lesson of the WWII LVT(A)-4 as we continue to ponder our amphibious assault doctrine and operations.



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(1)World War II Database,


29 comments:

  1. If the Marines do get a light amphibious tank I hope they don't make the mistake of the Expeditionary Fighting Vehicle and try to make a do everything vehicle.

    That is trying to stuff 20 Marines plus a gun plus high speed.

    You notice with the LVT(A)-4 (1) that it carried no infantry and they took the standard infantry vehicle and put a gun on it using the space and weight formally used by the infantry.

    In my opinion the Expeditionary Fighting Vehicle would have had a greater chance of success if they had two vehicles using the same base vehicle one to carry Marines and the other to be a light tank.

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    1. "don't make the mistake of the Expeditionary Fighting Vehicle and try to make a do everything vehicle."

      Quite right!

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  2. A low-velocity 120mm or 105mm gun firing HESH and therombaric shells could be interesting. Even a turrted 120mm mortar might work. The specs for the AMOS and NEMO 120mm mortar systems are roughly comparable to the M116 75mm pack howitzer.

    While not amphibious, the British experimented with the "demolition tank" concept in WWII and the Cold War. The Churchill III/IV were armed with 290mm spigot mortars and were used in Normandy to clear beach obstacles and fortifications. The Churchill VII and Centurion AVRE 165 were refinements on this concept and were armed with 165mm demolition guns and equipped with dozer blades and mine-clearing equipment.

    An amphibious "demolition tank" could provide heavy HE firepower in the initial assault, clear landing zones for LCACs and LCUs carrying proper MBTs, and provide "mortar" and assault-gun support in the latter phases of an amphibious assault. Limiting the vehicle to "engineering" duties may help avoid the kind of feature-creep that would likely happen if this "tank" were expected to engage enemy armor.

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    1. The US also introduced a similar "demolition tank" in the form of the M728 CEV (based on the M60) that was armed with the essentially the same 165mm gun as the Centurion AVRE 165.

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    2. The challenge is not designing a tank, of whatever variety, but in figuring out how to get it ashore with the initial assault wave. Are you suggesting putting the various weapons/turrets you described on AAVs or did you have something else in mind?

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    3. My point is that the modern analogue of the LVT(A)-4 is an AAV armed with a turreted, low-velocity gun or mortar. History suggest that this type of armament is sufficient to provide infantry support and is in some ways better than a high-velocity gun in this role (LV shells have a greater HE mass ratio). In the past, these types of vehicles have also incorporated battlefield engineering hardware. Our experiences in Iraq, however, show that the AAV armor is marginal at best against RPGs and totally inadequate against ATGMs. While an APS might help, I suspect that this will bet true of any amphibious vehicle.

      If dozer blades and mine-clearing equipment could be made compatible with an amphibious vehicle, I think we'd have a very useful amphibious demolition tank that could clear the beach for the arrival of proper MBTs and IFVs on LCACs and LCUs. After the well armed and armored MBTs and IFVs carry the fighter further inland, the amphibious demolition tanks would support the leg infantry with direct and indirect fires.

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    4. "amphibious demolition tank that could clear the beach for the arrival of proper MBTs and IFVs on LCACs and LCUs."

      The question becomes, can we secure a beach with just infantry and an AAV/turret vehicle? Can such a light force, with no naval gun support and only sporadic air support secure a beach against a peer defender? I suspect not. If not, then we can't get follow-on heavier forces ashore since the LCAC and LCU are not considered survivable in a contested environment.

      Remember that in WWII, we realized that we needed an LVT(A) EVEN WITH HEAVY NAVAL GUNFIRE SUPPORT! Today, we have no naval gun support and I don't think some AAV/turret vehicles can make the difference alone.

      Elimination of naval gun support and the relocation of the assault force 25-50+ miles offshore has made the concept of an amphibious assault extremely questionable.

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    5. @ Caliber-Curious

      "If dozer blades and mine-clearing equipment could be made compatible with an amphibious vehicle, I think we'd have a very useful amphibious demolition tank... "

      LVTE-1 (Landing Vehicle, Tracked, Engineer) - the corps built 41 starting in 1956. And it had two rocket propelled mine clearing charges similar to MCLIC.

      AKAIK the Corps toyed with the idea of a engineer variant of the LVTP7, but these were not produced in any numbers.

      GAB

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  3. Good follow-on from you previous discussion on the surface connector conundrum. I recall from my previous time wrestling with these issues finding an article and some proposed specs of a submersible/semi-submersible amphibious transport that the USN was pondering during WW2 that could be used to deliver main battle tanks amphibiously ashore. It was essentially a cross between a submarine and an LST. My memory is hazy, but the proposed (and humongous) craft would submerge as it approached a hostile shore to avoid enemy targeting and shore-based fires, surfacing only to disembark infantry, tanks, etc. Pretty crazy concept but the fact that the USN/USMC was thinking about this over 70 years ago is fascinating. Despite the findings, there was no significant interest in looking at this concept in recent years due to the usual concerns (costs, acquisition, underwater mines, the forcible entry debate, yada yada yada). But as you allude to, there really hasn't been any other outside the norm thinking with regards to surface connectors, amphib ships, amphib tanks, light tanks, etc in the past 70 years that has moved the needle. None of the USN/USMC equip modernization really does (MV22, F35, amphibs, re-incarnated LCU/LCACs-- let alone AAAV/EFV and ACV, nor the doctrinal evolutions of EF-21 (distributed ops, company landing teams, use of CLTs to seize land-based F35 operating bases, etc). Amphib tanks or light tanks or even a future main battle tank are not even in the discussion stages. The talk of multi-domain battle still don't illuminate viable concepts of ops to solve the amphibious forcible entry dilemma either. Hard problem to crack with all the constraints indeed!

    Charlie

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    1. Wow, never heard of a sub LST! Would be interesting to find some specs and drawings of that!

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    2. NICO, I'm hurt! What do you mean you've never heard of a submersible LST?! I presented a drawing of one on this blog! See, Submersible LST

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    3. I used to have a scanned picture of this USN LST Sub. I believe it was from an old Marine Corps Gazette article or Proceedings, can't remember. Will have to look around.

      Charlie

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    4. My bad! I don't think I was a reader back then in 2013!

      Interesting idea, my guess one big problem would be making sure you don't get stuck but isn't that a problem any ship hitting the beach faces?

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    5. "I don't think I was a reader back then in 2013!"

      *gasp* Are you saying you haven't read the archives completely through?! The wisdom contained in them is unmeasurable. Most people report that their personal IQ increases by 30 points after reading the archives and that they get invited to more parties because they're more interesting and knowledgeable about the world affairs. I guess I know what you'll be doing the rest of the week!

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    6. I get the impression that the LST was a one-time, one-way trip during an assault. They would float them back off the beach whenever they could but they didn't go back for another load during the course of a given assault. Thus, the issue of refloating was not a pressing one! If necessary, it could wait until things quieted down and they had more time to work on it. On the other hand, I can't recall many instances of LST's getting stuck on the beach for any significant amount of time. It would be interesting to find some information on refloating. I can't recall ever reading anything about it. Let me know if you ever come across any information.

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    7. LSTs figured prominently in both WWII and Korean war doctrine and planning, at one point LST production in anticipation of the Normandy landings became a FDR-Churchill level issue.

      LSTs were generally used once in a landing due to the tide considerations.

      The key value of the LST was its ability to land reinforced company sized mechanized elements (the battalion slice) immediately following the assault waves and in good order. This is critical as the assault waves generally were disordered and frequently shot-up after landing, which made them ineffective to push the force onto its objectives. Four or five LSTs could land a reinforced tank battalion or mechanized infantry battalion with attached SP artillery relatively quickly so they could drive on to objective. The LST was criticized as slow and expensive relative to its cargo capacity, but no other ship or combination of landing craft could deliver a force with the same operational speed as the LST.

      LSTs were far too valuable to be used in the initial assault, LCTs and DD tanks) were used to land armor assigned to the assault. Interestingly, LCTs were often loaded onto LSTS and launched by ballasting the LST (tipping to one side) and the LCT was unceremoniously slid into the water! MK 6 and MK 7 LCTs could land a medium tank platoon. LSTs also were used to ferry LVTAs to their launch point during an assault, and also as hospitals taking wounded of the beach, etc..

      The traditional LST became untenable due to the fast post-war submarine: the hydrodynamics needed for beaching, conflict heavily with need to maintain twenty+ knot speeds needed to evade submarines. The USN looked at catamarans and other ideas even back in the 1960s, but was unwilling to take the risk on non-traditional hull forms.

      My opinion is that the USN needs to revisit the LST concept, after it solves the problem of in-stride breaching sea mines. The “why” is simple: while we are unlikely to see the levels of fortifications from past conflicts, artillery, particularly massed MRL launchers and PGMs, demand that we land our armor and get off the beach ASAP!

      A 21st century LST should be able to carry a reinforced tank/mech infantry company, 30-knot+ speed capable, possess a robust CIWS, and have a credible G-RAM system(s).

      GAB

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    8. A new LST is all well and good, but against massed tube and rocket artillery anything that can't get off the beach in short order may be in significant peril. Do we really want a 30+ knot LST sitting on the beach until it can winch itself off and/or the the tide comes back in?

      The real hero of any successful landing is going to be the INLS system. I'd like to see the Navy experiment with assault INLS modules. INLS is little more than various modules (essentially small, powered barges) that can be propelled by warping tugs. INLS causeway ferries are already in use. An assault ferry would have a streamlined bow/ramp module and perhaps gunwales and more powerful tug(s). I'd also like to see screw piles incorporated into the assault modules so that they could beach themselves and quickly secure themselves against the surf. The tug would detach and go about its duties while follow-on LSTs and HSTS offload onto the INLS causeway, which might be extended by attaching additional modules, instead of having to beach themselves. The INLS modules are cheap and expendable in the event that they take damage.

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    9. "A new LST is all well and good, but against massed tube and rocket artillery anything that can't get off the beach in short order may be in significant peril."

      We may be misunderstanding assault doctrine a bit, here. LSTs would not come ashore until the threat was reduced to an acceptable level. Thus, "getting off the beach in short order" and "significant peril" are not really concerns. That's not my opinion, that's doctrine.

      Further, LSTs are cheap in the scheme of naval construction - or, at least, they should be. The LSTs of WWII were cheap and were intended only for the duration of the war. Only if the modern Navy decided to build one would they be expensive enough to care if one were destroyed on the beach. An LST should be a cheap, barely capable, throw-away vessel. Even the Newport class LST began to violate these principles by being expensive, complicated, and permanent.

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    10. @ Caliber-Curious

      There are other technologies applicable to LSTs that avoid the issues you raise.

      INLS takes the better part of a week to construct under optimum conditions, and more than a week to build if the seas/weather are uncooperative. And even when built, the throughput is woefully inadequate. Again, there are better solutions available in the commercial world.

      GAB

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    11. "Again, there are better solutions available in the commercial world."

      Sounds like a post waiting for some enterprising person to write!

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    12. @GAB

      "INLS takes the better part of a week to construct under optimum conditions, and more than a week to build if the seas/weather are uncooperative. And even when built, the throughput is woefully inadequate."

      I think you're conflating ELCAS with INLS. The various INLS configurations take hours not days to construct (at most, 36 hours to construct the RRDF) because they float and are not supported by piles.

      What I'm talking about are basically INLS-based spud barges that would come right behind the amphibious vehicles during the assault to land MBTs and other heavy equipment. Rather than unbeach themselves, the barges would form the beginnings of floating or jack-up piers. The oft-cited ThinkDefense port-opening piece discusses these concepts.

      https://www.thinkdefence.co.uk/joint-port-opening-capability-proposal/

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    13. @ Caliber-Curious

      Yes, I jumped right into the elevated causeway systems; but INLS is not the solution to amphibious assault.

      Causeway/warping tugs have great utility, but no barge is going to provide the sea keeping, speed, or other attributes needed for a 21st century, peer competitor assault.

      The TD article is a great source.

      GAB

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  4. Be careful of patent infringement, CNO.

    https://www.google.com/patents/US2627832

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  5. Just some random thoughts:

    - The gun: a 75 mm howitzer! Quite interesting because at that time there were 75 mm high velocity guns available. I’m thinking on the Sherman tank gun. Instead, a howitzer was chosen. Caliber-curious made a point regarding low velocity guns firing HESH or thermobaric rounds.

    - The British have a light tank that fires a 76 mm low velocity HESH round. And they actually used it on amphibious operations! The CVR-T Fv-101 Scorpion. Blogger “Thinkdefence” has written a lot about it. https://www.thinkdefence.co.uk/british-army-medium-weight-capability/the-seventies/

    - How to get ashore with it? Just embarking on a LCU. http://fotos.subefotos.com/f4af28fc07ea733d0a86f84ec6d4f7abo.jpg

    https://2.bp.blogspot.com/-yvYPcU3oZ84/Vv6sQeOw4HI/AAAAAAAB9X8/DlmcKt2Om5s7RY5ENyk-QjKQ5BurmW2Iw/s1600/11998631_964987100229977_860024182_n.jpg

    - You don´t want to use a landing craft? The FV-101 turret has been mounted on a M-113 chassis: http://3.bp.blogspot.com/-h6adKeDBcRE/Us3OgCG_TkI/AAAAAAAA5_U/vseFOOC1MY4/s1600/FSV10.jpg

    - Finally, a M-113, with some add-ons can actually swim:
    https://www.aris-spa.it/wp-content/uploads/2015/09/arisgator6-f.jpg

    So: Fv-101 turret + M-113 + buoyancy add-ons = amphibious light tank.

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    1. The problem with getting a tank ashore is that the obvious connectors, the LCAC and LCU, are doctrinally restricted from the initial assault wave as they are considered non-survivable.

      The problem with buoyancy add-ons is that most/all are not capable of swimming more than a very short distance. The Marines/Navy are doctrinally committed to 25-50+ mile standoff. There's no way any buoyancy add-on vehicle could make that trip.

      So, we're left with the problem of how to get the tank ashore! Creating a tank is easy. Getting it ashore is the challenge.

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    2. "75 mm howitzer! Quite interesting because at that time there were 75 mm high velocity guns available."

      I assume the howitzer was chosen because the intended purpose was anti-infantry and fortificaton/emplacement reduction rather than anti-tank which was the purpose of the high velocity gun. I noted this in the post with the reminder about keeping the role of the amphibious tank in mind. The temptation by any military designer will be to try to make an amphibious tank a do-everything, main battle tank and that will make it unaffordable and non-amphibious.

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    3. The 75mm howitzer, really the complete turret from the M8, became available as artillery forces were called upon to deliver increased weight of fire.

      75mm guns were once standard for infantry support, but artillery moved from 75mm to 105mm, and late in WWII even the 155mm (150mm and 152mm in German and Russian service respectively) played a more dominant role.

      GAB

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  6. That's a similar concept

    2S25 Sprut-SD self-propelled tank destroyer

    https://www.youtube.com/watch?v=-CzBz_bPe5M

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  7. " Submersible LST "

    BTW the soviets had a freakin idea of a whole nuclear powered landing submarine ! It was so big it could carry tanks, unfortunately it never went past a model mock up :D

    https://www.liveinternet.ru/users/panzir56/post354941234/?aid_refresh=yes

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