Problem
Amphibious assaults?
A moot concept since we have no landing craft.
Wait, what? Of course
we have landing craft! We have the LCAC,
LCU, and LCM. Well, yes, we have those
craft but none of them are initial wave assault craft. They’re follow on craft for sustainment after
the assault site has been secured.
The only initial wave landing craft we have is the Marine’s
AAV/ACV which is not really a landing craft in the traditional sense of a small
boat that can delivery troops to the beach and return to the host ship to get
more troops for subsequent waves. The
AAV/ACV is a one-way, amphibious, light armored personnel carrier (APC).
Let’s do the math. An
AAV/ACV can carry around 15 combat equipped troops and a MEU (we’ll discuss a
MEU but this scales up to whatever size and, yes, we recognize that a MEU, on
its own, is not capable of conducting an opposed landing) has around a dozen
AAV/ACV so that represents a landing capacity of around 180 troops that can be
delivered to the beach. The remainder of
the MEU’s 2200 troops have to find some other way to get ashore. That’s an initial assault capacity of around
8% of the MEU.
A MEU has around 16 transport helos/MV-22s, each of which
can carry 15-20 combat loaded troops but, again, these are not initial assault
assets. Helos are not survivable over a
battlefield. They’re follow on
transports.
Are 180 troops per MEU really enough to conduct an opposed
landing? Of course not! Thus, we have a problem.
Solution
So, what’s the solution?
I’ve heard many people recommend foreign “landing craft” such as the
CB90, Jehu (Finnish), Raptor (Russian), etc be used as landing craft. Claimed benefits include a [very small]
degree of stealth, speed, armament, and the ability to fit six or so craft in
the well deck of an amphibious ship.
 |
| CB90 |
 |
Jehu - Note the narrow, restricted exit ramp and imagine
fifteen or so combat laden troops trying to rapidly
debark, one at a time, under fire. |
Analysis
Let’s take a closer, analytical look at this type of boat in
the landing craft role.
Troop Capacity – This size boat claims to be able to
carry 15-20 or so troops, likely less when the troops are combat equipped. Let’s be generous and use a figure of
20. For 6 boats, that’s 120 troops per
assault wave. Is that an assault or a
school board meeting? By comparison, a
WWII attack transport carried around 24 landing craft, each of which could
carry around 30 troops for a wave of 720 troops.
Cargo Capacity – None. These types of craft have no cargo
capacity. That’s all there is to say
about that. The troops would land with
whatever they can carry on their person.
Debarkation – One of the constant characteristics
across these types of boats are the requirement for the troops to debark via
narrow passageways, single file, slowly.
While some claim to have restricted, emergency egress, it is, again, an
exceedingly slow and cumbersome process.
Under fire, these boats are death traps for the troops. Arguably, the most important characteristic
of an effective landing craft is the ability to rapidly discharge the troops while under fire. The WWII Higgins boat allowed the troops to
egress, line abreast, several at a time, simultaneously, across the bow
ramp. In an emergency, dozens of troops
could simultaneously egress over the open sides.
Cost - This
type of craft costs several million dollars apiece, or more, which is way too
expensive for a niche craft that is likely to suffer high rates of attrition
and needs to be procured in large numbers.
Conclusion
It is patently clear that these types of craft are not
suitable for amphibious assaults. They
are suited (and this may even be overly optimistic) for the kind of tiny raid
operations or patrol duties they were designed for. We need to stop looking for foreign landing
craft because there are none that are suited for the purpose. If we want a landing craft, we need to go
back to the drawing board and design a dirt-simple, modern, Higgins boat and be
done with it.
Of course, such a landing craft would require a radically
re-designed amphibious ship to make use of it … you know, something like a WWII
Attack Transport (APA) but that’s a separate, though intimately related, topic.
Given that ComNavOps sees very little strategic need for
future amphibious assaults and given that the Marines have publicly stated that
they are out of the assault business, this entire discussion is probably moot
but at least we now know what won’t work and can stop bringing up these types
of boats.
The Jehu has 24 troop seats and 5 seats on the crew level. If you crewed it with just 3 you could move 2 squads per boat. The Marines have trained with the Finns in these boats and have brought the boat into the well deck. I agree none of these types cut it.
ReplyDeleteWe do need something that can land infantry, but we will always need something that can really support logistics and rolling vehicles ashore. We also need an enhanced basic defense. Most landing craft and assault boats can do a CROWS mount with M2, but we really need the ability to carry something with high elevation and air burst for drones and RAM. The 30 x 113mm RWS with coax 7.62 and ability to mount Stinger and Javelin is the level needed here. I would also say that when moving infantry you will need some bolt in armor protection and it seems that class III is the standard, take it or leave it.
The real trick is do you care more about maneuvering like an assault boat or more like a landing craft. The good news is landing craft seem to be speeding up. The Army's MSVL and France's EDA-S both use trimaran/tri-bow configurations with MSVL making 30 knots unloaded and 21 loaded on an aluminum hull. The French one which would fit 2 in an LCAC spot make 18knots laden on a steel hull. What we ideally need would fit 9 in a 2 LCAC well deck and have carrying capacity along the lines of a C-130 such it could bring a reinforced platoon ashore or the majority of Marine combat vehicles currently being planned or in development. Spotting 6 is easy, 9 is hard unless you want slow like an LCM-6. I keep working on a design. Size wise Kewatec 1920/Finnish Uto class shows what can be done with a basic landing craft although it is not a ro-ro and has crew berthing which I would not include on a craft this small that really will only function as a ship to shore connector.
"Jehu has 24 troop seats"
DeleteAlong with wondering what the true capacity is when the troops are fully combat loaded, the far more important question is how quickly can they debark? The answer is, nowhere near fast enough when under fire.
"support logistics and rolling vehicles ashore"
That's not an initial wave function and we do have such vessels: LCAC, LCU, LCM. Of course, the now extinct LST would also serve well in this role.
"We also need an enhanced basic defense."
Against what??? Why does everyone have the compulsion to turn every asset into an uber-machine? What does a landing craft need to defend against? WWII landing craft had a machine gun, at most, in case some lunatic enemy came running down the beach at them, I guess, or maybe to offer a squirt of suppressing fire as the troops unloaded.
The Burkes and Constellations will handle air defense. We don't need to try to turn landing craft into Aegis air defense platforms.
"EDA-S"
That's not a landing craft, it's an ocean-going transport with a claimed range of 300 miles or so. It's also way too big to be used as a troop landing craft. I haven't seen a spec but it looks like you could cram in a hundred troops or so and that's way too much risk in one platform. The Higgins boat was a nice balance of dispersal of risk and concentration of troops for efficient delivery.
What I've read indicates that around four could fit in a well deck. Again, that's woefully insufficient for an assault and leaves the invading force hugely vulnerable to attrition. Losing just a single one would cut the assault capacity by 25%!!!! This kind of craft could be marginally useful as a follow on, sustainment vessel after the beach has been secured but, even then, there are other vessels that would be far superior in terms of delivery rate.
You're wandering off into technology land and not keeping the objective in mind. The objective is low risk, troop delivery. Nothing more. No anti-air, no ocean going, no advanced weaponry, to large cost and small numbers, no complex design that's hard to build. You could probably build a hundred Higgins boats in the time it takes to build an EDA-S.
Why is it so hard for the military and military observers to keep things simple? Why do we instantly want to add everything we can think of to every platform?
If you think Aegis ships are going to handle RAM and UAVs I'm not sure I want to be on whatever boat you are comfortable getting a ride on. I am basically suggesting the next size up in armament from what all these boats mount when needed already. My point on the EDA-S and MSVL is there might be some value in a smaller trimaran lander.
DeleteIn lieu of armament, it might be better to just plan one boat bringing in your C-UAS defense with MADIS/L-MADIS to provide cover for the other boats. That would probably be the efficient/cost effective means.
"If you think Aegis ships are going to handle RAM and UAVs"
DeleteThere currently is no anti-rocket/artillery/RAM in the US inventory except the land based Centurion C-RAM so no vessel is capable of that. Interestingly, the Aegis ships are technologically capable of conducting counter-battery fire but they lack the software to implement it. So, if we added the software, all our ships could conduct counter-battery with their 5" guns.
As far as UAVs, of course Aegis ships can handle that. They're doing it every day against the Houthis. I have no idea why you think an Aegis ship can't handle UAVs.
"I am basically suggesting the next size up in armament"
What you're suggesting is the next level up in cost and complexity which means decreased production and numbers. That's the opposite of what you want in a landing craft that is a niche asset and which will suffer high attrition.
"In lieu of armament, it might be better to just plan one boat bringing in your C-UAS defense with MADIS/L-MADIS to provide cover for the other boats."
I get the impression that you're trying to create a very small raid type assault rather than a full amphibious assault. Small boats with small weapons are not what's needed. What's needed is 16" battleships and 8" cruisers backed by lots of 5" destroyers. THAT'S your defense. Massive area bombardment to destroy and suppress. No enemy is going to be leisurely lobbing mortars or artillery or directing UAVs with large caliber shells raining down. Again, with minor software mods we have counter-UAV fire in the form of instantaneous naval gun fire on the source of UAV control signals.
I design for the workd we live in. You want to bring back battleships to blow a reef that could be addressed any number of ways and want to bring 330 sailors and a 2.4 billion dollar aa platform in range of shore fire just to use the 50 year old design of a lightweight 5 inch gun.
Delete"I design for the workd we live in."
DeleteIf that's the case, then there is no discussion because no sane commander would attempt an opposed landing with the limited assets and resources we have available!
Recognizing the impossibility of a landing today, we then move on to discussing what we need to allow us to contemplate a landing and that brings us to things like large caliber naval gun support, large scale mine clearance, landing craft, counter-battery fires, and so much more.
Feel free to join in the discussion or remain silent if you have nothing worthwhile to contribute. Thanks. Have a good day!
If we started with a Higgins boat, what modifications would need to be made to get it up to meet the needs of a modern landing craft?
ReplyDeleteLutefisk
"what modifications"
DeleteArguably, none!
Deliver a riskable number of troops a short distance from ship to shore and unload them as quickly as possible and do it with an asset that is dirt cheap and can be built quickly and in large numbers. We kind of had this figured out in WWII.
Can you think of anything a Higgins boat should have been able to do that it couldn't? If not, there's no need to try to 'improve' it. As the anti-engineers say, if it ain't broke, don't fix it.
"Can you think of anything a Higgins boat should have been able to do that it couldn't?"
DeleteWell, I do seem to recall reading that they sometimes got hung up on offshore reefs when attacking islands in the Pacific, forcing the troops to wade in over fairly long distances. Not sure how to fix that by modifying the Higgins boat. Maybe the AAV (with the tracks) could overcome it. Or perhaps a change in tactics?
Identify the reefs pre-assault and blow them up with 16" shells from the battleships ... which we don't have.
DeleteAvoid the reefs or blow assault lanes through them. No need to try to invent a combination landing craft / tracked transport. The simplest solution is always the best!
(Don McCollor) Nagele, ComNavOps, I think the landing was Tarawa. It has unpredictable dodging tides. When the landings occurred, the reef was awash where the LCVPs hung up and much of the lagoon was shallow enough to wade (there were reef passages, but protected by Japanese shore batteries). Four days later, the tide was lapping at the top of the seawall. A marine noted that it did not matter much. If they had landed then, they would not have had the cover of the seawall for protection.
DeleteWe can have a faster, more maneuverable boat, with better payload and less draft than a Higgins boat using existing tech in the commercial industry. We can also have a ramp that can interface with a pier and not just the beach.
DeleteA modern Higgins boat might need to be slightly wider as a Humvee is wider than a Jeep.
DeleteI would expect that airburst rounds might be more prevalent than during WW2. Possibly a kevlar cover over the infantry to protect from shrapnel.
My concern however would be that the weight would screw up the stability of the boat.
The threat from kamikaze drones is new. Possibly a couple of guys in the back with hand-held drone jammers and another guy with a GAU-19 to shoot them down.
Lutefisk
"We can have a faster, more maneuverable boat, with better payload and less draft than a Higgins boat using existing tech in the commercial industry."
DeleteOf course we can! We can give it 16" guns, a flight deck, a well deck, torpedo tubes, and the ability to submerge. Of course, it will cost a trillion dollars and we could only build one.
The issue is not whether can load technology, weapons, and sensors on a landing craft. The issue is whether we need to and the answer is, emphatically, NO! A landing craft's job is to transport troops a few miles from ship to shore and then RAPIDLY unload them. A landing craft doesn't need weapons, sensors, or anything else (maybe some frontal armor against small arms fire?) to accomplish that task. Everything that's added that isn't needed just adds cost and cuts production and numbers. I don't know why so many people have such a hard time with grasping the concept that you control costs by building the SIMPLEST equipment that can meet the requirements rather than the most complex equipment possible. K.I.S.S.
We had this figured out in WWII.
"Possibly a couple of guys in the back with hand-held drone jammers and another guy with a GAU-19 "
DeleteNO, NO, NO, NO, NO! It is not the job of the landing craft to be an air defense asset or even to protect itself. It is the job of the escort ships with massive power output jammers to disrupt UAV control signals. It is the job of the escorts with long range guns and missiles of all sizes to SCREEN against UAVs. That's why we have escorts! Let them do their jobs. Don't load capabilities on a landing craft. The landing craft's ONLY job is to drive the troops to shore and RAPIDLY unload them. Someone else protects the landing site and landing craft.
Let the escorts do their job!
We had this figured out in WWII. Why are we trying to make it more complicated and costly?
"A modern Higgins boat might need to be slightly wider as a Humvee"
DeleteA Higgins boat is intended to transport troops, not vehicles. Vehicles, especially glorified jeeps, are of no use during the initial phase of an assault. By the time jeeps can be useful, we can bring vehicles ashore with LCU/LCAC/LCM and don't need a Higgins boat.
Again, let's not try to make a Higgins boat more than it is.
Now, if we could produce a landing craft that could transport a single tank, that might be of use in the initial assault.
They're overly large, but the Army's new aluminum landing craft is in production now here in Vancouver...
DeleteUtilizing an unchanged Higgins boat design (dimensions), an LPD could likely carry enough (~20?) in the well deck to get most of its roughly 700 troops ashore in a first wave. An LHD could carry roughly 50% more, getting it's 1600+ troops ashore in just over two waves.
ReplyDeleteNow of course, that ignores breakdowns, losses, etc, and you might also want other options in your well deck, like a mix with ACV, or LCAC, changing the well deck calculus. But, simple changes to allow them to be stacked on deck (boats are much more useful than Osprey in a real assault, so losing flught deck space isnt a real loss), and addition of a crane or three, to offload them, makes them a choice that reenables the MC to get ashore, and in bulk...
LHD can carry 40 AAV in the well and LSD 15 so there would probably be about 21 Higgins in a LHD and 12 in an LSD?
DeleteAdmittedly I went off of raw dimensions, although I did round down.
DeleteNot pushing the envelope on width, and removing a lengthwise "row" from each, I end up with LHD: 24 and LPD, 16.
Hang a second layer of Higgins boats from the underside of the deck above on cables and pulleys and double your numbers. First wave goes out, drop the boats for the second wave.
DeleteSure. Although a 9 tons for the original version, that could be tricky. I'd suggested just stacking some up on the flight deck- loss of a spot or two would be totally worth having another half-dozen/dozen.
DeleteThere is no reason why we can’t ditch LCACs and replace them with LCUs so we can land 2 companies of infantry. ACVs can land another company. Provide some indirect fire support/suppression to enable LCUs and ACVs like WW2 Higgins craft and LVTs.
ReplyDeleteLCACs need to be put on ships dedicated HADR because they have an ability to beach many places but are for completely permissive environments. They also break too often to be dependable for combat and go much slower than advertised to prevent breaking.
With an all LCU and ACV force, we just have to provide the fire support to conduct amphibious operations.
HIMARS pods on amphibs can provide long range precision but we need volume fires. For this, we need a new type of ship with cannons / guns.
In the meantime, we can probably place another company on a LCS and launch it ashore with RHIBs. The LCS helicopter deck can house 4 AMOS 120mm mortars to provide volume fire support against lower level threats until we get a dedicated design because we are not using LCS ships anyway.
You're not suggesting the LCU as an initial assault transport, are you? The LCU, like the LCAC, LST, or LCM is a follow on, sustainment vessel. It's large size (160 ft vs a 36 ft Higgins) and slow speed makes it far too vulnerable a target to risk in initial waves and the concentration of troops/vehicles makes it far to costly to lose.
DeleteRHIBs as an assault force?? I can't see that being viable. Navy doctrine calls for assaults from 25-50 miles offshore. That rules out RHIBs. Even at horizon distance, RHIBs seem unworkable
Just to offer some perspective, a company (say, 100 soldiers) could be transported in just three Higgins boats but you're suggesting using an entire LCS to land 100 soldiers instead of just three Higgins boats?
Yes, ditch the LCACs. They are too expensive, burn too much fuel, break down a lot, and most importantly, they have zero armor. An LCU is bullet proof and can carry lots more. Send LCUs and new LST to shore since they can take drone hits, ATGM hits, and gun hits and keep on chugging to shore. Small, slow craft will get shot up like ducks in a shooting gallery.
Deletehttps://www.g2mil.com/Landing%20Ship%20Assault.htm
Let's get serious about distance, speed, and fatigue.
Delete- Helos get there fast and the Marines are set up for a 110nm combat radius with CH-53, UH-1/AH-1. V-22 can go further and faster, but the only thing that can go with it is whatever is riding on the KC-130.
-SSC, the LCAC replacement should hopefully have better maintenance as the design has been simplified. I won't bet on that, but its stated mission radius is 25nm. That is the assault benchmark, ships will often be over the horizon. This is why the Expeditionary Fighting Vehicle was designed for speed. Get there before your Marines are cramped, up puking, and sick. AAV can't get that done and neither can ACV or the new recon vehicle. They might have value dealing with rivers, estuaries, etc, but not a beach assault. We need a boat that can bring Marines ashore and the means to move them inland. It needs to carry a KC-130J load, 25nm at 25 knots for ship to shore in about an hour. It needs to worry about mines, RAM, and C-UAS either organically or via the embarked Marines capability. Of course, then how does it defend itself on the way back to the ship?
Big Army wants to have a Future Vertical Lift Heavy that's essentially a VTOL with the cargo bay of a C-130. Something like that might be the only way to make a beach assault viable, in the sense that it'll drop either a company of troops or an APC onto the beach. Of course, it's also a large and pretty obvious target, as all transports are...
Delete"Helos get there fast"
DeleteWhich, over a battlefield, means they die fast.
"It needs to carry a KC-130J load"
No, quite the opposite. Dispersal of risk.
"It needs to worry about mines, RAM, and C-UAS"
You're trying to build a do-everything asset. Wrong approach.
" how does it defend itself on the way back to the ship?"
IT DOESN'T!!!!! As in WWII, the landing craft doesn't defend itself. The landing craft is defended by the battleships, cruisers, destroyers, submarines, and aircraft surrounding it. Not every platform needs to be a do-everything asset. The landing craft has one job and one job only. Someone else does the rest.
We've forgotten every lesson we learned in WWII.
"way to make a beach assault viable"
DeleteIn this day of ubiquitous MANPADS, there's no such thing as a viable, survivable helo and the bigger the load it carries, the bigger the loss of life when it's shot down. Vietnam and Afghanistan proved the vulnerability of helos over a contested battlefield.
Yes, LCUs are great for an initial assault against a Somalia or Gaza situation because they are protected against small arms.
DeleteThe 25 to 100 mile standoff for an assault is simply not feasible. We must come closer to shore and use fire support and suppression to enable operations close to the beach.
Recommend using HIMARS pods and UAVs on amphibs or LCSs for longer range fires and some 120mm mortars for volume of fires. Rifled 120s have an 8400m range which requires the ship to be within 4000m.
Another read that OTH assaults are unfeasible.
Lastly, RHIBs are for raids, infiltration, or reconnaissance during assault prep. In an opposed assault, they would come in after the ACVs.
A few level sets:
Delete- Higgins Boats were landing craft, vehicle, personnel (LCVP) - Carried vehicles
- Landing Craft Personnel (Large) or LCP (L) carried just troops and lacked a ramp initially.
- Both carried 2 .30 cal standard and the LCPL had armor.
These boats were hitting the beach with other small craft carrying additional armament while at the same time getting support from smaller combatants getting in close to the fight. Some of this we may have if we get our act together, most we will not. Plus the actual use of any such boat will be more likely some middle ground rather than an all out direct war. There is a useful boat waiting to be found that may take up the mantle of the Higgins boat, but it isn't going to be a Higgins boat.
"Carried vehicles"
DeleteNot generally in the context we're discussing which is the initial assault waves. The only vehicle it could carry was the jeep which was of no use in the initial assault.
The LCPL was a sub-optimal design (dangerous and inefficient egress) and was succeeded by the LCVP Higgins boat.
The Higgins boat had provision for two small 0.30 cal machine guns although many period photos show them with one or both guns not mounted.
And yes the Marines really need plans to land ashore because most of the world consists of third rate armies. Will the Pentagon tell the President that we can't land in El Salvador or Somalia or Cyprus because we don't do that anymore?
ReplyDeleteNote that LCUs were the main landing platform at Normandy where the US Army had no amphib tracked vehicles. They landed most of the force at Inchon along with LSTs.
DeleteCNO- need to connect at weeks end concerning guest post. But somehow have misplaced the info to do so...
ReplyDeleteabatiedadjj "at" gee mail
This is not WWII, helicopters play critical roles.
ReplyDeleteNot in the initial assault. Vietnam and Afghanistan proved that.
DeleteHelicopters are for fire support. Their assault support role in an opposed landing is very minimal because they carry too small of a personnel load so they require too many sorties to build up a force on the ground. They are also limited to carrying only infantry as there are no useful internally transportable vehicles.
DeleteUkraine proved it even more. I follow the war daily at the "Military Summary" channel. There are never helo assaults or even helo medivacs. The Manpads and drones are too deadly. Russian attack helos once engaged from maximum range, but that was mostly abandoned early this year. Even fast Russian jet aircraft rarely fly low. They dump glide bombs from high altitude miles from the target. And this is despite Russia having air superiority over Ukraine.
DeleteWe talk amphibious assaults. Pentagon won't initiate an amphibious assaults without air supremacy (can you ?). After air attack of an enemy's costal defense, helicopters will land first wave of marines together with their supplies. At the same time, drones and Apache will provide air cover. Once these marines are in positions, these ferried over sea will then land. Even China practice amphibious assaults with helicopter landing even though they have better combat landing vehicles (ZBD-05, etc.). Helicopters play vital roles in today's amphibious assaults.
DeleteIdk... air supremacy doesn't mean safe airspace. Even clearing out all the opposing missile batteries is no guarantee. I think there are far too many handheld threats to expect helicopters to survive until a safe zone has been established...
DeleteTideman Boats out of Holland sells a 10.9m / 3.5m beam / 0.5m draft HDPE plastic-hulled landing craft equipped with a bow ramp. It weighs 4,500kg and has a 3,000kg payload capability, so probably only 24 fully equipped troops. Top speed is 32 knots. Range is 250nm with its 1,000L fuel tank. The engines are 300hp OXE outboard diesels. The boat only appears to retail for 80,000 Euros / $88,800. Each OXE outboard diesel retails for 76,000 Euros $84,360. A Caterpillar C18 might work better for our purposes. It would cost about the same as one of those OXE engines. The OXE is making 100hp/L of displacement, which means it won't last very long at that output level. Their brochure says the craft seats 12, but the only seats I see are for a coxswain and helmsman. It looks like a modern-day Higgins boat to me.
ReplyDeleteThe original Higgins boats were 11m long / 3.3m beam / 0.9m draft, weighed 8,200kg, could carry 3,674kg at most, had a cruising range of 110nm, 833L of onboard fuel, and a top speed of 10 knots when fully loaded, so this would be a significant upgrade. In 1944, Uncle Sam paid $12,000 to $13,000 per boat. Translated to 2024 prices, that's $214,634 to $232,520. Based on the hull and engine cost, we're paying less for a similarly-sized boat that's 3 times faster, has more than double the range, but is only half as heavy. That's a pretty fair deal.
This new model has no mounts for armaments, so that's a bit of a downgrade, but maybe that prevents our Navy from gold-plating a simple transport boat. If we need armed boats to cover the landings, we can purchase other models of those plastic-hulled boats which can mount weapons.
kbd512
I looked at the website but I don't see a 10.9m landing craft. I see a 9.8m version. Is that what you're referring to? It looks like it might hold around 20 troops, standing? It also looks to have fairly short side walls. The Higgins boat had fairly high side walls for some degree of both spray and bullet/shrapnel protection.
DeleteCNO,
DeleteIt's in their sales brochure that I downloaded (model #41 on "Tideman-boats-folder-2023.pdf", page 3 of 5). It's the same physical size, actually slightly larger, than a Higgins boat. Their online configuration and ordering page doesn't appear to show all of their models.
You are correct about the fact that the walls are much higher on the Higgins boat, so I would recommend installing ballistic panels on the sides. They won't stop large caliber bullets, but it should take care of fragmentation.
kbd512
This is the best existing option I've seen so far. I wonder how the 'reverse and pull yourself off the beach capability' is?
DeleteCNO,
DeleteI came up with a compromise solution to reduce engine weight and cost. A Caterpillar C13 engine weighs 1,138kg, much lighter than a C18. It produces 536hp in stock form. If we use aftermarket pistons, it will produce 600hp at max governed rpm. Brand new C13s are $30,000 to $40,000. The pair of original OXE engines only weighed 790kg for both engines, but each engine cost almost as much as the boat itself, and there's no real way those engines can last very long. They're being pushed too hard to show numbers on paper, rather than a realistic continuous power output.
I'm somewhat arbitrarily defining a fully equipped troops as weighing 250lbs each- a 180lb man carrying 70lbs of weapons and equipment. This is a beach assault, so festooning them with weapons and ammo probably won't help them. We can put 24 fully equipped troops in the boat without overloading it. We'd need 30 boats to land 720 troops per wave. As long as there's enough space in the well and cargo decks, moving and carrying a good number of them is not too problematic. 30 of these boats, even with the heavier C13 engine, still weigh 51,300kg less than 24 of the Higgins boats. If we need more firepower for follow-on waves (Javelins, SMAWs, mortars, etc), then we can land smaller numbers per boat, or have men operate those weapons from small support boats.
There's enough space in our smallest well decks (LPD-17s) to carry 20 boats. The largest (LSD-41s and LSD-49s) have enough space in their well decks to carry 53. From that, I conclude that we can land decent numbers of men per wave without risking much more expensive and much slower LCUs or LCMs, which are also much larger targets.
kbd512
I think with the boat size you are looking at you would still want to move 26 for 2 whole infantry squads. Get the whole platoon with any extras in 2 boats.
DeleteYour per man weight is light. You want the upper end, figure 120lbs of gear on a 180lb man. Somewhere in there you want 12 liters / 26.5lb of water so they can make it through a day. I think they speced like 330lb per seat on CH-47s.
On my design I've been using the Cummins 6.7L / 550hp that is being used on the 40' PB and Marines LRUSV for commonality. I use 3 engines, am shooting for 9 boats in a 2 LCAC spot, crew with 3-4 with 76 troop seats (4 x 20 life rafts). That would move 684.
AndyM,
DeleteI really don't think over-loading each man with two thirds of his own body weight is going to help him get off the beach alive. When you move like a turtle because you're effectively carrying another person, your odds of becoming a casualty increase. Carrying 3 gallons of water, in addition to everything else, while someone is shooting at you, is asinine. You will eventually need it, but you don't need to carry it on your person while attempting to assault a beach. Resupply only becomes a problem when you're still counted amongst the living. Part of the reason you would need 3 gallons of water per day is carrying an extra person on your back. I would rather add an extra Marine or even extra boats filled with Marines to an assault wave, if that's what we're resorting to.
M4, 7 magazines, helmet, pair of rifle plates, canteen, small knife to free yourself while being drowned by your own equipment if you go over the side on your way to the beach, and nothing else. Part of the reason behind having Higgins boats was to keep throwing additional manpower at that frontal assault problem. Maybe you could personally "do more" if you had carried this / that / the other with you. Maybe if there were a lot more Marines with you, it would still be a moot point.
As far as the engines go, I know you can make crazy horsepower numbers from tiny displacements. The problem is that engines run that hard continuously don't live very long. For all engines which have continuous power ratings specified by their manufacturers, you won't find any diesels rated for 82hp/L continuous power output, as suggested above. 35hp/L to 40hp/L is about as high as you can realistically go. The 15.2L Cat C13 and 6.7L Cummins are both rated for over 500hp. If both engines were made from the same metals and are similar in design and quality, then I already know which one will last a lot longer than the other. I only need to look at the number in front of the "L" to know that. Foregoing reliability for extra power is a bad trade for a combat boat. If power per unit weight is all-important, then that's why we have gas turbines.
Continuous power output is metallurgy-limited. If we're talking about conventional pistons and crankshafts made from suitable alloys, such as 2618 and 4340, after you exceed mean piston speed or power per unit of displacement limits, the engine is living on borrowed time. With meticulous maintenance, the engine might live longer, or it might not. The bottom line is that no engine manufacturer rates their engines for continuous duty at such high hp/L figures.
kbd512
For any landing over a beach that is contested will require a lot of planning, assuming we want so do it which I doubt (the Marines don't!). There should be enough time to build cheap landing craft during planning. More importantly (Off topic) Is securing a port before the enemy get there and defending it, or taking a port by force. This is more likely to happen at the beginning of a conflict. The appropriate equipment, which may have to be specialist (boats etc), should be available now and practiced with and improved, now.
ReplyDeleteYou can not win a land battle without good port facilities. It is a lot easier to hold a port than take it, so that is where the Marines investment should be. There is also a lot of transferable Capabilities (eg setting up air defense quickly from scratch) Rant over.
Scenarios like WW2 where you start to plan an invasion in 1942 and execute in 1944 are rare and you have time to design and build your assault force. More likely is an amphibious assault against a Gaza or a Houthi group or an assault on a Chinese island that is blocking sea lanes. All of these scenarios are short warning, high risk, and against an opponent that is not armed like Normandy. In reality, any of the currently existing landing methods is adequate if we have sufficient fire support. The focus really needs to be on how to provide sufficient fire support of both the precision long range and the high volume suppression type enabled by good target acquisition. It is really our fire support capabilities that determine what type of enemy we can engage.
DeleteWhy is this all an issue? if we want to make an amphibious landing, the landing force isn't landing by themselves. There'll be as many carrier groups as we can assemble that will be flying top cover and pounding the beaches. The LHDs will be launching gunships to provide CAS for the troops on the beach as they move up.
ReplyDeletePlanning, people. Planning.