MK 71 Lightweight 8" gun.

[sferrin]

Not sure if this is entirely appropriate. It's a naval weapon but it's a gun. Maybe we should add a gun section? ???

At one point it was intended that the forward Mk45 on the Spruance class would be swapped out for these.

 

[TinWing]

Not sure if this is entirely appropriate. It's a naval weapon but it's a gun. Maybe we should add a gun section? ???

At one point it was intended that the forward Mk45 on the Spruance class would be swapped out for these.

There was a revival of this proposal in the early 1990s, leading to the upcoming 155mm AGS.

Oddly, a 175mm design preceded the 8 inch MCLWG. Don't ask me how and why the U.S. Army ever adopted a 175mm and 203 mm guns, and I still don't have a clue whether the MCLWG was related to Army's M110 203mm howitzer?

 

[snurg]

Not sure if this is entirely appropriate. It's a naval weapon but it's a gun. Maybe we should add a gun section? ???

At one point it was intended that the forward Mk45 on the Spruance class would be swapped out for these.

There was a revival of this proposal in the early 1990s, leading to the upcoming 155mm AGS.

Oddly, a 175mm design preceded the 8 inch MCLWG. Don't ask me how and why the U.S. Army ever adopted a 175mm and 203 mm guns, and I still don't have a clue whether the MCLWG was related to Army's M110 203mm howitzer?

I doubt whether the MCGLW was related to the army's 8in howitzer. It is possible, but the USN has a long tradition of 8in guns, and had quite a few in service into the 60's or 70's.

I also remember reading that the 8in design was preceded by 175mm designs, which were terminated as the army was dropping the 175mm. Apparently, the USN had quite large stocks of 8in shells, which also made the 8in design more attractive.

 

[smurf]

Original 8" howitzer muzzle velocity a bit low for naval use, though a longer barrelled version replaced the long range partner gun of 175mm on the M110, but I don't know how the dates stack up.

 

[Jemiba]

For the fans of cut aways :
(from : Norman Friedman "Modern Warship")

 

[Trident]

Nice! It's size is quite apparent in those pictures, one of the few modern naval guns that actually look dangerous

 

[uk 75]

Have finally got my paws on the Norman Friedman US Amphibious ships as recommended to me from this site. If you are interested in the saga of the USN's heavy gunnery efforts in the 60s to the present and the fascinating twin version of the standard automatic 5" US gun and some nice drawings of fire support ships I recommend this book.
On a lateral subject Friedman notes that the automatic guns were supposed to be able to fire fast enough to replace heavier types, but in reality they could not. I think the same thing happened to the RN in the Falklands were the earlier turrets performed better than their replacements, but I may be wrong on that.
The saga of the US Army 175mm gun being replaced by 203mm is well covered in Friedman but also applied NATOwide, including the Rhine Army.
UK 75

 

[RyanC]

Photos of the Mk 71 as installed on DD-945 HULL from NARA:

 

[Abraham Gubler]

Have finally got my paws on the Norman Friedman US Amphibious ships as recommended to me from this site. If you are interested in the saga of the USN's heavy gunnery efforts in the 60s to the present and the fascinating twin version of the standard automatic 5" US gun and some nice drawings of fire support ships I recommend this book.

The Mk 45 was the "lightweight" version of the new 127mm L54 guns. The rival and much heavier Mk 65 was to have a rate of fire of 48 rpm compared to 16-20 rpm of the Mk 45. It was to use pre loaded drums feeding a central carousel.

The Mk 66 was a specialist twin barrel 127mm L54 gun firing from a 100 round drum for the new fire support ships (LFS). ROF would have been 96 rpm and it would have rivaled the exsisting 127mm rocket launchers for area bombardment.

http://www.navweaps.com/Weapons/WNUS_5-54_mk65.htm

On a lateral subject Friedman notes that the automatic guns were supposed to be able to fire fast enough to replace heavier types, but in reality they could not. I think the same thing happened to the RN in the Falklands were the earlier turrets performed better than their replacements, but I may be wrong on that.

The new automatic turrets like the Mk 42, Mk 45 and the British Mk 8 113mm could fire at roughly the same rate as the wartime twin turrets. They also had improved ballistics (range and shell weight) despite the calibre staying the same. The 113mm ammunition of the RN’s Mk 8 is not interchangeable with the twin turret Mk 6.

In the Falklands there were cases of the Mk 8 suffering more frequent mechanical failures than the Mk 6. However you could shoot further with the Mk 8 and no doubt these failures were identified and fixed. In VietNam the RAN stunned the USN (and the RAN) with the effectiveness of the old Daring class destroyer HMAS Vendetta which had to deploy because none of the RAN’s Chalres F. Adams class were available. With three Mk 6 turrets the Vendetta achieved great accuracy, weight of fire and reliability. However to keep this up the CO was often shooting from only two turrets keeping the third down for maintenance. The Vendetta’s heavy 40mm armament was also very useful for maritime interdiction; the shooting up of NVA/VC Junks used to run supplies to the south.

But you can’t really replace a heavier gun like the 203mm with a lighter calibre despite increases in rate of fire. What the heavy shell brings to the NGS mission is increased range, accuracy and shell power to defeat fortifications (including improvised bunkers) and the like. Even heavier shells like the 406mm can also be used to clear beach zone minefields and offer further improvements in accuracy and destruction of fortifications. What is interesting is how these dynamics will be changed by guided rounds like the 127mm BTERM and 155mm LRLAP.

 

[Pioneer]

I find the information on the Mk 66 barrel 127mm L54 gun very interesting
Thanks for bring it up!
I think the drive for lightweight may have gone too far in Western Navy at some time - hence why I agree and understand the statement

In the Falklands there were cases of the Mk 8 suffering more frequent mechanical failures than the Mk 6. However you could shoot further with the Mk 8 and no doubt these failures were identified and fixed. In VietNam the RAN stunned the USN (and the RAN) with the effectiveness of the old Daring class destroyer HMAS Vendetta which had to deploy because none of the RAN’s Chalres F. Adams class were available. With three Mk 6 turrets the Vendetta achieved great accuracy, weight of fire and reliability. However to keep this up the CO was often shooting from only two turrets keeping the third down for maintenance.

Isn't it some what ironic just how much the West had to relearn after the Falkland Islands War of 1982. And yet in someways we still have not implemented these lesson's or think we know better once again!

Where the West went through a period of discarding the purpose built gun mount on their modern warships, it appears that the Soviet's knew something or just didn't forget when they developed and fielded the 130 mm/70 AK-130 twin DP mount.
Saying this maybe a Mk 66 twin 127mm or 114mm type mount has a lot of merit!
But then again we in the West would probably over-engineer it, make it way to costly and if the U.S Navy is behind its development - cancel the whole program at the time it has been proven and perfected!

P.S. I think in the West the reverting back to the likes and the capability of the warrented 203mm Mk 71 is and will always run up against the likes of the missile lobby in our navies - Pity!!!!

Regards
Pioneer

 

[Pioneer]

The Mk 66 was a specialist twin barrel 127mm L54 gun firing from a 100 round drum for the new fire support ships (LFS).

Sorry a little of topic - but does anyone have anything on this proposed Fire Support Ship (LFS)
and what time period was the Mk 66 twin 127mm mount program?

Regards
Pioneer

 

[Sea Skimmer]

There was a revival of this proposal in the early 1990s, leading to the upcoming 155mm AGS.

Oddly, a 175mm design preceded the 8 inch MCLWG. Don't ask me how and why the U.S. Army ever adopted a 175mm and 203 mm guns, and I still don't have a clue whether the MCLWG was related to Army's M110 203mm howitzer?

The US Army adapted a 175mm gun because with the technology of the time this caliber was necessary to achieve significantly greater ranges then the M1 155mm gun was capable of for the counter battery mission. The specific caliber choice was driven by the success of the German 17cm K 18 in WW2, and older work involving the French 194mm GPF. The Soviet adoption of the 180mm S-23 long range gun in the mid 1950s was further driver, though at the time the US actually thought this was an 8in weapon since we only had photos to scale from. It wasn't until 1973 that Israel captured a few and the truth was learned.

The US Army only ever had an proper 8in gun during WW2 (we had railroad pieces in WW1), which had to transported in two pieces and shared a carriage with the 240mm howitzer. A 20 ton truck crane assembled them in position, though winches and A-frames could also be used. Both were tested on self propelled mountings using the Pershing Tank, but the war ended before either was mass produced. Both weapons were retired in the mid 1950s when we ran out of ammunition for them. The 240mm howitzer saw action in Korea, but not the 8 inch gun. A single prototype of a 240mm gun was produced, which is on display in Virginia. It formed the basis for the postwar 280mm atomic cannon.

All postwar US 8in weapons are howitzers with significantly shorter range and much less weight. The Navy 175mm and then 8in program would have shared ammo with the Army, but not any piece of the gun itself.

 

[Abraham Gubler]

Sorry a little of topic - but does anyone have anything on this proposed Fire Support Ship (LFS)
and what time period was the Mk 66 twin 127mm mount program?

Friedman's "U.S. Amphibious Ships and Craft" has a whole chapter on the development of LFS in the late 60s and then later in the mid 80s. None of these ships were built and they included several purpose built designs and conversion of the Spurance class design. A quick summary of the designs is:

1967 high end LFS: 8,000 tons, 2x 203mm, 2x Mk 45 127mm, 8x Mk 105 127mm rocket launchers, one landing force fire support weapon (LFSW) a Lance type missile launcher
1967 monitor LFS: 9,000 tons, 3x 406mm, 1x 175mm, 2x Mk 42 127mm
1968 LFSR: 7,825 tons, 2x 175mm, 4 x Mk 45 127mm, BPDMS, 12x Mk 105 launchers
1969 inshore LFS: 2x 175mm, >4x Mk 105 launchers
1970 Spruance LFS: 7,461 tons, 2x MCLWG, 1x Mk 45 127mm, BPDMS, ASROC
1970 LFS: 7,856 tons, 3x Mk 71 203mm, 2x Mk 66 twin 127mm, BPDMS
1986 LFS v3: 1x Mk 71 203mm (500 rounds), 1 x MLRS (900 rockets), 2x Phalanx
1986 LFS v4: 2x Mk 71 203mm, 2x Phalanx
1986 LFS v7: 2x Mk 71 203mm, 2 x MLRS, 2x Phalanx

 

[Pioneer]

Thanks heaps for this info Abraham Gubler
These look very impressive proposals/programs
Are there any drawings/artist impressions to go with these ? ??? ;D

One thing that I have never completely understood is the US Navy's apparent reluctance to consider, let alone field a navalized variant of the army's MLRS system!
Ok some people would say that to use them would bring US Amphibious units into harms way!
Some would say that the loading/reloading process is unacceptable on a ship!
Its strange - but as far as multiple rockets launchers on Western/NATO ships go in the amphibious support fire role, I think only the Italian navy utilize them aboard there ships(??)

Regards
Pioneer

 

[Abraham Gubler]

These look very impressive proposals/programs
Are there any drawings/artist impressions to go with these ? ??? ;D

Yeah there are a bunch of SCB drawings. But bear in mind that this is a freely available book and its not the policy of this web forum to copy stuff from books… If you have access to a university or state library they should have a copy of Friedman’s books.

Also parts of this book are available online at Google Books:

http://books.google.com/books?id=oWX-x0b4pw4C&printsec=frontcover&dq=u.s.+amphibious+ships+and+craft&cd=1#v=onepage&q=&f=false

Including much of the chapter on the LFS options (Fire Support Revisited).

One thing that I have never completely understood is the US Navy's apparent reluctance to consider, let alone field a navalized variant of the army's MLRS system!
Ok some people would say that to use them would bring US Amphibious units into harms way!
Some would say that the loading/reloading process is unacceptable on a ship!

Well that’s not true. The US Navy has extensively considered, trailed and designed naval MLRS and ATCAMS in both trainable launcher and vertical launcher options for their ships. Its just they haven’t had the money or got sidetracked into 155mm artillery options, which is a great shame because MLRS is ideal for NGS. It can do all the missions required with a single system (albeit with three different rocket types).

Its strange - but as far as multiple rockets launchers on Western/NATO ships go in the amphibious support fire role, I think only the Italian navy utilize them aboard there ships(??)

The Italians like the Israelis have rocket launchers on their ships mostly for launching decoys. The US Navy on the other hand has fired more rockets from their ships than the rest of the world combined. The LSM(R) and IFS types perfected the mass bombardment area rocket capability. This enabled a single ship to shoot up to 400 127mm rockets per minute for 30 minutes. Was to be replaced by the Mk 66 twin barrelled 127mm L54 gun which in a four turret, 750 rpg ship would provide the same capability but with better range, accuracy and far more compact ammunition storage.

 

[Madurai]

The 175mm version of the MCLWG would have been able to use Army ammo stocks--and indeed that was why the caliber was selected--but the 8" would not. It was designed to use the stocks of fixed-round ammunition formerly used by the Mark 16 8"/55 RF guns from the Des Moines class.

 

[DanielStarseer]

Hey all,
long time lurker and just recently joined.

In discussing naval gunfire support, and the inclusion of MLRS developments,
has there ever been in the past mention on any of the threads here about Lockheed Martin's POLAR derivative of the MLRS rocket ?
(Precision, Over-the-horizon, Land Attack Rocket)

Have seen it discussed numerous forums elsewhere, but sadly can't seem to find a lot of solid evidence of it anymore thru the web.

From what I recall,
by the standard MLRS rocket's 9" diameter dimesions, it should've ideally quadpacked into VLS cells similar to the larger diameter (10 inch rocket motor casing) ESSM Evolved Sea Sparrow.
Suggested range was (hoped for?) in the neighborhood of 180km, and IIRC a unitary warhead was the preferred payload.

Notice how this compares to the latest G-MLRS rockets that utilize a 90kg unitary warhead and ranges approaching 90km...there's obviously some useful design life left in the MLRS form (a ship version could be longer than the podded rockets used by land-based launch vehicles),
or even greater capability to be achieved if a fire support system is designed utilizing the 10" body of the ESSM.

This certainly merits consideration for longer-ranged fire support, since obviously the USN isn't going to be producing many of those DDG1000 destroyers with their two 155mm guns and Long Range Land Attack Projectiles...with a POLAR/ESSM derivative, any VLS-equipped ships capable of using SeaSparrow type missiles could thus function as fire support ships.
(seems an easier solution than sinking development money into a new gun mounting...)

 

[Abraham Gubler]

Hey all, long time lurker and just recently joined.

Welcome.

In discussing naval gunfire support, and the inclusion of MLRS developments,
has there ever been in the past mention on any of the threads here about Lockheed Martin's POLAR derivative of the MLRS rocket ?
(Precision, Over-the-horizon, Land Attack Rocket)

Most of this forums history is in aircraft projects with navy and army projects being recent additions. There is also a very good search tool but there is little on MLRS and nothing on POLAR here before this thread.

POLAR was proposed by Lockheed in 1999 as a contender for the US Navy’s abortive land attack missile requirement: won by Raytheon with the LASM, aka SM-4, converted high time SM-2s to land attack.

POLAR was an evolution of the then in development GMLRS but with the bigger (by 30%) rocket motor for longer range. The bigger motor enabled stand off range outside expected coastal defences and compensated for loss of range thanks to vertical rather than slant launch.

This certainly merits consideration for longer-ranged fire support, since obviously the USN isn't going to be producing many of those DDG1000 destroyers with their two 155mm guns and Long Range Land Attack Projectiles...with a POLAR/ESSM derivative, any VLS-equipped ships capable of using SeaSparrow type missiles could thus function as fire support ships.
(seems an easier solution than sinking development money into a new gun mounting...)

I agree. While a GMLRS type rocket like POLAR tends to cost around 5-10 times more than a ERGM or LRLAP it can achieve lower cost per kill thanks to its higher payload delivery (4.6 times the bomblets compared to LRLAP) and lower volume/weight per kill. The equivalent of a full AGS 155mm gun turret and magazine (600 rounds) could be meet by only half a 64 cell Mk 41 VLS loaded with 32 quadpacked canisters for POLAR. Obviously the efficiencies of using existing Mk 41 VLS launchers compared to the AGS gun system are immense.

Here is a POLAR picture from an old Armada magazine.

 

[DanielStarseer]

Thanks for the Welcome.

WRT to the LASM, funny thing there is, is it even in service?
Other than forum discussions and pictures depicting various VLS cell load outs, I've seen little mention of it.

Could be it's been considerably back-burnered so as not to detract away from the AGS/LRLAP program,...? (speculation on my part)

As to costs, I don't know that I'd give benefit of the doubt to 5" types (ERGM, BTERM, etc) and LRLAP costing less than these POLARs (longer-bodied GMLRS): the MLRS rocket lines already are in production status, so the tooling shouldn't be too complicated to ramp into the POLAR derivative when GMLRS production isn't needed (plus it conserves jobs and the tech pool).
The US has faltered repeatedly on guided shell programs for its 127mm ship guns, always seeming to bail out at the last minutes as the tech is finally starting to show promise.

I don't have much faith that the 155mm AGS' LRLAPs will be cheap, either: even if magazine capacity is stated as ~600 rounds, that's still gonna be a mighty expensive warload to fill just one DDG1000's two gun magazines.
And keep in mind also, these rounds, impressive as they may be, are pretty much going to be hull-specific to the DDG1000 class.
If by some grace-of-the-naval-gods the USN pursues an adhoc 155mm deck gun for retrofit to ships currently mounting 5-inch guns (M777-based? The titanium construction would hold up better under seawater environment, I believe),
these LRLAPs are of such a size (length) that they'd need to be manually-loaded,..unless, of course, a turret configured the likes of the 8" Mk71 is brought into service...but with a 155mm tube (to move 8" shells, the Mk71 obviously has more internal room for larger shells than a Mk45 127mm turret).
Still, at several feet shorter in length than the AGS' barrel,
I don't believe any 155mm weapon shorter than the AGS' 55-cal tube will fire the LRLAP as far...

I think the USN flubbed considerably in abandoning the Mk71, if naval gunfire support is supposedly going to be so prominent in the future (that in itself is, perhaps, a USN/USMC desire based solely on adoption of the AGS program, possibly,...?).

Still, a fascinating what-if solution that certainly still has some merit behind it (both POLAR and the Mk71...hell, even a derivative lightweight 155mm naval gun could at least fire Excalibur projectiles, even if those are "only" rated to ~40km ranges...

It has been mentioned the Israelis' preference/experience with surface-to-surface rockets from ships: they use several different rocket body diameters in their land systems that, with the current developments in precision guidance as aftermarket add-ons, they certainly have a lot of potential cheap SSMs suitable for a majority of littoral targets.

Hopefully, the USN will wake up and and at least further put more effort into finalizing a working 127mm design...saw in tests that a few reached like 60 nautical miles, not bad at all.

(I'm still working out how everything functions posting here,...give me a little time to work up to linking status...)

 

[Abraham Gubler]

WRT to the LASM, funny thing there is, is it even in service?
Other than forum discussions and pictures depicting various VLS cell load outs, I've seen little mention of it.

RGM-165 aka LASM, SM-4 was cancelled in 2002 supposedly because of its limited capability to engage mobile and hardened targets but really for cost. 800 SM-2s were to be converted with the first entering the fleet in 2003/04.

Could be it's been considerably back-burnered so as not to detract away from the AGS/LRLAP program,...? (speculation on my part)

Yeap.

As to costs, I don't know that I'd give benefit of the doubt to 5" types (ERGM, BTERM, etc) and LRLAP costing less than these POLARs (longer-bodied GMLRS):

I’m quoting ATK for that cost bracket. Though USA defence unit costs are available openly and online just not laid out in such a nice cost comparison.

I don't have much faith that the 155mm AGS' LRLAPs will be cheap, either: even if magazine capacity is stated as ~600 rounds, that's still gonna be a mighty expensive warload to fill just one DDG1000's two gun magazines.

Especially since they can only fire LRLAPs and can’t load conventional 155mm ammunition because it won’t work in the AGS.

If by some grace-of-the-naval-gods the USN pursues an adhoc 155mm deck gun for retrofit to ships currently mounting 5-inch guns (M777-based? The titanium construction would hold up better under seawater environment, I believe),these LRLAPs are of such a size (length) that they'd need to be manually-loaded,..unless, of course, a turret configured the likes of the 8" Mk71 is brought into service...but with a 155mm tube (to move 8" shells, the Mk71 obviously has more internal room for larger shells than a Mk45 127mm turret).

No that wouldn’t work. A gun like the M777 can’t fire LRLAP. Even if you could fit it in the bore you couldn’t develop enough chamber pressure to send it anywhere significant. Except for the tube size there is no commonality between AGS 155mm and NATO standard 155mm. There are several naval turret NATO standard 155mms under development including a British turret and a Navalised version of the German AGM (aka Donar). Anyway such a conventional 155mm offers little in advantage to legacy 127mm L54s except a single source of ammunition production.

I think the USN flubbed considerably in abandoning the Mk71, if naval gunfire support is supposedly going to be so prominent in the future (that in itself is, perhaps, a USN/USMC desire based solely on adoption of the AGS program, possibly,...?).

Well not quite because they didn’t go from Mk 71 to AGS. The intervening stop was VGAS which fired the 155mm LRLAP through two fixed vertically mounted barrels. Combined with ~1,500 LRLAP rounds this assembly would fit into the same space as a 64 cell Mk 41 VLS. VGAS was very capable and efficient and accessible to a range of ship designs. Unfortunately (EDIT) the dumb arse Congress (end EDIT) decided that the new 155mm gun need to be able to fire conventional dumb ammunition so demanded it be redesigned as a trainable, elevating turret mount. What then happened was so much money was spent on the turret that none was available to develop the compatible 155mm conventional ammunition. So AGS like VGAS could only fire LRLAP but was far more costly, complex, volume and weight consuming and limited to purpose designed ships.

http://www.secretprojects.co.uk/forum/index.php/topic,689.0

 

[TomS]

There are a couple of corrections needed here. I was working in support of the Navy's surface combatant Progam Office in the late 1990s, and was specifically responsible for media monitoring and strategic communications, so I think I had a pretty goood grasp of what was going on with respect to the programs.

1) The Navy had two major (non-cruise missile) land-attack missile projects in the 1990s -- the interim land-attack missile in roughly 1996-1997, and the Advanced Land Attack Missile that was part of the DD-21 program. For the interim program, LASM beat out Naval ATACMS in late 1997, though the Navy continued to discuss buying both missiles into early 1998. ALAM never reached the competition stage (they only issued a draft requirement), but NTACMS was considered the leading candidate.

As attractive as it was in concept, POLAR did not compete in either of these requirements. POLAR was a Lockheed company initiative announced in 1999 and it never really matched up with any stated Navy program. It was too late for the interim missile requirement and would not have been responsive to ALAM, since that required a range of at least 200 nautical miles. If anything, it was seen as a fall-back for guided gun rounds, rather than as an alternative to longer-ranged strike missiles.

2) It was not the Navy that rejected VGAS, it was Congress. I've posted the relevant links before, so I won't do so again, but the gist is that Congress declined to allow the Navy to proceed with VGAS unless it did a tradeoff study against trainable guns. That's clear in the congressional records of the day. Behind the scenes, it was made clear that certain members of Congress felt VGAS was too inflexible and insisted on trainable guns due to their supposed utility in surface warfare (attacking small boats, etc.). There was lot of heartburn over this within the program office, but the conclusion was that this wasn't a winnable fight, so they acquiesced.

 

[Abraham Gubler]

There are a couple of corrections needed here. I was working in support of the Navy's surface combatant Progam Office in the late 1990s, and was specifically responsible for media monitoring and strategic communications, so I think I had a pretty goood grasp of what was going on with respect to the programs.

Thanks for the more information.

 

[Sea Skimmer]

No that wouldn’t work. A gun like the M777 can’t fire LRLAP. Even if you could fit it in the bore you couldn’t develop enough chamber pressure to send it anywhere significant. Except for the tube size there is no commonality between AGS 155mm and NATO standard 155mm. There are several naval turret NATO standard 155mms under development including a British turret and a Navalised version of the German AGM (aka Donar). Anyway such a conventional 155mm offers little in advantage to legacy 127mm L54s except a single source of ammunition production.

The British turret is beyond dead for lack of money in the RN for even more basic capabilities like torpedo tubes on the Type 45. The Germans abandon the naval Pz2000 turret was well, because it corroded in seawater. Changing everything to avoid this would amount to designing a new turret. The French project died even earlier.

 

[Abraham Gubler]

The PzH2000 turret on a German navy frigate was only a demonstrator. KMW now market their unmanned AGM turret as a possible naval solution. Obviously there is not that much interest in giving up 127mm.

An interesting point related to the earlier discussions is the US Navy actually did some work on shooting MLRS 9" rockets out of an ASROC launcher.

 

[Sea Skimmer]

Yeah it did, but POLAR was only going to get built if we also built Arsenal Ship and tried to replace the volume of fire provided by 16in shells on a one for one basis with guided missiles. 512 Mk41 cells quad packed with POLAR would do that nicely. This was not very realistic, nor necessary. Meanwhile the unreality of desired USMC fire support requirements for range, volume and response time pretty much ensures nothing will ever be fielded to met them. SM-4 could fly far enough, but not with the numbers and even then its mach 3+ speed was not truly sufficient, nor could we ever hope to field enough specialist versions of the weapon to provide critical pieces of fire support like smoke cover.

It isn’t even clear now that the mere three DDG-1000s to be produced will even have the Advanced Gun System which continues to show major technical problems and will likely never met anything like its claimed range specs. It won’t be surprising if they are completed with 5in 62cal guns or even nothing heavier then the 57mm battery. Its not like they’ll ever be used in combat. Test ships for life.

 

[Abraham Gubler]

The USMC fire support requirements for amphibious assault are not unrealistic. They are based on what is actually required to achieve the mission from mine clearance through to more traditional offensive support. Added to that is the recent US Navy mission for sea based interdiction of land targets requiring rapid and deep strike. That the US Navy does not have a ship platform to provide the marine’s fire support does not mean it isn’t provided. It means more carrier support is required for each amphibious assault with the strike aircraft dropping bombs where rockets and shells would comply.

The three single 8” Mk 71 and two twin 5” Mk 66 gun combination in the ~5,000 tonne LFS classes proposed in 1970 could have provided the greater bulk of the fire support required for an amphibious assault. With contemporary capabilities like PGK and ERGM it could also evolve into providing a lot of deeper fires capabilities required for sea based interdiction. Imagine a 160 kg / 350 lb 8” ERGM shell?

The disaster that is the DDG 1000 is what happens when the solution to the problem is manipulated in committee for 30 years before being built.

 

[Sea Skimmer]

The USMC fire support requirements for amphibious assault are not unrealistic. They are based on what is actually required to achieve the mission from mine clearance through to more traditional offensive support.

Just because you can find a reason to ask for a capability does not mean its realistic to try to field that capability. The Marines are seeking to change the entire way they fight and conduct a landing, with the navy providing all artillery support for missions requiring more then a 120mm mortar. They’ve got reason to ask for that since modern weapons would crush a conventional beachhead and helicopter landing zones, but it doesn’t mean will find a good solution.

Added to that is the recent US Navy mission for sea based interdiction of land targets requiring rapid and deep strike. That the US Navy does not have a ship platform to provide the marine’s fire support does not mean it isn’t provided. It means more carrier support is required for each amphibious assault with the strike aircraft dropping bombs where rockets and shells would comply.

Air strikes can’t meet the response times, unless you already have a plane in the air with the proper load out. This is not realistic then a Marine Expeditionary Strike group will have maybe 6-10 Harriers or F-35s to utilize for all roles. Advanced Gun System can’t meet the response times either for that matter, the shell just takes too long to glide to 100nm, not that it has been tested that far in the first place. IIRC they’ve gotten to about 65nm.

As a bigger problem air strikes lack sustainment. One air strike can cause much more damage then an artillery barrage, but the artillery can just keep falling to keep an enemy suppressed or lay down a final protective fire. These are vital artillery missions, and if a warship based system can’t replace them then the Marines need to go back to air landing 155mm howitzers very early on in an invasion. They don’t want to do that because towed guns are slow and clumsy to move, and would require a lot of airlifted ammo. But sometimes you don’t get to do what you want.

The three single 8” Mk 71 and two twin 5” Mk 66 gun combination in the ~5,000 tonne LFS classes proposed in 1970 could have provided the greater bulk of the fire support required for an amphibious assault.

It was still a 175mm gun back then. But anyway for a conventional over the beach assault, sure that works fine. But now the USN wants 25nm minimal stand off range, and the Marines want; to be able to support a landing at least 50nm inland. Providing counter battery support for that landing requires another 25nm of reach, so you need a weapon that can shoot at least 100nm. This is further then the Paris gun or 21cm K12 could throw a shell with a barrel over 100 calibers long. The 8in Mk71 and undeveloped Mk66 mount are no closer to doing this then any number of other abortive programs or future napkinwaffen concepts.

With contemporary capabilities like PGK and ERGM it could also evolve into providing a lot of deeper fires capabilities required for sea based interdiction. Imagine a 160 kg / 350 lb 8” ERGM shell?

The AGS shell already weighs 200lb, so its not hard to imagine. However its still very demanding to make a shell like that fly far enough without gliding. ERGM and AGS glide, that makes them slow to response, much more so then a 155mm towed battery firing a shell 20 miles or less, and very expensive and time consuming to develop. That's besides the costs of fielding a dedicated bombardment ship. In the 1970s that could have happened. In the modern day, no way. Whatever the solution, if any, it has to be able to go on a wide range of ships so our numerous Marine Ready Groups and Strike Groups can all have fire support at hand.

The disaster that is the DDG 1000 is what happens when the solution to the problem is manipulated in committee for 30 years before being built.

That plagues everything the US military touches, and will plague new solutions as much as the existing ones.

 

[Abraham Gubler]

Air strikes can’t meet the response times, unless you already have a plane in the air with the proper load out. This is not realistic then a Marine Expeditionary Strike group will have maybe 6-10 Harriers or F-35s to utilize for all roles. Advanced Gun System can’t meet the response times either for that matter, the shell just takes too long to glide to 100nm, not that it has been tested that far in the first place. IIRC they’ve gotten to about 65nm.

Which is why an MEU with an amphibious assault mission is supposed to have 2 CSGs able to provide >40 strike fighters 24-7.

That's besides the costs of fielding a dedicated bombardment ship. In the 1970s that could have happened. In the modern day, no way. Whatever the solution, if any, it has to be able to go on a wide range of ships so our numerous Marine Ready Groups and Strike Groups can all have fire support at hand.

Which is why the interest in this thread with the naval MLRS/POLAR concept type of missile. Because this is the sort of system that can consume 32 VLS cells on each destroyer or LCS providing each surface combatant ship with 128 missiles. 16 surface combatants equals one arsenal ship and they can each do they naval warfare tasks while on hand for call to fire. Obviously GMLRS has only half the range of the 75 NM mission (when slant launched). But a GMLRS is under 4m long and the VLS canister can hold a missile up to 6.25m long.

 

[DanielStarseer]

Like how the discussion's been going, guys.

WRT using modern POLAR variants,
yes, we can see that current G-MLRS rounds don't have the favored ~100nm range,...but also remember, the G-MLRS has a ~90kg warhead (saw somewhere suggesting it was carrying 22kg of actual explosive content...or was that the LRLAP?).
This is a much larger warhead (bursting charge/lethal mechanism) than any of the artillery tube-based systems.
So is there any reason why we couldn't sacrifice warhead (payload) capacity to fit a longer rocket motor that would give us this supposed favorable ~100nm range?

Curious to see how the latest in Techno-WondermentTM would make POLAR perform today (do we just dust off the original 1990s specs, or try it new with the latest propellant tech and electronics/electromechanics and strake wings as in the G-MLRS+ types now coming along?).

The other option there is Lockheed Martin's P44 design, a ~7inch diameter munition that, in MLRS pod form, replaces a 6-cell (~9inch diameter) MLRS pod with a 10-cell P44 pod, claiming P44's had the multimode seeker option that NLOS-LS/PAM is going to use, with Hellfire-class warheads (to about 28 lbs, IIRC), and ~70km ranges.
(numerous links abound for the P44,... http://www.pcb007.com/pages/zone.cgi?a=14938&z=68&v= )

Yeah, it still comes considerably shy of 100nm, but it still outranges the only other
alternative easily-fielded-in-large-enough-numbers missile, the NetFires PAM, (~40km as it sits now, and also an unpowered glider at its maximum range).

I'm just guessing here, but it seems reasonable that the longer P44 airframe, even with an unpowered terminal glide approach also, most likely would still impact targets faster (but not necessarily get farther, faster), being boosted higher in their trajectory than PAMs, so having greater KE built up in a longer glide/dive,...?


Seeing as 5inch guns obviously aren't going away anytime soon, further development of their guided projectiles seems an obvious course of action.
But there again, not everyone has ships fitting 5inch guns, but would certainly still like effective, ACCURATE, stand off surface attack firepower.

POLARs and P44s seem like they'd offer the closest to what the USMC deems it needs.
Either would give favorable warhead weight, multimode seekers, and massed numbers, but the biggest drawback being lack of desired range.

At the other end of that spectrum, anything offering those ranges, ~100nm, are big and expensive, and hard to produce in sufficient quantity for that reason,
let alone being much larger and needing more space on a given ship, meaning less will be carried, etc...(such a vicious trade-off cycle).

The only other alternative to these and the obviously limited number of AGS/LRLAPs
is another expensive program,
this time to develop ramjet-powered (long range and high speed) missiles that offer
an effective-enough warhead, multi seeker options, and packable in ships in sufficient quantity, which means they can't be too expensive.
Tough sell on that one.
And ideally, utilizing current VLS systems is an obvious plus (attracts many more customers).

As nostalgic as those big deck guns and all their flame-belching booming power is, I just don't see them making a comeback (not even in the AGS, not successfully anyway) in large enough numbers to make much difference.

 

[Abraham Gubler]

yes, we can see that current G-MLRS rounds don't have the favored ~100nm range,...but also remember, the G-MLRS has a ~90kg warhead (saw somewhere suggesting it was carrying 22kg of actual explosive content...or was that the LRLAP?).

The warhead on the GMLRS is similar to the shell of an 8 inch (203mm) gun. Which is about as close to ideal for field artillery effect as you can get. Great for frontage in barrages and great point destruction on delay for taking out bunkers.

 

[sferrin]

Technical Evaluation of the 8-Inch Major Caliber Lightweight Gun Mount, Mark 71 Mod 0. (All 39 Mb.)

https://apps.dtic.mil/dtic/tr/fulltext/u2/907961.pdf

 

[TomS]

That's an interesting read. Sounds like if there was a real problem at this stage of the testing, it was that the ammunition sucked. Hardly surprising since it seems to have been basically war surplus stock.

 

[Pioneer]

Wow, found this both very cool and interesting!!

Laser-guided 8" (20.3 cm) Paveway or CLGP (Cannon Launched, Guided Projectile) round, developed in the 1970s at Dahlgren Laboratory, Virginia.

USS Hull made 5 out of 5 hits on moored ex-destroyer target USS Burns (DD-588) in June 1976 using these projectiles.

(Source: NavWeaps. http://www.navweaps.com/Weapons/WNUS_8-55_mk71.php)


Regards
Pioneer

 

[Pioneer]

Oh, and this planned load out if Spruance Class adopted the Mk71 -

The planned ammunition stowage for the Spruance class (DD-963) was as follows:

The first platform magazine (Fr. 77-94) held 129 ballistic projectiles, 119 standard propellant charges and 32 reduced charges.

The second platform magazine (Fr. 58-94) held 256 ballistic projectiles, 266 standard propellant charges, 40 Guided Projectile (GP) charges and 24 clearing charges.

The third platform magazine (Fr. 58-94) held 40 guided projectiles.

Including the ready service drum, the total ammunition stowage was 500 projectiles (ballistic and guided) and 556 propellant charges (standard, reduced, clearing and GP)

.

(Source: NavWeaps. http://www.navweaps.com/Weapons/WNUS_8-55_mk71.php)


Regards
Pioneer

 

[sferrin]

Oh, and this planned load out if Spruance Class adopted the Mk71 -

The planned ammunition stowage for the Spruance class (DD-963) was as follows:

The first platform magazine (Fr. 77-94) held 129 ballistic projectiles, 119 standard propellant charges and 32 reduced charges.

The second platform magazine (Fr. 58-94) held 256 ballistic projectiles, 266 standard propellant charges, 40 Guided Projectile (GP) charges and 24 clearing charges.

The third platform magazine (Fr. 58-94) held 40 guided projectiles.

Including the ready service drum, the total ammunition stowage was 500 projectiles (ballistic and guided) and 556 propellant charges (standard, reduced, clearing and GP)

.

(Source: NavWeaps. http://www.navweaps.com/Weapons/WNUS_8-55_mk71.php)


Regards
Pioneer

There's a picture of an advertisement showing an artist's concept of a Spruance with a Mk71 up front on the board somewhere. I'll post it in this thread later if nobody else has by then.

 

[TomS]

I'd love to see that picture. I poked around briefly and couldn't find it. ISTR that the Spruance could only take an 8-inch forward because there is insufficient hull depth aft for a second mount. So a retrofit would have ended up with an odd situation of having both 5-inch and 8-inch guns on the same ships.

 

[cjwilks]

Here's an FMC rendition of a 8"/ 60 Mk 71 mounted on Spruance DD. I can't remember where I got it from, maybe Cmdr. Salamander's blog. No, I got it from NAVWEAPS (TAPTALK). the attachments are awaiting approval.

 

[TinWing]

Here's an FMC rendition of a 8"/ 60 Mk 71 mounted on Spruance DD. I can't remember where I got it from, maybe Cmdr. Salamander's blog. No, I got it from NAVWEAPS.

The attachment doesn't show up.

 

[sferrin]

I'd love to see that picture. I poked around briefly and couldn't find it. ISTR that the Spruance could only take an 8-inch forward because there is insufficient hull depth aft for a second mount. So a retrofit would have ended up with an odd situation of having both 5-inch and 8-inch guns no the same ships.

Damn. Forgot. "Note to self. . ."

 

[TomS]

Here's an FMC rendition of a 8"/ 60 Mk 71 mounted on Spruance DD. I can't remember where I got it from, maybe Cmdr. Salamander's blog. No, I got it from NAVWEAPS.

The attachment doesn't show up.

I think only people with certain number of posts can add attachments.