The Ship Model Forum

Weight is certainly a concern – we don’t want her bows driving deep into the waves - that is why I removed the fwd VLS to compensate. Taking that weight out, the adding the Mk 71/ Mk 110 combination should be a near break-even point, with the additional ammunition we are talking about finally eating margin.

Keep in mind the reason for this mental exercise is insufficient NGFS at this time. At this time NGFS ability is best captured by Mk 45 with 600 rounds. DDG-51’s only mount one weapon of this type, so we have already halved the volume of fire as compare to the Spruance class. It is unlikely that a Tico will be used in this role.

So:
1. The number of mounts is insufficient
2. The caliber of mount is insufficient (will not generate the desired effect reliably enough)

To settle for fewer rounds on that single mount exacerbates both of these issues.

As the initial proposal was to modify and existing platform with a reasonable chance of the refit actually taking place, mounting a second weapon is probably out of the realm of possibility. So, we can’t reasonably do anything about issue #1 in this particular application. That will have to be addressed with an all-new, or modified, design.

So, this leaves us with modifying the existing mount, in this case to the Mk 71. This at least addresses issue #2.

Simply put, I’d like to see two weapons with 600 round each as a minimum. I can’t get a second mount in this case without breaking my own target of having a simple refit to increase likelihood of the fit actually being carried out.

I am concerned that increasing caliber and decreasing available ammunition will make a break-even point, not an enhancement, for gunfire capability. Yes, round-for-round the 203mm will win, but if it only has 2/3rds the ammunition, how long will that edge be maintained?

IF the single mount can be upgraded from 127mm to 203mm,

-At 411 rounds you have increased effectiveness through greater range and enhanced destructive effect on a given target. You will decrease the rounds needed on a fire for effect mission because each round has a greater effect, but may be giving up the ability to engage as many targets before replenishment.

-At 600 rounds you have certainly made a major improvement by increasing destructive effect on at least as many targets as before the refit.

-If you can exceed 600, you begin to make some inroads to issue #1 by increasing sustainment of that fire.


Further magazine capacity increases the options for derivative loads later on – specialized shells and sufficient basic projectile for whichever the fire mission calls for. This is the spirit of the fight in, fight long, fight out concept that we are pushing for here.

I will use 366+75 if that’s all I can get, but I’d like to see more.



While I don't think volume would be an issue, where did the 3x number come from? Is that from raw weight of each projectile?

You know that the 203mm/55 Mk71 gun's design was not kept up to date with Navy specifications and requiements since it was canceled in 1980. Its electronics are incompatible with current systems. New electronics will need to be designed using integrated circuits rather than vacume tubes. Some of the metals that are design specifications are no longer produced. And some of the design work to complete the gun design was never completed and the designers have retired and/or passed since the cancelation. The current 155mm gun designed for DDG-1000 started off as the Mk71.

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Indeed. BAE owns the Mk71, they used it as a starting point to make their modernizations to meet the Navy's request to utilize commonality of ammunition with the Army (155mm) and produced the AGS. The Navy was not interested in effective utilization but least common denominator.

The a lower-cost and more effective alternative is utilizing the Mk71 Mod0 and take the lessons learned from its utilization aboard the USS Hull and on land at Dahlgren to produce the Mod1. These would be altered rifling twist, 60caliber barrel, longer recoil slide to accommodate the 332lb AP round, and recoil reduction. Because the Mk71 has 80% compatibility with the Mk45, the modifications made to the Mk45 to bring it up to modern standards with compatible digital systems and power (the Mod 4 modernization) can be equally applied to the Mk71 to bring it up to modern compatibility standards without modifying the structural requirements of the mount. I am will to speculate that the three main reasons they chose the 155mm over the 8-inch in their 2003 evaltuation of the project was that utilization of the 8-inch would
1. Require the US Navy to have its own line of ammunition that no one else could use.
2. Surface ships would no longer have to rely on aircraft to supplament their terribly small numbers of Harpoon ASM to conduct anti-ship warfare.
3. The Mk71 would only be an evolutionary change in weapon system, not revolutionary. AGS is a DD-21/DDX/DDG-1000 weapon and always has been. It has not been meant for the fleet. The Mk71 was meant for all cruiser and destroyer sized vessels.

The Navy has gone to extensive development cost and years of maintaining a capability vacuum just so they could maybe save money down the road by having the same stuff the Army.

The mount itself is a bunch of metal arranged in a mechanical manner. The electronics are what change with the times. Modernization is no big deal.

While technological progress is necessary, sometimes the answer is something we have already produced. The Mk71 is still the best choice.

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Proper Preparation Prevents Poor Performance

I am also surprised by the consistent need for heavy volume And weight of fire but the consistent under development by the US Navy. The last time we really developed a major caliber gun was when we were actively engaged in a war that required naval gunfire support (Mk71 MCLWG). We fixed it for 12 years with battleship reactivation, but then like a bunch of morons, those in charge decommissioned the battleships...again without a replacement. Major combat since (Afghanistan and Iraq) has been outside of naval gunnery range, but that does not mean there will not be Nor has been conflict within range of the coast. Special warfare of many different kinds have called on DDGs for NGFS in the 2000s and effectiveness has been directly questioned. This is what we have been trying to prevent: confirmation in actual combat of the ineffectiveness of 5inch fire.

The Mk71 utilizing 8-inch munitions has been the answer for over 20 years. The system even comes with precision munitions.

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Proper Preparation Prevents Poor Performance

My opinion is that the AGS is a failure. Not because it will not function, but because it was far too much money spent in the wrong direction, wasting time and yielding a system that is overwhelming in size and cost for a limited gain in effect on target.

The caliber was limited to 155mm to try and enforce commonality of ammunition with the other services. This failed, as all AGS ammunition has to be developed separately, for NO cost savings in ammunition development or logistics. So it became limited by its ammunition.

So a massive amount of our tax dollars have paid for a system which cannot be mounted on anything other than new construction, fires slower than the mount it replaces or alternative mounts of a similar type, does not rectify the lack of firepower weight issue, and is saddled with a caliber which will increase cost for the development of advanced projectiles and limit the payload capacity of those projectiles.

Mk 71 mod 0 already had a higher throw weight and a higher rate of fire. It was reasonably able to retrofit to platforms with the Mk 45. The magazine was not space limiting.

All of those traits make the Mk 71 the better basis for development than what we currently have in the AGS. Keeping in mind that the Mk 71 as tested was a contemporary of the Mk 45 Mod 0/1, one can see the room for improvement as reflected by modifications of the Mk 45 to mod 4.

I believe the only way to ‘save’ the investment on the AGS is to raise the caliber, and strive to reduce the size of the mount (specifically, the magazine equipment). I do like the projected capacity of the magazine (750 rnds aboard DDG-1000).

Haha. You just called AGS a wet turd.

I have access to the US Navy's ammunition inventory system, and we still have a lot of 8" ammunition left. Following how the 16" rounds were refurbished all we would have to do is melt the Comp. D loads inside of them out and reload them. In addition to standard fuses being used again, GPS course correction fuses should be loaded into a large number of them. Oh, that's right. Making a ballistic 8" round a precision munition.

You had asked me why I said at least 3 times the weight for the same magazine capacity.

5"/54caliber round is approximately 68lbs.
8"/55caliber round is approximately 270lbs. I say "approximately" for both, because both rounds have different loads and weights to them. The SALGP presumably had a different weight as well.
270/68 = 3.97. So, I was wrong. It is more. With the gun and ammunition weight differences, the weight in the bow might be represented by a ratio of 5:1. That is going to be pretty intense, so if a significant number of rounds (600) is going to be carried up forward on new construction, the bow should be expanded if 600 rounds is to be expected aboard. Perhaps even more than what I did for the DDH.

One might then ask, "Well....if you're going add all that extra space and only have as many 8" rounds as you have 5" rounds, why not use all that space for like 4 times as many 5" rounds, huh?"

Well, the reason why is: The 5" round sucks. We only use the 5" round because we have been stuck with it, not because it's a good projectile.

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Proper Preparation Prevents Poor Performance

Guided 8" rounds is something I know nothing about. What is the guidance mechanism? Fins? Does a GPS fuse prevent the round from exploding if the GPS co-ordinates are not successfully met?

Thanks,
Bob

This is the laser guided round. This thing can loop around the opposite face of a mountain if you wanted it to. This piece of machinery with a GPS guidance instead of a laser seeker could strike opposing defilated areas without the gun having to shoot at extremely high angles. That's a really good thing.

and here is one of the data sheets on the 8" ERGM from the manufacture FMC now owned by BAE:



The other is a PGK, or the Precision Guidance Kit. It's literally a fuse replacement. A variant of this can also be used on 5" and 16" rounds. 16" rounds are already so accurate, more accurate than 155mm field artillery, so not as severe correction would be needed to align 16" rounds to meet the achieved Zone 8 accuracy, less than 50 meter dispersion with a target of 10 meters or less than the 155mm.
The fuse itself has little drag fins on it to steer the round back into target. I don't know about any kind of self destruct if that's what you mean.

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Proper Preparation Prevents Poor Performance

I was thinking more about limiting collateral damage. If the round was too far away from its target coordinates could the fuse prevent ignition (explosion)? Basically, a fail-safe. Of course, the round would still cause some damage from physical and kinetic impact but that would be orders of magnitude less than an explosion. Just wondering out loud.

Thanks for the photos. Awesome!

Regards,
Bob

That's a good question, and I think that and other details like the range of proximity fuses, net explosive weights, what kind of yield the explosives inside the rounds carry are all classified numbers. Commonsense says yes, but who knows?

I know that 5"/54 rounds and 155mm rounds in Beirut were notoriously inaccurate. A Lebanese friend of mine lived through that war and told me about the short comings of naval artillery. He also told me about how remarkable the 16” fire was and how effective it was. He said it caused earthquakes that lasted for hours. With the exception of one of New Jersey's gunfire missions, most of New Jersey’s 16" rounds landed between 50 and 70 yards of their intended target. The bad lot of propellant, however led to a recorded 600 meters inaccuracy and probably worse, and that was a real problem. Whatever you're overshooting is vulnerable, and if the fuses have a self destruct function, that would be fantastic.

Accurate or not, what I have been able to find on the net is that a 5" round has 20-30meters lethality zone. Honestly, I think that’s over estimating what the little, tiny amount of explosive a 5” round carries. An 8-inch round is recorded as being 2.5-3 times more effective (the same effect on a ship as a Harpoon), and a 16" round has a lethality zone is 300 meters. A 300 meter kill radius is the same as a 1000lb JDAM. If one is wondering why only about 500lbs of explosives in a 16” bullet can produce the same effect as a 1000lb bomb, it's because the projectile is a hardened, remarkably strong steel case that contains the explosion far longer so the explosion is more efficient and more effective, whereas aircraft dropped bombs are just a bunch of explosives that don't really react all that efficiency. As is illustrated here, a self destruct capability of any of these is greatly desirable.

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Proper Preparation Prevents Poor Performance

So BAE must have been reading my posts...(with the exception of increase in caliber)



Announced April 4, 2011:

http://www.seaairspace.org/2011/stories ... -baeb.html

http://events.us.baesystems.com/SAS/pro ... S-LITE.pdf

The initial announcement mentions targeting the new flight of DDG-51s, but the second link shows a pdf which hints at the ability to retrofit:

"Adaptability – The AGS-L system can be easily
tailored to meet the size, weight, and power
allocations of new and existing ships"

So, if this can be retrofit to the flight 1 DDG-51s, it could be placed on my refit of Flight I proposal. It may find more traction as it is more alive than the Mk 71 at this time, and ammunition commonality with the DDG-1000s.

I am curious if the capacity of 180 ready, 240+48 total really allows retention of the forward VLS. The illustration on the pdf implies retention of the VLS and the ability to retrofit to the Flight I DDG-51s, but there is no confirmation that that would be in the exact configuration mentioned in the text.

I would be tempted to trade the forward VLS for a second mount if possible - because 6 rnds/min is not terribly high..

AGS lite is supposed to weigh 51 tons, so the trade for the VLS would work based on weight : 32 cell Mk 41 with 32 SM-2 should be approx 72 tons.

From various readings around the Internet, the AGS is only credited with being able to fire the LRLAP round. NavWeaps states that the Army's 155mm rounds are not compatible. There appears to be no ASuW round, yet. Does this agree with everyone's understanding?

Also, does anyone know if the AGS will have a backup, non-GPS guidance/aiming system?

The links above indicate an "ASuWP" ballistic projectile, so it does look like there is a ballistic round available (or projected).

I imagine, at least in this application, those would be fired using the GFCS already onboard the DDG-51s.

And yes - they left compatibility with other 155mm rounds behind long ago...note BAE never makes any claim of compatibility with other 155mm rounds, but many authors assume it when they write articles.

I've been unable to find any reference to an ASuW round other than in the link you provided. I suspect that the round is a future wish-list item. If so, it makes the DDG-1000 (and DDG-51 Flt III, if so equipped) strictly a land attack platform, at least as far as the gun is concerned.

Let me know if you find anything that suggests the ASuW round currently exists.

Negative, one does not exist. It is only notional at the moment. In my investigation of the Mk71 MCLWG with United Defense (formerly FMC) I have discovered in the early 1990s the Mk71 was scaled down to about 2/3 size to a 155mm mount. It was designed and scale models built. It was dropped when the Navy decided to drop efforts to develop anything beyond the 5" ERGM. Later on, as we have seen, the Navy was forced to resume consideration of a 155mm round, because 5” just sucks so badly.

Here's a picture of the model built for the Navy Lague and Surface Navy Symposiums. I guess the inert 155mm round to the left is to only represent a conventional round but makes it look like the mount can fire it, too.


It was estimated that it would take between $200 million and $400 million dollars and 3-4 years to develop and field the 155mm/60caliber Mk71 mount. It would have been able to draw directly from NATO, US Army, and USMC inventories and fire all types of 155mm rounds (HE and Copperhead laser-guided rounds, and now includes the Excalibur GPS guided round).

Unfortunately instead of picking back up on the Mk71 they decided it was better to spend another 15 years developing another 155mm gun system that can only fire one kind of round that would have to have an entire line of ammunition developed for it...from scratch...instead of using a gun that already was in the works and was based on a proven mount.

Then the navy threw in a requirement to reduce or eliminate manning from the mount. This means everything has to be done by machine.

Here is a picture of the proposed AGS(L):

Note in the picture the crammed some VLS in the back!

So in order to fully automate a naval gun mount like this they had to make these huge 8-round blocks that maneuver around inside the magazine so they can be aligned with the hoist and loaded into the gun. This type of system makes the magazine consume it approximately 300% the internal volume and reduces capacity to about 30% of a conventional magazine. These efforts were able to reduce the ship's manning by....4-6 people.

So, now we have an AGS with an ammunition system that is so complex and large that only 133 rounds can be carried on a DDG-51 at the cost of 32 missiles. The 32 missiles is at the cost of volume, not weight. The Mk71 plus 64-cell VLS can be put up front on a DDG-51 without making it too bow heavy or lengthening the ship.

Minimal manning requirments have reduced ship’s effectiveness to minimal levels as well.

The 155mm/60caliber gun mount with the 8” length ready service loader could carry the 80+ inch long 155mm LRLAP rounds, too, making the Mk71 155mm/60caliber gun able to fire all 155mm rounds employed by the US.

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Proper Preparation Prevents Poor Performance

So, if I understand all this correctly, an AGS-Lite mounted on a Burke Flt III (or an AGS on a DDG-1000, for that matter) has no ASuW capability? A ship whose gun(s) can't engage an enemy ship? Am I missing something, here?

I don't see why you guys are trying to determine whether this yet-to-be-realized gun system can or can't use the also yet-to-be-realized surface warfare round. It seems silly to be so deterministic about something that has not been formally designed.

In other terms, why assume the AGS-L can't use anti-ship rounds? Why assume the Burke Flt. III won't have anti-ship fire control systems?

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De quoi s'agit-il?

Well, aside from the purely academic interest, the AGS is being installed on the DDG-1000 and the Navy is strongly (possibly already committed) looking at installing the AGS-Lite on the Burke Flt III. Given the aforementioned inability to operate in the ASuW role it would be a head scratcher of LCS'ian proportion.

From a modelling perspective, several of us have been designing as realistic as possible "What Ifs" (yeah, I know, a contradiction in terms) which might involve the AGS and this limitation might disqualify the AGS from those particular designs.

Beyond that, it's just bizarre! A naval gun that can't engage naval targets. What's next, a littoral combat ship that can't ... ah, never mind; this sentence can't end well.

for continuity, also partially posted in the CA name thread:

Current state of the Flight I DDG-51 refit to enhance fire support as I see it:

Hull/machinery upgrades/replacement/repair
Updating of Stacks
Retain both Phalanx (fore and aft)
Add Mk 38mod2 Port and starboard
Fwd: Mk 71 and 8 cell Mk 41(probably loaded with 32 ESSM)
Aft: 32 Mk 41 cells and Mk 71
and small hangar for RQ-8A Firescout UAVs


So - this removes 24 cells forward as weight compensation for trading Mk 45 for Mk 71, and trades half of the cells aft for an additional Mk 71. i envision the updated Mk 71 in a low-vis gunhouse, naturally (i'd prefer armored, if possible). There seems to be (by my modeler eye and walking the USS Benfold's helo deck) room to add a small hangar for UAVs/aviation weapons mag on the forward end of the deck while still retaining sufficient deckspace for H-60 operations.

What goes into the 40 cells aboard is up to debate - clearly ESSM for a unit operating close in would be important. Busto has also added the potential viability of the Mk30/31 weapon from MLRS, maybe in a quad pack. when you quad pack many of the cells - the weapon load is pretty good - like 32 ESSM, 64 Mk30/31v, and 16 SM-2/3. Tomahawk would trade with the Mk30/31v on a 1 to 4 basis.

AGS-L might be able to be fitted in place of the Mk71, but no more info on that so far.

More info on AGS lite from the vendor, which does illustrate the retention of the VLS forward:

http://www.dtic.mil/ndia/2012armaments/ ... 4weyer.pdf

180 rounds, 6 rounds per minute. Pretty slow, in my opinion. Probably not enough to really exploit MRSI. I'd really like to see 12 rpm...

Zummwalt, with the 'full' AGS is supposed to have an ROF of 10 - but that is twice as she ships two mounts.

So, math wise, you need three refit Burkes for the firepower of one Zummwalt (not addressing rather what Zummy's going to pitch is enough...)

But, it is better for fire support than the current 5"/54 due to range, and an increase in payload (200lb vs 68lb projectile).

Of course, the 12 RPM already existed in Mk 71, with a package size of 240-260lb... To bad they did not proceed with longer range 8"...