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US Navy - Problems with Freedom Class Littoral Combat Ships

FJAG

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Seems there may be huge problems with the drive train on the Freedom Class LCSs:

US Navy investigates potential LCS class-wide design flaw
By: David B. Larter

WASHINGTON — Repeated failures in the propulsion train on the Freedom-class littoral combat ships Little Rock and Detroit have raised the specter of a class-wide design flaw that could trigger an expensive reworking of a crucial component on 17 of the Navy’s small surface combatants.

The issue being investigated is whether there is a fundamental issue with the design of the Freedom-class’ combining gear — a complex transmission that connects power from two large gas turbine engines and two main propulsion diesel engines to the ship’s propulsion shafts, which propel the ship through the water with water jets.

A potential class-wide issue with the propulsion train on 17 ships either in the fleet or under contract is the latest in a long string of issues with the littoral combat ship program. Senior Navy leaders have tried repeatedly to set the program aright only to be confronted with stubborn challenges ranging from unreliable engineering plants to glacial development progress on the sensor packages that would give the ships credible warfighting capabilities.
...
The Freedom-class was designed by Lockheed Martin and built at Fincantieri’s Marinette Marine shipyard, which recently won the Navy’s next-generation frigate competition.
...

See whole article here.

:cheers:
 

FSTO

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FJAG said:
Seems there may be huge problems with the drive train on the Freedom Class LCSs:

See whole article here.

:cheers:

The LCS program was the spawn of the transformation craze which also begat the Zumwalt DDG.
No legs, modularity never worked, not enough crew.

Why do you think the USN is getting a European designed Frigate? Because they never properly replaced the OHP's.

 

NavyShooter

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I read about this earlier and observed that the root problem is the 40 knot speed requirement.  To attain that, apparently, their cross-connect gear box doesn't just rely on the gas turbine engines, but also they tie in their cruise diesel engines to sustain that speed.  The problem seems to be having the diesels in the system at the same time as the GT's.  I can see that - a couple of DGs running at ~1800 RPM connected to a gearbox that's got a pair of GT's at 23,000 RPM...the conversions internally to harness the power of those engines at different RPM rates like that would be...challenging...to make work.

NS
 

FJAG

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NavyShooter said:
I read about this earlier and observed that the root problem is the 40 knot speed requirement.  To attain that, apparently, their cross-connect gear box doesn't just rely on the gas turbine engines, but also they tie in their cruise diesel engines to sustain that speed.  The problem seems to be having the diesels in the system at the same time as the GT's.  I can see that - a couple of DGs running at ~1800 RPM connected to a gearbox that's got a pair of GT's at 23,000 RPM...the conversions internally to harness the power of those engines at different RPM rates like that would be...challenging...to make work.

NS

That's pretty much the thought. The article says the technology is feasible but that 40 knots may be on the edge of that capability.

:cheers:
 

FSTO

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NavyShooter said:
I read about this earlier and observed that the root problem is the 40 knot speed requirement.  To attain that, apparently, their cross-connect gear box doesn't just rely on the gas turbine engines, but also they tie in their cruise diesel engines to sustain that speed.  The problem seems to be having the diesels in the system at the same time as the GT's.  I can see that - a couple of DGs running at ~1800 RPM connected to a gearbox that's got a pair of GT's at 23,000 RPM...the conversions internally to harness the power of those engines at different RPM rates like that would be...challenging...to make work.

NS

Hence the no legs. To get an LCS from San Diego to Pearl Hbr the USN has to have a tanker RV with the ship half way. And that is when its at cruising speed. I cannot imagine how thirsty she'd be a 40 knots!
 

Navy_Pete

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Here's another article that shows the setup; looks like the diesel and GT both input into one single combined gear box, then output to a shaft (that splits to provide two waterjets). They have that setup duplicated for the other side.

For context, ours are an "or" setup, and the gearings are set up so that there is a speed differential that automatically disengages the associated clutch during the handover. There will be a brief period where both will be engaged, but also not at full engine power (to stop the engine that disengages from overspeeding when the clutch opens). 280s and CPFs operated under the same principle (with the 280s having two independent cruise GTs instead of one cruise diesel).

Gearing design is already a bit of black magic when you are looking at gear tooth meshing at full power with a single input; can't imagine it's easier when you are combining two inputs, no wonder it's having issues. Kind of surprised they just didn't use a bigger GT for reliability, but probably some kind of dueling requirement between speed and fuel economy.

On the plus side we learn from their expensive mistakes what to avoid, so the type 45, Zumwalt and the LCS are good lessons of where not to innovate.

https://news.usni.org/2016/02/16/littoral-combat-ship-uss-milwaukee-could-leave-for-mayport-under-propulsion-restrictions-as-soon-as-wednesday
 

Kirkhill

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Wasn't the LITTORAL ship supposed to be a COASTAL patrol ship? A sprinter based close to shore that could self-deploy occasionally? As opposed to the Blue Water ship that the surface fleet wanted - and continue to try to use it as?

Also the original spec was written off the back of the Austal experience with intermediate range catamaran ferries. Which worked. Had a large deck area. Could accommodate various loads and modules while remaining stable.

Austal produced the Spearhead class JHSVs, and the Independence class LCSs - whose contract was not curtailed.

Martin Marietta's monohulled Freedom was, IMO, an effort to secure at least part of Austal's contract by appealing to the traditionalists of the surface fleet of the USN. The result was an amphibious dromedary.

I seem to recall that the USN extended the production run of the Austal Independence class trimarans and that there is discussion of melding the LCSs with the JHSVs to use the JHSVs as MRTs for the LCS fleet. That fleet of sprinters would be used in support of the Light Amphibious Ships and the USMC's Littoral Combat Regiments.
 

CBH99

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The LCS program was the spawn of the transformation craze which also begat the Zumwalt DDG.
No legs, modularity never worked, not enough crew.

Why do you think the USN is getting a European designed Frigate? Because they never properly replaced the OHP's.
Part of their issue - which we all know - is the USN is trying to use it for something other than what it was designed for.

It’s a gas guzzler for sure. But at 40 knots, it’s easily forgivable.

The modularity should have worked. No idea why it didn’t, but the concept of each module seemed common enough.


It’s too bad it has such short legs. With an ASW fit, catamaran hull, and 40 knots if needed - and the ability to carry 2 helicopters - it could have been a very nasty ASW platform.

The ships have issues for sure. But I think the USN’s concept of operations for them makes those issues far worse.

0.02
 

Kirkhill

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... (a) Democratic lawmaker on the committee suggested the Navy should learn when to abandon a problematic shipbuilding program. Rep. Jackie Speier (D-Calif.), a longtime critic of the LCS program, criticized the Freedom variant as “terribly unreliable” and pointed to propulsion issues that have plagued the Freedom-class ships.

“I have a very different view of the Littoral Combat Ship than my colleague and I’d like to drill down on this a little bit. The Freedom-class is in my view – and in the view of many – terribly unreliable, with the Little Rock, Detroit and Sioux City all recently experiencing major propulsion failures,” Speier said during the hearing.

The Freedom-class LCS may also have a class-wide defect, a flawed combining gear that breaks early in life of the ship,” she added. “That will require massive and expensive taxpayer-funded reconstruction. In the meantime, the last administration increased the [operational tempo] to new highs.”

Lockheed Martin, which builds the Freedom-class LCSs, must fix the problem with the combining gear.


Previously I erroneously referred to "Martin Marietta" as the manufacturer of the Freedom class LCS. The ships are built for Lockheed Martin by the Marinette Marine yard of Fincantieri in Marinette Wisconsin.

Fincantieri will also be building the FREMM frigate for the USN as the Constellation class.
 

dimsum

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Fincantieri will also be building the FREMM frigate for the USN as the Constellation class.
I didn't think I'd see the day that a non-US-designed ship would win a USN shipbuilding contract.
 

Kirkhill

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I didn't think I'd see the day that a non-US-designed ship would win a USN shipbuilding contract.


Indicative of US manufacturing capacity

Reagan built most of the US hardware currently in service.

Since then, outside of the aerospace industry, the Europeans have been developing most of the new vehicle and ship designs. And the ships have largely been built in the East (either Eastern Europe or the Orient). Australia has retained its own indigenous capabilities and carved out a seagoing niche in fast, intermediate range, coastal vessels.
 
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