Littoral Combat Ships (LCS)

Jura said:

... calls for a question: will the engines be changed in "the follow-on frigates"?? if not, what will be gained by going below 40 kn, fuel saved for the cruising speed maybe?

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The primary driver for a downsized engine (which in the past I have on two separate occasions said was needed) is that the LCS design was close to its SLA. Given the planned move to a SSC/FF, something has to give. It is simple maths. The engine downsize also immediately addresses the endurance issue. Under the Adaptive Force Package (AFP), the minimum force constituent is two and if paired with a Burke, it would just hinder operations because of more frequent replenishment requirements.

This development is rather out of the blues because the first 24 ships are already locked in. The plan was to identify early changes so that some of it can incorporated to the transitionary batch of 8 in order to reduce retro fit. However all these was tied to a requirements study in terms of capability gap so that the final configuration for the last 20 (so called FF) would be bedded down.

I think if there is a engine change then it would have been mentioned some where but if they do wouldn't that mean a redesign of the engine compartments mounts etc. I smell delays and costs over runs with all the usual excuses and wouldn't they have to redesign the water jets also

“One of the ways you do that is by inserting commonality, so where we can … we’re going to make [the two frigate variants] the same, and we’re in the process of going through trade studies to figure out what exactly that means system by system, box by box.”

As a result, Brintzinghoffer said he expects much more government-furnished equipment on the frigates compared to the LCS, where prime contractors Lockheed Martin and Austal USA were given leeway to outfit the ship as they saw fit so long as the final ship design met certain mission-based requirements.

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These are problems that were self created. Having two initial design and two ship builders (due to Washington politics) and then allowing them to do their own thing. The two design don't even share a common combat system. They now have to go through the difficulties of realignment and retrofitting. It is just bad program management.

Agreed but that's what we got to work with just hope they don't mess it up worse than it already is if that's possible

My guess would be goveners would be installed thus limiting rpm thereby increasing range and decreasing speed

I guess it's also possible to reduce speed by some kind of gear reduction process but that's a lot more complex procedure and probably add even more weight

dtulsa said:

I guess it's also possible to reduce speed by some kind of gear reduction process but that's a lot more complex procedure and probably add even more weight

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I am not an engineer but my basic understanding is that when you have an engine designed for speed then the trade off is that at other speeds, the engine is likely to be less fuel efficient against an engine not designed for speed.

This is true from my experience with cars but that's never stopped our government from wasteful project's before. Just read Wikipedia article again it stated the original lcs was designed for an orderly (crew evacuation) in case of damage from battle I have never heard of such a procedure

dtulsa said:

Just read Wikipedia article again it stated the original lcs was designed for an orderly (crew evacuation) in case of damage from battle I have never heard of such a procedure

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Small warships are historically unsurvivable in combat. They have a shorter floodable length, reduced reserve buoyancy and more likely to be affected by fire and smoke damage than larger combatants. The original lcs was designed with survivability sufficient for crew evacuation and not ship recoverability.

The SSC added passive and active defence improvements to enhance survivability but in Navy terms is meant as a combination of susceptibility, vulnerability and recoverability. Understanding the issue in singular term as simply recoverability would not be tuning in on the right wavelength.

Brumby, I got more questions than answers ...

Brumby said:

The primary driver for a downsized engine (which in the past I have on two separate occasions said was needed)

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hold it right here: I've always thought the unusual hull-forms (trimaran and kinda yacht were chosen to efficiently operate the waterjets (as practically the only way to achieve the exorbitant speeds), but now you're suggesting what exactly? (unfortunately I haven't noticed the previous posts you mentioned above)
I'm heading to this: if you required just let's say 33 kn max and 13 kn cruising speed, wouldn't the traditional hull-form/propulsion be much more fuel-efficient? (but I don't know what you mean by "a downsized engine" so I hope I won't I create any confusion)

Brumby said:

is that the LCS design was close to its SLA.

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I'm sorry but the acronym finder showed me 93 items for "SLA" so I ask you to tell me what it stands for here

Brumby said:

... Under the Adaptive Force Package (AFP), the minimum force constituent is two and if paired with a Burke,

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please post a link describing "AFP"

Brumby said:

it would just hinder operations because of more frequent replenishment requirements.
...

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... and I wonder about replenishment this way:

1. I've read somewhere in Internet there are supplies for 14 days on an LCS (60? Sailors)
   

2. Jura said:

   ... "the follow-on frigates" ... their complement would exceed 100 Sailors

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if both 1. and 2. were true, how long deployments without replenishing would it mean?

Very good question seems as confused as ever maybe convert some space that was used for module's to berths and supplies I guess it's giving me a headache already

LCS get an inferior range as Perry at cruise speed obviously Perry 4500/20 kn, Freedom 3500/18 and Independence more big almost as Perry 4300/18.
In general a combat ship carry about 10 % of her full displacement in fuel.