Skip to content

LCS Alternative-Diesel/Electric Corvettes

July 20, 2009
Sweden's Visby corvette is Meyer's ideal platfrom for a d/e corvette design.

Sweden's Visby corvette is Meyer's ideal platform for a d/e corvette design.

I defer to Mr. Carlton Meyer to explain this intriguing concept:

Surprisingly, no navy has constructed a DE ship that can switch to quiet electric propulsion when hunting submarines.  This does not require the development of new technology, DE engines already exist on submarines.  A small ship is best for submarine hunting as they are quieter, harder to see on the surface, more maneuverable, and a smaller target for submarines.  While cruising slowly on electric power, a DE ship will produce no heat for detection at night or in poor daytime weather, which submarines may detect with infrared periscopes.  A DE corvette is an ideal size for a sub hunter, with a displacement of less than 1000 tons and a submarine hunting helicopter on board…
       DE corvettes will also prove very effective in port defense, prowling silently on electric power while searching for small boats or anything along the shoreline indicating naval commando activity.  Silent DE corvettes are perfect for amphibious and special operations.  At nightfall or in fog, they can switch to electric to go silent and cold and come slowly over the horizon to the shore to pick-up or drop off reconnaissance or commando teams, then depart back over the horizon to safety.

This would get a hard reception within traditional naval circles, since it would be such a stealthy and lethal surface killer, the admirals would likely see it a threat to their battleship programs! Leave it to China then? And as we always insist, the corvette needs a mothership to make up for its lack of endurance:

If a navy plans to conduct expeditionary or amphibious operations, it will need to deploy DE corvettes and sustain them in remote locations.  Small ships are difficult to maintain forward-deployed since they lack much of the organic maintenance support and crew comforts of larger ships.  Therefore, corvette squadrons need tenders, like the recently retired Yellowstone Class AD- 41 destroyer tender. (below)  A deployed squadron needs two tenders to keep one on station while the other journeys to a distant port for replenishment.  The squadron headquarters will remain embarked on the deployed tender, which will remain at sea with larger warships in high-threat environments, or in low-threat areas it may drop anchor in a small cove at an offshore island, although it may move every few days depending on the enemy threat.

Here then is the answer to the Navy’s “presence deficit”. Without a requirement for huge fuel and ammo stockpiles, small warships could be built which would cost far less than modern battleships like the Arleigh Burke class. Yet such craft will not have to sacrifice firepower for endurance as does the LCS. The mothership could also embark the squadron’s essential aviation assets like helicopters and UAVs, further easing  the load on her brood of naval “fighters”.

Taking a jab at the LCS, here is Meyer’s reason why it is a flawed, failed design, with which we concur:

Look at all the other modern coastal ships around the world to discover the LCS is twice their size.  Twice the size means twice the target and twice the cost, all this for high speed?  The LCS is the size of modern frigates and bigger than destroyers of World War II, yet has the armament of a patrol boat in order to accommodate the mysterious ultra high-speed requirement.

Makes plenty sense. Anyone in Washington listening?

lcspriceless

38 Comments leave one →
  1. Mike Burleson permalink*
    January 4, 2010 8:51 am

    Carmen, your feedback is always welcome at any time. All comments come right to me no matter the age of the posts.

  2. January 4, 2010 7:50 am

    My feedback might come a bit late but I really enjoyed this article and discussions. Very educational! We were just discussing DE propulsion on another website :)

  3. Mike Burleson permalink*
    July 23, 2009 5:22 am

    Obviously with what’s been ongoing in the China seas, TAGOS is vulnerable to surface threats. Has anyone ever considered arming these ships? There’s your d/e corvette! At least something closer in size to the older Stalwarts because you don’t need the long range.

  4. Grandpa Bluewater permalink
    July 22, 2009 9:54 pm

    A few points about TAGOS:

    My comments will be about the older monohull design, unless specifically stated. The catamarans are highly specialized, not a viable warship design.

    The ship has a towed array, no hull mounted sonar. The hydrophones are a very long way from the ship.

    A single prototype sound isolated diesel was tested on a single Guppy (Guppies….Greater underwater propulsion power – the y was merely cute – were extensively modified wwII Tench class submarines brought up to basically the same submerged speed and endurance baseline as the German type 21’s). It worked fine, but the early 60’s nuke plants worked better. So sound isolating diesels were ever pursued further, sound isolation tech went into nuke engine room design. Some of that got fed back into TAGOS machinery vibration isolation on a much less ambitious scale, I think.

    The design had a small propulsion plant because the ship needed range and endurance on station, not speed. Diesel generators powering the electric motors turning the shafts gave relatively quick response to bridge controls and a thruster in the bow, and powered a huge cable winch. There was absolutely no requirement for speed when on station. It was a good design which did what it was supposed to reliably and economically and required a very small crew. The hull form was more optimized for stability in rough water, i.e, sea keeping.

    You can put a lot of sound isolation around a much bigger plant, with a much finer hull form in a TAGOS sized hull. You can get a much faster ship.

    Or scale it up a bit and get a post Korean war sized DE. It will have a huge battery compartment (or two) low in the ship and midships, And all the headaches that come with it. Plus all the headaches that come with big diesel generators and electric propulsion motors.

    Not cheap, not easy, and needing its own unique logistic support. As usual. TANSTAAFL.

  5. Scott B. permalink
    July 21, 2009 8:12 pm

    Navark said : “However, the original article seems to be suggesting an auxiliary DE system as found in submarines, although fails to mention that the noise and vibe reduction is accomplished through using the extensive battery bank – I’ve never come across such a system in a surface ship…”

    Hodge & Mattick in their “Electric Waship” saga (article #1 in 1996 to article #6 in 2001) have repeatedly suggested the use of an Energy Storage Device in their proposed electric ship power system.

    In the first article (1996), this Energy Storage Device was a traditional lead acid battery widely used in submarines. For a 4,500-ton monohull frigate, the battery was supposed to supply a typical action load and propel the ship at a maximum of 12 knots for 30 minutes. The battery’s volume was 37 m^3 and its weight was 118 tons (i.e. 2.6% of lightship displacement).

    In the last article (2001), *suitable* technologies listed for this Energy Storage Device included traditional lead acid batteries, advanced batteries (e.g. Zebra), flywheels and Regensis system. In this article, the authors conceded that “the need [for Energy Storage] must be judged against the application and be tailored to the specific system requirements.”

    In the presentation they made last year in Germany, they timidly mentioned “some measure of localised zonal energy storage” as part of their new Electric Warship Vision.

  6. navark permalink
    July 21, 2009 6:44 pm

    Scott B. – The weight penalty of IFEP or any diesel generator/electric motor on small vessels is a major handicap, the 6% weight penalty you refer to is for a low power slow ship.

    For the fast corvette that others are talking about, I would expect the weight penalty to be far greater, possibly up to a 20% increase in displacement for a high power installation including gas turbine/generator sets and the corresponding large electric motors.

    However, the original article seems to be suggesting an auxiliary DE system as found in submarines, although fails to mention that the noise and vibe reduction is accomplished through using the extensive battery bank – I’ve never come across such a system in a surface ship…

  7. Heretic permalink
    July 21, 2009 4:33 pm

    How does it even know its in range of a land-based launcher?

    Unless there is over the horizon radar in play, the curvature of the earth provides a pretty good measure of whether or not you are “in range” of a land based launcher … since coastlines tend to be mapped, and by definition, any land based launcher would have to be on land.

    I would note that this concern is already codified by the 25 nmi “exclusion zone” around every coastline in the world that the biggest blue water navy in the world is bound and determined to concede without firing a shot.

  8. Mike Burleson permalink*
    July 21, 2009 1:30 pm

    “Mike, how does a corvette outrun a fixed wing aircraft or helo?”

    Again, I concede that all warships are vulnerable in such waters. The corvette can beat these weapons as far as range, but nothing is certain in warfare. Even if you’re right that the large warship is more survivable, what you lose with lack of numbers and presence deficit, takes away from this advantage.

    What is certain is that there are parameters where some vessels are more capable than others. The large ships have their blue water domain, and the small are best suited for coastal operations. In their respective environments, one is more survivable than the other.

    Nothing is invincible so better to have many smaller ships with many separate weapons launchers, than a few Big Ships with many weapons launchers, which is redundancy considering the accuracy of precision weapons. With the corvettes and the new precision weapons, you get numbers and capabilites (smart bombs+the dumb or spartan platform).

  9. Scott B. permalink
    July 21, 2009 1:11 pm

    I am surprised to see that none of the regulars from UK injected at least a brief comment on RV Triton into the discussion…

    Anyway, acoustic signature was a major design consideration for RV which featured an integrated propulsion plant comprising two Paxman 12VP185 2MW diesel generators and two 350kW electric side thrusters with a single central screw (with a thick-bladed composite propeller to reduce vibration).

    Beyond the actual reduction of the acoustic signature, what’s interesting with RV Triton is the magnitude of the *weight penalty* of 60+ tons inherent in the diesel-electric configuration, i.e. over 6% of lightship displacement.

    (In the case of Triton, this *weight penalty* is partially offset by the trimaran hull which allows RV Triton to achieve a speed of 20 knots with 4MW where a 600-ton displacement monohull would need about 5MW.)

  10. Bill permalink
    July 21, 2009 12:11 pm

    “whats up with superconductive motors?”

    The current development emphasis is on high power-density compact digitally commutated permanent magnet motors/generators that operate with very high DC buss voltages. Up to 4 mw protoype systems are being tested, with larger under development, and they are starting to look good for some small-ship applications. Very flexible and eliminate a lot of the traditional aggravations associated with gearboxes and shaft lines. Their cooling requirements are not insignifcant…though certainly less than current superconducting technology would be.

  11. B.Smitty permalink
    July 21, 2009 11:50 am

    Mike, how does a corvette outrun a fixed wing aircraft or helo? How does it even know its in range of a land-based launcher?

    How does it find the launcher for a first strike? Its eyes are limited to LOS sensors; short-range, very limited payload UxVs; and MAYBE a small helo.

    I think it’s incorrect to assume small ships are more survivable than large ones. Large warships with high-end, long-ranged AAW suites can support one another and have a chance to shoot the archer (not just the arrow). Corvettes with point defenses don’t. The number of hits a cost-equivalent group of corvettes can take may be higher than a group of destroyers, and the capability dropoff curve may be less abrupt, but taking hits is only one part of the salvo model. Defending against them is another.

    I can see using Streetfighters (aka small, swarming corvettes) to aid in specific aspects of the A2/AD takedown, such as MIW, ASW, and small craft ASuW. They can’t provide overland ISR necessary to hunt for mobile missile launchers. They can’t provide area air and ABM defense. They can barely defend themselves from air attack. They can only contribute in a limited fashion to strike missions.

    Their logistics motherships will be vulnerable to attack by the same assets the Streetfigters (presumably) can “hide” from. And if you take out the motherships, it’s only a matter of days before the Streetfighters have to run for a friendly port.

    To be useful at all vs China or another neer-peer, they will need to be part of an overall system encompassing national ISR assets, traditional airpower (carrier and/or land based), submarines, larger surface combatants for AAW and ABM defenses, and so on.

  12. Mike Burleson permalink*
    July 21, 2009 7:41 am

    Hudson said “As for being a big fat juicy target, radar can track a beachball, which includes your nifty little corvette.”

    I agree completely. I think all ships are at risk from modern smart weapons. The advantages of the corvette is with numbers you can ensure something survives the initial missile exchange, rather than the handful of Big Ships which we think the more armor or defenses will save us. Their small size and maneuverability will also enhance survivability.

    Someone also said earlier that a fast corvette can’t outrun a cruise missile. True, but it can out run the missile launcher, or at least hide from it, perhap even get in a first strike. You want stealth? We got stealth in a 1000 ton more or less, package, and it won’t take a decade to build, or a breakthrough in technology, or a fighter jet-like competition because you can buy existing designs.

  13. Defiant permalink
    July 21, 2009 6:05 am

    whats up with superconductive motors? that stuff may be lighter (or more power at the same size) but there’s still no superconductor above -150°C, so that stuff needs to be cooled (adding extra systems with extra maintenance and more stuff that can break), moreover superconductors are fragile which is not really suitable for military use (yet). oh and the price …

  14. Diesel permalink
    July 21, 2009 1:23 am

    The French Mistrals have Diesel/Generators and two Azipods.

    I think the issue up till recently was the size of the E-motor. Submarines have huge ones, no way to integrate those into anything but SWATH-designs (using an horizontal arrangement with gearbox would be pointless). Superconductive E-motors will change that (if they work).

    The industry seems very conservative here, prefers to build supercomplex gearboxes and long shafts, like on LCS-1. I think the evolution has to start from the propulsor end, with things like the GD RimJet.

    Regarding the power generation side, I’m not sure if all things considered large diesels are “better” than multiple gas turbine/generator sets. But that is not my field, so …

  15. Hudson permalink
    July 21, 2009 1:19 am

    Playing devil’s advocate for a moment, think of the LCS as a mother ship. With its cavernous interior, it can launch/retrieve choppers, UAVs, rigid inflatables, Seal teams, undersea robots, bots of the future—and have room for crew comfort (tennis, anyone?). Don’t think the Navy won’t pitch the LCS as THE ship to serve aboard.

    It isn’t designed to stand offshore and trade heavy blows with shore batteries, if anyone makes shore batteries anymore. Its 57mm gun can shred a variety of targets with sophisticated pattern fire out to nine miles; and with NLOS as part of its surface package, it will have over-the-horizon strike capability. It could tow guntubs or heavy duty bots to do the dirty work close inshore. Or call in an air strike. Plus it has dash speed to leave the battlespace pronto.

    As for being a big fat juicy target, radar can track a beachball, which includes your nifty little corvette. The way the LCS is built, it has some blowout possibility and thus might survive a cruise missile hit.

    Though initially about as expensive as a good size frigate, its small crew will save money over the long haul. It can hunt subs, chase pirates, trail N. Korean freighters, show the flag. It’s a design that will improve as the Navy develops it, which admittedly, is slowly.

  16. July 20, 2009 10:38 pm

    @Mike: High speeds create supercavitation (very loud) at the screws. This worsens the closer the screws are to the surface (lower water pressure), so surface ship have this phenomenon at much lower speeds than subs.

    “1) Lürssen has made some high-level presentations on an all-electric corvette-sized littoral combatant here and there.”

    Well, I know only one Lürssen proposal like that, and that was not corvette-sized at all. It was their idea of a future frigate, and it was called FDZ 2020 – Fregatte der Zukunft 2020 (frigate of the future 2020)
    http://www.janes.com/articles/International-Defence-Review-2000/Germany-studies-future-frigate-concept.html

    It had furthermore no “littoral” emphasis at all.

  17. Mike Burleson permalink*
    July 20, 2009 9:01 pm

    Before everyone was saying speed is not an issue for patrol work, but now suddenly it is for the D/E corvette? The Germans get 20 knots submerged on batteries for their older 1500 ton Type 212 sub. I imagine in “silent running” the slower the speed the better for a corvette, and this held true for the old PT boats as well. The faster you go the more hull noise you make, I don’t care how quiet your engines are.

  18. July 20, 2009 8:51 pm

    Geez. WWII destroyer escorts of the Buckley and Rudderow classes were turbo-electric drive (using steam) and the Edsall, Evarts and Cannon classes used diesels. All were rated at 21-24 knots, but could go considerably faster in a pinch.

    I think we could – with upgraded technology – generate the additional SHP to get 30+ knots.

  19. Scott B. permalink
    July 20, 2009 8:47 pm

    B. Smitty said : “Where are the small, corvette-sized vessels that use it, and can they make 30+kts?”

    Short answer : there is none.

    To add some (very limited) information :

    1) Lürssen has made some high-level presentations on an all-electric corvette-sized littoral combatant here and there.

    2) One of the things they put forward in these presentations is the experience they’ve gained with their Limitless, which was the first yacht with diesel-electric propulsion and is about the same size as a corvette.

  20. Scott B. permalink
    July 20, 2009 8:05 pm

    Bill said : “The only hydrogen fuel cell vessel that I’m aware of is the German (EU funded) Zemship ferry.”

    Back in 1999, there was also a project to use USCGC Vindicator (WMEC-3, formerly T-AGOS-3, presently NOAAS Hi’ialakai) as a test ship for a Molten Carbonate Fuel Cell Demonstrator.

  21. B.Smitty permalink
    July 20, 2009 7:16 pm

    Note that USNS Stalwart is 2500 tonnes and makes a whopping 11 kts. USNS Impeccable is 5300 tonnes and makes 12 kts.

    Where are the small, corvette-sized vessels that use it, and can they make 30+kts?

  22. Mike Burleson permalink*
    July 20, 2009 7:10 pm

    Scotts right: USNS Stalwart-4 x Caterpillar diesel-electric engines, two shafts, 1,600 hp

    Any further info on these, anyone? Opinions?

  23. July 20, 2009 5:46 pm

    I’m reading and smilin. Traditional naval vessels using DE, whether surface or submarine, is a nice step towards something even “better” (my own choice of wording there).
    About weight….today’s superconducting materials allow electric engines to be much lighter than old copper wound engines. That weight savings translates into a good tech.
    As demonstrated by an Aussie company (SolarSailor), marrying solar cells to diesels….

    ’tis the same tech that we will be using on the airships. Of course, they already have no sonar sig at all….

  24. Scott B. permalink
    July 20, 2009 5:36 pm

    Mike Burleson said : “This would get a hard reception within traditional naval circles”

    Diesel-electric power has been used on every single Ocean Surveillance Ship since USNS Stalwart (T-AGOS-1), and was chosen specifically to minimize the amount of own-ship’s noise during surveillance operations.

  25. Heretic permalink
    July 20, 2009 4:18 pm

    B.Smitty said: My guess is no, and for good reason.

    My guess is no, because no one’s ever written a requirement for it before to find out it it’d be a good idea or have advantages that no one’s been looking to find before. Consider that it wasn’t until recently that trying to reduce the radar signature of a ship was even a consideration, let alone such things as thermal signature and magnetic signature (unless minesweeping) and so on.

    As for fuel cells vs combustion (and the attendant L-H2/L-Ox fuel requirements), it does need to be pointed out that for submarines the oxygen needs to be tanked on board along with the hydrogen. This basically means that you have about a 9:1 weight ratio of oxygen/hydrogen tankage. A surface ship doesn’t need to store oxygen though … there’s plenty of it floating around above the waterline … which means that *relative* to a submarine there’s “more room” for hydrogen tankage aboard a surface ship.

    That said, I’m thinking that in circumstances where combined weight+volume+fuel of the entire system is concerned, the stirling cycle engine will probably be superior to all others for a surface ship … simply because it is very compact, can be used at all times to augment housekeeping power requirements (should that be necessary, on an All Electric Ship), and it runs off the same fuel as diesel and gas turbine engines (meaning no bifurcated fuel storage engineering necessary).

  26. July 20, 2009 3:34 pm

    former Marine Carlton Meyers? friend of Mike Sparks? hmmm…..

  27. B.Smitty permalink
    July 20, 2009 3:11 pm

    Sven,

    I’m not talking about ancient battleships or WWII destroyer escorts either.

    Has CODLAG or full IEP ever been applied successfully to a small corvette (let alone a very small 600 tonne one like Visby)? My guess is no, and for good reason.

  28. July 20, 2009 3:11 pm

    DE drive is a highly efficient and flexible propulsion system. US submarines during the 1930s piggybacked on commercial locomotive technology, which matured conveniently for use on the WWII fleet boats that had such range and endurance in the Pacific war. The post-war Guppy II upgrades eliminated the reduction gears entirely and went to low-speed direct-drive electric motors, which eliminated much of the mechanical noise. Direct-drive was retained in the later Tang and Barbel classes of DE submarines.

    As to the radiated signature of the diesels, an example: on the FFG-7 class frigates, ship service power is provided by 4 diesel generator sets. This was 1970s technology, mind you, but the diesels were well isolated from the ship’s structure and highly enclosed, which reduced the overall radiated noise to a minimum, particularly when combined with Prairie-Masker and masker emitters for the screws.

    Combine all of this with improved battery technology and you have the makings of a formidable patrol/escort vessel that has the ability both to creep and dash with stealth. And all of it is available off the shelf.

  29. Scott B. permalink
    July 20, 2009 2:41 pm

    Mike Burleson said : “I defer to Mr. Carlton Meyer to explain this intriguing concept:”

    In the 1970s, a much-despised technocrat like D.K. Brown suggested the use of a quiet diesel-electric powerplant as a way to silence a ship at a reasonable cost.

    People who feel strong enough to absorb some technocratic litterature might want to check Brown’s “Rebuilding the Royal Navy” or his “Future British Surface Fleet”.

    Then the Royal Navy introduced electric drive in the Type 23 frigates.

    Now the French / Italian are following a similar route with their FREMMs, the Germans are following a similar route with their F125s,…

  30. July 20, 2009 2:35 pm

    Smitty, this blog post isn’t (in my opinion) about simple DE propulsion as in early 1900’s battleships or WW2 destroyer escorts.

    It’s (imho) about diesel-electric drives like in subs, where the ship can move silently on battery power without the diesel running.

  31. Bill permalink
    July 20, 2009 2:34 pm

    The only hydrogen fuel cell vessel that I’m aware of is the German (EU funded) Zemship ferry. 100 pax, slow, (2 x48KW power units)….and supposedly funded to the tune of over 2.5 million euros to build and operate…as compared to about 400-500K euros for same boat with an efficient little 100 KW turbo-diesel.

  32. WTH permalink
    July 20, 2009 2:28 pm

    http://en.wikipedia.org/wiki/CODLAG

    Diesel Electric is nothing new, batteries/fuel cells are a lot of weight to carry around if they’re not needed all the time.

    Properly sound insulated/isolated diesels can be darn near silent to SONAR. A lot of noise comes from mechanical drive train and hullform.

  33. B.Smitty permalink
    July 20, 2009 2:23 pm

    Sven,

    To date, DE propulsion on surface ships has been limited to much larger vessels.

    Are you proposing two completely separate drive systems then? One for slow and silent and one for fast and loud? That sounds heavy and voluminous. Remember, there’s not much room on a 600 tonne combatant.

  34. July 20, 2009 1:52 pm

    “large and heavy DE system”. Why large and heavy?
    A quiet cruise is slow – it’s not the same pace as on a real cruise, it’s rather (necessarily) at a pace of less than 10 kts. Even huge ships need surprisingly little power to sustain such a speed.
    Look at the type XXI sub for comparison: 6 kts silent cruise electric engines with only 450 PS @ 2,100 mt. The electric systems (sensors, communications, living quality) of a corvette or frigate can have a greater power requirement than that!

    Small power requirement = small and light machines.

    Mike; current fuel cells usually run on hydrogen, and that’s probably the reason why they’re limited in their applications so far. I know of no surface combatant with a fuel cell drive, but I suspect there are some demonstrator boats in service – and of course the Typ 212/214 sub classes.

  35. B.Smitty permalink
    July 20, 2009 1:24 pm

    An “ideal size for a sub hunter”? How does he come up with that? Extensive simulation using realistic threat and sensor models? Somehow, I doubt that.

    IIRC, Leesea said the US tender replacement was estimated to cost almost a billion dollars each. How does this impact the overall number of “DE corvettes” you can buy? Deploy?

    Is it really a good idea to put all of your helos in one basket (especially a non-combatant tender)?

    How much space and payload weight will be left on this small ship once you fit the large and heavy DE system?

  36. Mike Burleson permalink
    July 20, 2009 12:19 pm

    Sven, any surface ships currently operating fuel cells that you know of?

  37. July 20, 2009 12:09 pm

    A diesel-electric drive (albeit possibly part of the recent all-electric ship initiatives) is not necessary for acoustic stealth.

    I wrote it before and repeat it:
    It is easily feasible to power the electric systems of a warship and to propel the ship at 4-5 kts with a very silent Stirling engine (as in the AIP module of the new Swedish SSK).

    Fuel cells (if advanced enough by the automotive sector) are also an option.

Trackbacks

  1. Corvettes Versus Midget Subs « New Wars

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: