Stuart on the LCS, DDG-1000 and Nuclear Hydrofoil BBs

[MKSheppard]

From
Lil Crappy Ship 4 Terminated on the other board:

It all started off with a guy called Wayne Hughes who proposed what he called "rebalancing" of the fleet, essentially replacing our existing force of combatants with a larger number of small craft. Esentially he was proposing the sort of FAC-M fleet that had already been discredited in the past. Boiled down to its simplest, what Hughes was suggesting was that future naval battles would consist of a single exchange of missiles. Any ship that was fired on would be hit and any ship that was hit would be sunk. Therefore what mattered was to have more ships than the other side so that some would be left afloat at the end of that single exchange.

In reality what this meant was that instead of defending ships we should assume that they and their crews would be obliterated and accept the casualties involved. His theories weren't taken that seriously and he got little attention until he teamed up with a guy called Cebrowski.

Cebrowski had taken over as the head of the Naval War College and wanted to make his name. He picked up on Hughes' theories and created a concept called Streetfighter. This was a 300 ton surface combatant capable of 60+ knots and armed with 8 anti-ship missiles etc etc. He then staged a series of war games that showed the Streetfighter devastating its opponent. That wasn't surprising, the rules were that any ship fired upon by a Streetfighter would be sunk while the speed of the Streetfighter would prevent it being engaged effectively.

When other simulations showed the Streetfighters being slaughtered by real warships under real conditions, he started a screaming campaign in the press, the usual nonsense about how his forward-thinking ideas were being suppressed by hide-bound admirals etc etc etc etc etc etc etc. He also came up with another idea to back up Streetfighter, a small aircraft carrier displacing 3,000 tons, capable of 60 knots also and equipped with an air group of 20 F-35Cs and 10 SH-60Js. Anothers eries of games showed this also devastating the opposition.

The fact that the largest conceivable hull buildable on 3,000 tons couldn't even carry that many aircraft let alone operate them was neither here nor there.

Anyway, the whole Streetfighter concept got very popular with naval cadets, primarily because a fleet of small craft offers command opportunities at a much lower rank. Congresscritters got hold of the idea and started to press for Streetfighter construction.

That's when LCS got into the world (LCS standing for Let's Castrate Streetfighter). It proposed a radical small surface combatant (intitally 500 - 1,000 tons) with a target speed to 50 plus knots. Various shipbuilders were asked what they could provide to meet that spec. There was much tooing and froing and much confused questioning, the Navy took a look at what it was offered (basically a PT boat), vomited in horror and laid down a decent spec. The contractors took one look at the spec and passed out with shock. After the administration of smelling salts and a liitle brandy, they chorused "You have got to be kidding".

The new spec was essentially that of a frigate, essentially a faster version of the FFG-7. So, LCS went up in size to frigate dimensions (roughly 4,000 tons) and the speed went down to more normal levels. That's what is being built now.

The whole point is not to build small combatants, they can't defend themselves, lack range and seakeeping and are damned uncomfortable for the crews. So LCS has already suceeded; Streetfighter has been forgotten, people have moved on to other things now, with a little luck, LCS can be cancelled.

Hang on; why do these people need a fleet of super-fast boats?

I have been asking that question (at a variety of high levels) for ten years and I have never, repeat never, had a sensible answer. The nearest I have had was (from one female U.S. Navy officer) was that standing on the bridge wings at 60 knots would help dry her hair after a shower.

In the LCS program, the need for speed is a demonstrated end in itself. You're not supposed to ask why.

How useful are (The Pegasus Class PHMs) compared to LCS?

The Pegasus class were a truly horrible experience and they probably did more to kill off the idea of a hydrofoil surface combatant than any other consideration. They were very badly armed indeed; their 76mm gun was wildly inaccurate due to pounding and vibration and jammed like cray for the same reasons. The ships had virtually a zero sensor fit - they had a navigation radar and a fire control set and that was virtually that. So their ability to shoot their main weapons was severely restricted. They were appallingly expensive to run since they basically had two speeds, up to 12 knots or 48 knots and nothing in between. (The reason for that was that they required a specific speed to get up on their foils and that was that). So, they either allowed around doing nothing very much or ran around flat out and drained their gas tanks. Their operational range was very limited and they were utterly defenseless against air attack. They share that with all FAC-M; a helicopter gunship is a devastating weapon against such craft.

(Tale from the crypt for you. During Operation Desert Storm, the Iraqis tried to use Boston Whalers to infiltrate special forces behind coalition lines. The craft were intercepted by British Lynx helicopters which blasted their escort of FAC-M out of the water and forced to shelter in a bay.All sorts of helicopters turned up to join in the fun, mostly troop carriers using machine guns and grenade launchers out of the doors, but one ASW Sea King arrived and, lacking any other offensive weaponry, started trying to use its dipping sonar as a wrecking ball.)

The weaknesses of the whole FAC-M concept come from two things, both size-linked. One is that they lack the space to arrange tehir electronics properly. Some time ago, the company I worked then for did a study on the electronics fit of TNC-45 and TNC-62 class FAC-M. These ships are identical except the 45s have a 45 meter long hull and the 62s have a 62 meter hull. The radar/EW fits are identical - yet the TNC-62 outperformed the smaller ship across the board (when I say the equipment was identical, I mean they were exact clones - the manufacturers's serial numbers were consecutive). The reason why the difference in performance existed was quite simple; the bigger hull gave more potentially optimum positions for the antennas and reduced electronic interference.

The other weakness of the FAC-M is that internally, they are so compressed that all the ship's vital functions are essentially in the same place. Any sort of damage anywhere and a lot of vital functions go bye-bye. That's why Sea Skua is so effective despite its small warhead - even the small bang does a lot of vital systems damage.

There's many other reaosns why small craft are bad ideas (their inability to handle rough weather for example, severe on-board vibration and the proximity of the radars to the water resulting in multi-pathing for example) but overall, they're bad news. The final nail in the coffin of the Pegasus class was that they were very expensive to maintain as well as run - their foils needed frequent replacement due to water erosion and they were very prone to docking damage.

Note that when it was first announced LCS was also a mere 1,000 tons, it’s now nearly quadrupled in size!

Naturally —to accomodate more subcontractors.

It didn't quadruple in size to accomodate the EEEVIL Military Industrial complex™.

It quadrupled in size because it was the only way of actually coming somewhat near accomplishing the contradictory goals set forth by the Navy:

1.) It must be fast.
2.) It must have a sorta decent range.
3.) It must be armed with something more powerful than a machine gun.
4.) It must be capable of supporting a helicopter.

etc

And this defeats the observation... how, exactly?

Your observation was that the reason LCS quadrupled in size was to accomodate more subcontractors - ie, more military pork barrelling.

May I suggest you do some research?

Obviously something capable of reaching 40+ knots and yet being heavily armed, etc is going to have to be gas turbine powered; for simple reasons of weight. It takes about oh, 49,000~ or so HP to get a 600~ ton ship with dimensions about 25% bigger than the Asheville PGs: (206 x 30 x 11.8 ft) up to 40 knots, and 84,000 SHP to get it up to 45 kts.

Now, you might say that these HP requirements are for a traditional displacement hull, and not for a high speed planing hull. One of the early design proposals for LCS put forth was for a really really BIG planing hull type of warship; which was based off a 1980s UK design. Unfortunately, the UK design was a deliberate fraud. Stuart will be able to tell you more about this.

So suffice to say, we can't do a planing hull, so we need 49-84k SHP. (actually 100k SHP due to 20% margin needed).

Because this is a USN ship, we can't just get around with one really big engine, because of battle damage requirements; so we need to have two engines; each with a rated power of about 50,000 SHP.

Something that meets our requirement is the GE LM6000 Marine Gas Turbine Link to it.

Since we need to have a 1000 nm range at 40 knots, that comes down to 25 hours of full power. We know from that page that the SFC is 0.329 lb/per shp-hour.

So 100,000 SHP * 25 hours = 2,500,000 shp-hours. At 0.329 lb/shp-hr SFC; that means....822,500 lbs, or 411.25 tons of fuel will be needed.

So what this means is that the original spec for LCS is going to need to be 68% fuel by weight to meet the goals for hi speed running. You can reduce the SHP needed by lengthening the hull to get a higher hull speed; but this adds more tonnage, etc; and then add in the demands for a armament, supporting a helicopter, etc; and you can see easily how a 500-600 ton boat quadrupled in size to a 2,500 ton frigate before it was acceptable to the US Navy's General Board Specifications.

The problem with that non-argument is that the ships, as they are, are pretty much worthless for anything. A boondoggle is a boondoggle is a boondoggle, whether it's a billion or 10 billion or 50 billion spent on the goddamned thing.

Patrick, this isn't the point Mark was addressing. Remember, I also regard the LCS as being a criminal waste of money but that wasn't the issue being raised. The primary concern was why LCS went from 300 to 4,000 tons.

It had nothing to do with providing more room for subcontractors. What happened was that the Navy finally got control of the project - previously it had been driven by a handful of fanatics, some supporters in the media and a group of gullible politicians. When the Navy got control of it, the first thing they did was lay down a series of specifications. They demanded range figures, payload, crew levels, sensor outfits etc etc etc. All of these are things that had to be defined before the ship could be designed.

What Mark showed you - very well if I may say so - was how unrealistic it was to fit those specifications into the originally-proposed hull. It wasn't that the ship grew per se, it was that the Streetfighter supporters had dramatically understated the size of vessel needed to support the claims they were making. Put another way, LCS didn't grow from 300 tons to 4,000, it was always a 4,000 ton ship, it was just that Cebrowski-Wayne et al knocked a zero of the displacement for public consumption.

That doesn't change the fact that the thing is a boondoggle, but it does tell us that there were sound design reasons for the apparent growth in ship size. Mark gave you one very good, well-argued example of that.

By the way, another thing that went wrong with LCS was that the Lockheed Martin proposal used a composite hull to save weight. I told them that was a bad idea but they wouldn't listen. Then a Norwegian minehunter, the Orkla, caught fire and burned out. In eight minutes (eight!!!) she went from an intact ship to a sinking hulk. When the wreck was examined, it was shown that the composite hull was delaminating and that all the other members of the class had the same problem. L-M were given a choice, build the ship out of steel or forget we gave you a contract.
That pushed the displacement up by over 750 tons alone and the cost ramped skywards.

I got schooled there, but then wouldn't it be better to have dedicated helicopter carriers for economies of scale? The Iwo Jima series apparently carries 20 helos per ship, that's a helo for every 1,000 tons of displacement roughly; an LCS would carry one per 4,000 ton displacement, and that's not even counting the different types the larger ship. In addition, Iwo Jima is presumably a larger, slower and therefore probably safer platform for helos. I don't think LCS is not going to be backed up by heavier forces a few miles offshore in any case. How would you land a helo on a hard-manoeuvering 40-knot speedboat in a hostile littoral environment anyway?

This is a complicated question; on one side of the ledger, you're quite right, economy of scale suggests that a large helicopter carrier offers significant advantages over smaller ships. This is the approach adopted by the Japanese Navy with their new DDH, the Hyuga. The Thai Navy adopted a similar logic with their helicopter carrier, the Chakkrinareubet. There, the idea was to provide maritime law enforcement helicopter cover out of range of land bases. The requirement was to have two helos airborne at all times, working backwards that gave a group of around ten birds.

On the other hand, the problem with the larger dedicated helicopter carrier is that it isn't always there when its needed; the shipboard helicopter is a hard-worked piece of kit and the ships can't always rely on having a helo carrier in support. The only helo a destroyer can rely on is the one it carried itself, so there's a good case for that as well.

You're quite right on the safety aspects, trying to bring a helo in on an LCS doing 40 knots is an interesting thing to contemplate. That's one reason why I think that the whole LCS program is fundamentally misconceived; many of the things the ship is supposed to do can't be done at 40+ knots.

Another problem (just to add to the general air of gloom and despondancy) is that LCS is supposed to work within a network of sensors and can thus economize on the on-ship sensors (note that the provision of the sensor net is not included in the cost of the LCS itself). That sensor net is a horrible glaring weakness that nobody dares mention. The whole point about net-centric warfare is supposed to be finding the enemy center of mass and eliminating it. Well, that sensor net is LCS's center of mass, take it out and the ships are virtually defenseless (and to make it worse, we've been there before)

[MKSheppard]

Misconceived how? I am particularly interested in the Skjold-class, for obvious reasons.

This takes us back a bit. During the 1970s and 1980s there was a great drive towards the use of fast attack craft as primary surface combatants. Basically the argument was that these ships packed the wallop of a frigate yet cost far less. The idea found particularly fertile ground up in the frozen north and Baltic for a variety of reasons but the idea of the FAC-M gained a cadre of dedicated supporters who clung to their beloved craft with all the tenacity of Betamax supporters and Mac users (and people who like Glocks come to think of it). They could be identified by their continued chanting of "this is the way of the future and anybody who says otherwise is a hide-bound reactionary". On the other hand, there were fabulously clear-sighted, deeply expert and incredibly skilled analysts (modesty forbids me going further) who had deep suspicions about the whole idea. Basically their doubts stemmed from the fact that the FAC-M was a one-trick pony. It had its battery of anti-ship missiles and that was that. It had no air defenses, it was completely vulnerable to any form of attack and it was totally dependent upon shore-based command and control stations for target location and attack vectoring.

As the 1990s broke and combat experience with the FAC-M started to grow, it quickly became apparent that the problems with the FAC-M had been greatly understated even by their most erudite opponents. Put bluntly, the damned things were floating death traps. When FAC-M fought FAC-M from comparable navies, it was a one-for-one exchange rate. Basically, the two sides wiped each other out. Iran-Iraq war was a good example. Pitch a FAC-M up against a frigate and the FAC-M died fast and bloody usually without seeing the ship that killed it. It also quickly became apparent that the FAC-M was completely unsurvivable unless it was provided with heavy air cover which gave rise to the obvious point that one might as well hang the missiles on the aircraft and leave the FAC at home. Operation Desert Storm really killed the FAC-M. The craft were slaughtered without ever getting a chance to defend themselves let alone attack anything. For them, surviving was a very real achievement. By the end of ODS, the FAC-M was a failed concept, utterly discredited.

This really did not amuse the legion of ferverant FAC-M supporters. For a while, they could be identified by them turning up in various places, repeating stories of how "their" FAC/FAC-M had hurtled out from cover and peppered some unfortunate destroyer (almost invariably American) with gunfire. Checking into these stories proved that they were, without exception male bovine excrement. Mostly they never happened (in one case up north, the destroyer claimed to be the victim of one such attack was in the Pacific Fleet at the time) and were simply the overwrought imaginations of the FAC-M clique. Others omitted vital information (for example the exercise in question had been over for a couple of days when the "attack" took place or that the FAC in question had been spotted and "sunk" by a shipboard helicopter and therefore was making its attack from beyond the grave). These days, when somebody comes around with such stories WE BEAT THEM WITH CANES.

Once the period of denial and bullshitting was over, the FAC-M clique tried to regroup and come up with ideas that actually worked. About that time, Stealth technology was the in thing and the obvious solution was to apply stealth technology to the FAC-M. At this point it's necessary to digress a little. The real horrible weakness of the FAC-M was twofold. It was all attack, no defense and its on-board sensors were so poor that it was invariably seen long before it could see. Therefore, faced with a real warship, it would be killed before it couuld launch an attack of its own. However, the FAC clique believed that ***stealth technology*** would eliminate this fundamental weakness. It would achieve two things. It would cut down the search radius of sensors mounted on opposing warships and it would prevent radar-guided weapons on said warships locking in on the FAC. Out of this concept came Visby and Skjold. Reinforcing them was the idea that a significant increase in speed would allow the invisible FAC-Ms to get in and out to launch their attacks.

Thus invigorated, the FAC clique once again resumed their "this is the way of the future and anybody who says otherwise is a hide-bound reactionary" offensive. Again, note, no evidence to back up their assetions other than highly dubious third party stories that fell apart on close examination and impassioned rhetoric. The Swedes came up with the idea for the Visby class; the proposal here was to build a class of 15 - 20 multi-role vessels that would replace the existing fast attack, mine warfare etc fleet. The Norwegians produced the Skjold design (the logic behind that being that Norway had a huge coastline so a high transit speed was necessary to get between critical areas while stealth would prevent them being seen. However, there were already serious doubts about the whole concept so the navies built prototypes. The Swedes built the Smyge, thw Norwegians the Skjold. Essentially, these were proof-of-concept ships stripped of anything that cost real money.

Both failed completely. It turns out that Stealth at sea is a short-lived phenomena; it depends on exact ship proportions and ships move and change with the sea. The wake proved to be unhideable and it glows in the dark most of the time. Real warships already had electro-optical gear that was fully capable of getting visual spots. The new prototypes were just as vulnerable as the older designs. Thens omething really startling was discovered; the "stealthy" FAC-Ms had massive radar cross-sections. They weren't less observable, they were more so. The reason why proved to be quite logical; by designing them to minimize observability, the designers had been forced to solutions that generated large spray clouds. Those spray clouds were major radar reflectors in their own right and gave the effect of a ship moving around in its own private chaff cloud. Smyge was pretty bad in this respect, Skjold was and is horrendous. As long as they drift without power, both ships are indeed quite hard to spot on radar. As soon as they start to move, on Skjold even at slow speeds, they become glaringly obvious.

Both navies looked at the experience gained and shuddered. The Swedes mothballed the Smyge (I believe she is a museum ship now where naval cadets are taken and told if they propose something similar, THEY WILL BE BEATEN WITH CANES). The Visby program was slashed from 15 - 20 hulls to five. Even so, they're abortions with massive electronic problems. Great candidates for the deep sea target game. The Norwegian Navy got the Skjold back from the USN after we'd leased her for a whle (our verdict being "this ship has no conceivable use or value" - in the special forces support role the Cyclone class were considered to be much more effective). The Norwegian Navy then tried to cancel the whole program. They made repeated efforts to do this between 2001 and 2007 with, for example, General Sverre Diesen describing them as being "of negligible military value". The Norwegian Parliament kept refusing pleas to allow the cancellations and kept restoring them to the budget (allegedly because the shipyard was paying off key members of the government. The truth of the matter is that the tactical rationale for the Skjold class has long since vanished. The Norwegian coast isn't threatened by anybody and Norwegian strategy looks to stabilization and intervention operations far from home. The Skjold herself was an interesting experiment, but the passage of time and changing operational requirements have left the concept behind. On purely military grounds, the entire program would have been cancelled almost a decade ago. The continued construction of the Skjold class was purely a matter of a political decision to support a shipyard that has no other military business. This wasn't even an investment in preserving necessary defense infrastructure since the yard is of no great value to the naval shipbuilding industry. The Skjold program is corporate welfare at its most blatant, spending scarce defense funds on a program that offers no corresponding military capabilities.

The Skjold class makes an interesting comparison with the Chinese Project 022 missile-armed fast attack craft. The two represent different approaches to a similar tactical requirement; Skjold is a surface effect ship that rides an air cushion generated by lift fans. The Project 022 is a much simpler design using a wave-piercing catamaran hull. Both ships carry similar armaments allowing for national origin. The big differences lay in two areas. The conceptually simpler Chinese ship sacrifices much in the way of speed, apparently being capable of around 36 knots as opposed to the Skjold's 45 knots. However, so far, more than 40 Chinese craft have been built (out of a planned total of 100) and are in operational service. Ten years after the conceptual prototype was completed, the Norwegians still have to complete their first operational Skjold. Given that both the Chinese and Norwegians envisaged their fast attack craft adopting a loiter-ambush attack strategy, it is hard to deny that the Chinese have achieved the better design solution. Both countries have a long, rugged coastline to defend. The Norwegians adopted a philosophy of using high transit speeds so that a small number of craft could move to the point of threat. The Chinese built their craft cheaply and in large numbers so that there would already be ships deployed at the point of threat. It's hard to argue against the proposition that the Chinese got it right.

[MKSheppard]

This still remains the best essay I have read on the project, and I'd like to request permission to either repost it here or if Stuart can do the honors himself.

It really should be mandatory reading for anyone even thinking of becoming a naval architect.

I've shown Stuart's essay on DDG-1000 to friends who are naval reservists, both officers and senior enlisted.

Once the reality of the issues with DDG-1000 sinks in, a typical comment goes like this, "The Navy has any number of processes and procedures to get the job right in designing and building a warship. How could such a thing happen?"

My response has been, "Remember what the Car Guys, Al and Ray, on NPR's Car Talk once said: You can be ISO 9000 certified and still build a Yugo."

Scott Brim wrote:
In August 2008 when it appeared DDG-1000 was on a pathway towards cancellation, the naval analyst Stuart Slade wrote up this informal critique of the DDG-1000 program for his audience on the stardestroyer.net website.

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STUART SLADE ON THE DDG-1000, AUGUST 2008:

At its simplest, nobody has any faith the ships will work; and if they do work, nobody quite knows what they will be working for.

DDG-1000 has been a screwed program right from the start. The people behind it broke every single rule of naval design and consciously did not discuss the ship or her basic theoretical precepts with anybody.

The ship was, you see, a break from the hidebound traditions of the past that tied the navy to obsolete ideas and prevented them from striding forward into the bright days of the future.

Those thirty words have doomed more naval programs than guns, torpedoes and missiles combined. Some of the hide-bound conservative ideas they discarded included floating, moving, shooting, steering etc.

The big problem was that they changed everything in one go. They wanted new weapons, new electronics, new machinery, new crew levels, new hull design. Everything was new, everything was a major break with past practice. Of course, it all ended in tears, there's no way it could have done anything else.

Examples. The ship is supposed to use a radical hull form to reduce its radar cross section. Great, only that hull form uses a wave-piercing bow and a tumblehome shape. Now, let’s look at this more closely. It’s a wave-piercing bow. That means it - uhhhh - pierces waves. In fact the water from the pierced wave floods over the deck, along the main deck, washes over the forward weaponry, hits the bridge and flows down the ship's side. Now, that water weighs quite a bit, several tens of tons in fact, and it is moving at the speed of the wave plus the speed of the ship.

That wave, when it hits the gun mount and bridge front is literally like driving into a brick wall at 60mph. The gun mount shield is made of fiberglass to reduce radar cross section. The wave also generates suction as it passes over the VLS system, sucks the doors open and floods the silos. The missiles don't like that. Spray is one thing (bad enough) but being immersed in several tons of water flowing down is quite another.

Then we have the problem of the water flowing over the deck. It is strong enough to sweep men off their feet. In fact, it’s so dangerous that ships that operate under such conditions have to use submarine rules - nobody on deck. But to work the ship, we need people on deck. Uhhh, problem here?

Now for tumblehome hull form. This means the ship's sides slope inwards from the waterline, not outwards like normal ships do. Now, we take a slice through the ship at the waterline. That's called the ship's waterplane. There's a thing called tons per inch immersion, the weight of water needed to sink the ship one inch. TPI is proportional to waterplane area. As the ship's waterplane area increases it requires more tons to make it sink an inch. As the waterplane decreases it requires fewer tons to make it sink per inch. Now, with a conventional flared hull, as the ship sinks in the water, its waterplane area increases, so it requires a steadily increasing rate of flooding to make the ship sink at a steady rate. If the rate of flooding does not increase, eventually the ship stops sinking. This cheers up the crew immensely.

However, with tumblehome, the waterplane area decreases as the ship sinks into the water. So, the ship will have a steadily-increasing rate of immersion at a steady rate of flooding. In short, for a steady rate of flooding, the ship sinks faster and faster. The ship will not stop sinking. This is immensely depressing.

The problem is the damage goes much further than that. As a ship with a conventional flared hull rolls, the increasing waterplane area gives her added buoyancy on the side that is submerging and gives her a moment that pushes upwards, back against the roll. That stabilizes her and she returns to an even keel. With a tumblehome hull, as the ship rolls, the decreasing waterplane area reduces buoyancy on the side that's going down, giving a moment that pushes downwards in the same direction as a roll. This destabilizes her so she rolls faster and faster until she goes over.

Having dealt with the hull design, we now move to the machinery. The DDG-1000 is supposed to have minimally-manned machinery spaces. This will save manpower etc. etc. etc. There's a problem, all of that automation doesn't work. It’s troublesome, unreliable, extremely expensive and it needs somebody to watch it and make sure it does it's job. In fact, its useless. It gets worse. The purpose of a crew on a warship is not to make it go around and do things. Its to try and patch the holes and put out the fires when other warships do things to it. Repairing damage cannot be automated (did I tell you that DDG-1000 was supposed to have automated damage control systems? Ah, forgot that but it doesn't matter, they didn't work either.) So, having designed a hull that sinks if somebody looks at it crosswise, we now remove the people who were supposed to try and stop it sinking.

Now we come to the electronics. Great idea here. Put all the antennas into a single structure and we can cut RCS. That causes a problem called electronic interference. The systems all shut each other down. And they did. Very efficiently. The radar suite on DDG-1000 was the world's first self-jamming missile system. Oh, they took down the comms and gunnery fire control as well.

Did I also mention that the flow noise from the wave-piercing bow was enough to prevent the sonar working? That was an easy problem to solve. Remove the sonar. Anyway easy way to solve the interference problems, use multi-functional antennas. That sounds good. One day, when they get them working, I'll let you know. MFAs are pretty good when used in their place, but NOT for operating mutually incompatible systems.

The gun. Ah yes, the gun. It fires shells, 155mm ones. Guided shells whose electronics can withstand 40,000G. The acceleration in the gun barrel is 100,000G. Oops. Problems.

Then we come to the missiles. They're in new silos, all along the deck edge. Can anybody see the problems with that? Like moment and rolling inertia? The designers couldn't, which proves they know slightly less about the maritime environment than the deer currently eating the bushes outside my office window.

Now, all these problems are occurring at once and the fact that everything in the ship is new means that one can't be fixed until the rest are.

And that is why DDG-1000 got cancelled.

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NOTE: Later in the summer of 2008, the Navy reversed course a second time and decided to construct three DDG-1000s, assuring that the program would survive even if truncated at just three hulls.

Fingolfin_Noldor wrote:
Sounds like the ship, from Stuart's description, will be among the most expensive white elephants ever built, if not the most expensive.

You know where the expression "white elephant" comes from? Most white elephants come from Thailand where they are considered to be both royal and sacred. So, in the good old days, when Thailand was still Siam and the French were still in France (in-joke for any Thai readers) the King would look over his aristocracy and decide if any of them were getting to be rich enough and powerful enough to be a threat to him. If they were, he would give them a white elephant. Now, since it was a royal gift, the recipient wouldn't be able to kill it, that would be an act of treason and give the king an excuse to execute him. Since it was sacred, the recipient would be unable to send the elephant out to work, that would be sacrilege and give the king an excuse to execute him. Since it was an elephant, it would eat him into bankruptcy.

So, you see, white elephants served a strategic purpose; DDG-1000 doesn't.

Patrick Degan wrote:
Almost as if they took the principles of writing a script for Star Trek and applied them to military design.

Stuart wrote:
That's pretty close to the truth. There's a small number of ideas that come up for the "new super-technology of the future" that will create a uber-ship if only the hidebound traditionalists in the design bureaus would etc etc etc" They crop up at regular intervals with only the time cycle differing. The short fat ship crops up regularly at roughly 18 year intervals (I was at a Parliamentary sub-committee once takinge vidence on the 1988 incarnation of the idea when one of the other witnesses read a report on the alleged advantages of the short fat ship. After it had been applauded by Giles, he revealed it had been written by Barnaby in 1886), the multi-hull comes up at roughly 23 year intervals etc. Now, what has happened over the last few years is that all those cycles coincided and everybody came up with all these ideas at once.

This is where Star Trek design art comes in. Science fiction films tend to give people the idea that if something looks futuristic enough and weird enough, it must be an advance on what we have now. All that is needed is the technology to make it work. So, people took all these weird ideas (it's not a coincidence that the two weirdest and least practical of the LCS designs were ordered into production while the practical, proven design was the first to be dropped), kludged them up into a single hull and then looked for the technology to make it work. After all, it looked futuristic, it looked different it had to be good, right? And if it looks as if it should be good, there has to be a way to make it work, right?

Now, sometimes one can get away with that; one can start a design process on something that should be workable and try to solve the problems as one goes. It isn't a bad idea in many ways, the USN did that with the Lewis and Clark AKEs; they took a conventional AKE design and put a wholly-electric engineering system into it. That's all, but getting it to work was a swine. Delayed the ships by about two years. But, it was the only thing that was radical in those ships so everybody concentrated on the problem and solved it. Once the problem was solved, NASSCO poured the ships off the line and the program is now ahead of schedule and so far under budget that the Navy is able to order two additional ships using the money saved from the first group.

The trouble with DDG-1000 is that everything is new; its literally as different from DDG-51s as the Startrek Enterprise is from CVN-65. Now, the catch is that individually, we can solve the problems; the trouble is that all the solutions contradict each other. The designers tride to hide it with technobabble and they gota way with it for several years. Then, too many people started looking at the technobabble and saying "hey, hang on a moment, I read that in 'The Trouble With Tribbles'" and the whole scam was busted. It only needed a few people to make the remark and everybody else started looking and spotted the problems. The result of that has been the Navy's credibility in Congress has been flushed down the toilet. Congress just doesn't believe Navy testimony any more. They question everything and make their own plans. In a very real sense, Congress is actually running the Navy now (certainly the shipbuilding side of it) and shaping the navy the way it thinks teh navy should be shaped. That's the real story behind the death of DDG-1000. Congress simply lost patience with the Navy.

Starslayer wrote:
How the hell can you not understand that having lots of broadcasting equipment in one place will interfere with itself if you've taken basic EM?

Stuart wrote:
The logic is that one can timeshare the antennas. In the old days when radars, EW sets etc were hardware-controlled, that wasn't really an option, one had to switch one system off before using another (Sheffield sank because of that. Sort of). Today, with software-controlled systems, we can flash systems on and off so that we can have two systems running apparently simultaneously but in fact they're alternating transmissions on a microsecond basis. A lso, one can steer antenna beams so that they don't interfere. Now, all that is very easy to say. Its also very easy to put a calico dress on a pig and call it Florence but its still a pig. Multi-tasking antennas is a lot harder in reality than it sounds in practice (for example, the primary beams may be clear of interefence but the side-lobes and harmonics may not be. Those things shift with transmission modes and what may be clean in one application may not be in another. So, what sounded like a good idea, turned out to be very hard to implement. To give you some idea, the first MFAs were suppose dto be used on the USS Harry S Truman (CVN-75). They still weren't ready for CVN-77 and their use on CVN-78 is looking iffy.

Starslayer wrote:
Why in God's name would anyone consider tumblehome now that you have no real danger of being boarded during combat?

Stuart wrote:
Tumblehome was adopted because of the over-riding requirement was to reduce radar cross section. Now, in a conventional hull design with flared hull sides, the outward slope forms an acute angle with the surface of the sea. That provides a strong radar reflection. A tumblehome hull with its sides sloping inwards forms an obtuse angle with the surface of the sea and that gives a weak radar reflection. (All right, who can spot the horrible flaw in that argument; I'll think of a nice prize for the first person to get it.). That's why the DDG-1000 had a wave-piercing bow. A comventional flared bow requires an outward slope. We can't marry a tumblehome hull witha flared bow because the transition between teh two will be structurally weak and have a nightmarish radar cross section. So, once a tumblehome hull has been selected, we HAVE to use a wave piercing bow. And now we've come to the horrible secret. The DDG-1000 hull wasn't designed by naval architects, it was designed by electronics engineers. They designed the perfect hull for reduced radar cross section and then gave it to the naval deisgners and more or less said "make it work" the answer "it can't" not being acceptable.

Stuart wrote:
A tumblehome hull with its sides sloping inwards forms an obtuse angle with the surface of the sea and that gives a weak radar reflection. (All right, who can spot the horrible flaw in that argument; I'll think of a nice prize for the first person to get it.).

MKSheppard wrote:
Let me guess, is it because the ocean is not a perfectly stable environment, and as a ship pitches and rolls; it's cross section changes a lot as the interface between the sea surface and the ship hull changes on a constant basis?

Stuart wrote:
Exactly; as the ship rolls, the angle between teh ship's side and teh sea surface changes all the time anyway. Plus the waves change that angle as well. Again, you see, we're coming back to the original problem; the basic configuration of DDG-1000 wasn't designed by naval architects, it was designed by electronics engineers - and they'd done most of their work for the aircraft industry. So they designed ships the way they'd designed aircraft

[MKSheppard]

Nuclear Powered Hydrofoil Battleships

The following is an edited cleanup of the interesting bits of a five page thread that began on 8/10/2004 when I posted the following as "Cebrowski: Develop Small Aircraft Carriers!"

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Friend of mine who's in the navy lifted the following from the USN's Early Bird Paper, so no linky is given:

Inside The Navy
August 9, 2004
Pg. 1

Cebrowski: Develop Small Aircraft Carriers From High-Speed Ships

Arthur Cebrowski, the retired three-star admiral who leads the Pentagon’s transformation office, defied convention last week by suggesting the Navy, long wedded to its fleet of massive aircraft carriers, should convert high-speed vessels into “very, very small” aircraft carriers.

He briefly sketched out a concept for distributed, seabased, tactical aviation that would use large numbers of minicarriers, each carrying a handful of short-takeoff-and-vertical-landing Joint Strike Fighters armed with very small, precise weapons. It was one of several ideas he discussed Aug. 4 during remarks at a Navy research and development conference in Washington, DC.

After acknowledging he likes the carrier variant of the F-35 Joint Strike Fighter, Cebrowski touted the characteristics of the short-takeoff-and-vertical-landing variant, which can launch and land without a great deal of runway space. He praised the network structure and sensors that are common to the entire JSF program. He stressed that the Pentagon’s Small Diameter Bomb program will increase the capability of any aircraft.

“We may be in a position [where] we’re going to run out of targets before we run out of war,” he said. “And what that means then is you have the possibility of moving to very, very small aircraft carriers in multiplicity in order to deal with the diversity of the threat.”

Cebrowski’s presentation included a slide about seabased, tactical aviation. The briefing depicts a carrier-like variant of a high-speed catamaran. The picture shows a slightly scaled-up version of the Joint Venture (HSV-X1) built by Incat. The original Joint Venture is 1,700 tons and 315 feet long. A fully loaded Nimitz-class aircraft carrier, which displaces about 97,000 tons, is 1,040 feet long.

The minicarrier version of Joint Venture, about 367 feet long, is depicted carrying five tactical aircraft and other items, including a couple of helicopters and some amphibious assault craft. These vessels would be network-centric and could contribute to seabasing, according to Cebrowski’s briefing. Under the heading “assured access,” the briefing argues the minicarrier would “correct tactical instability” and complicate enemy intelligence, surveillance and reconnaissance. The minicarrier would be more survivable against certain threats and less susceptible and vulnerable, according to the briefing. The idea would also allow the Navy to reduce manpower and costs, the briefing argues.

Large carrier-like ships “do not have to be designed around tactical fighter wings anymore,” Cebrowski told the audience. “They can be designed as large open systems, multipurpose, to be used for anything, to include an aircraft carrier of today, or a large-deck amphib ship, or a command and control ship, or a maritime prepositioning ship.” He noted the Joint Requirements Oversight Council recently blessed seabasing as a joint concept.

After the remarks, Rear Adm. Jay Cohen, head of the Office of Naval Research, told the audience he is a “big fan” of Cebrowski. Cohen noted Cebrowski “has pulled the stops here for his small carrier based on [an] HSV. What a platform. It’s probably about 2,500 tons.”

He said Cebrowski “has taken disparate technologies” including lightweight, high-speed advanced hull forms, which can be stabilized in high seas. Cebrowski “has taken” the short-takeoff-and-vertical-landing JSF, Cohen said, noting a vertical takeoff would not be necessary because of a ski-jump like feature included in the minicarrier’s design. This would avoid “a refueling scenario immediately after launch and afterburner,” Cohen said.

“And when you’ve got a ship that can run around at 50, 60 or 70 knots, and anywhere on the ocean you’ve got 10 or 20 knots of wind,” Cohen continued, “when you’ve got relative wind over the deck, how much of a catapult do you need to launch? How much of an arresting gear do you need to stop the aircraft? And what does this do to distributed, tactical airpower?”

In June 2001, amid speculation about a review of major defense programs that was under way at the time, Chief of Naval Operations Adm. Vern Clark told an audience of naval aviators in San Diego that big-deck carriers would remain in the fleet (Inside the Navy, June 4, 2001, p1).

“Let me assure you carriers are not going away. That’s not going to happen, not anytime soon anyway,” said Clark. “Hello! The product is in huge demand.”

Cebrowski is known for proposing radical change. When he was president of the Naval War College a few years ago, Cebrowski advocated creating a small fast ship he dubbed “Street Fighter.” The concept had fierce enemies at the time but ultimately inspired the Navy’s Littoral Combat Ship program.

Cebrowski “knows he doesn’t make a lot of friends,” Cohen told the audience. “He gets invited to a lot of places to try to affect change.”

-- Christopher J. Castelli

Right now, my comment is........simply

*narrows eyes and wonders about Cebrowski's sanity*

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What followed was a sort of talk about various things such as Cyclone class PCs, and could they accomodate a Phalanx, etc. The usual back and forth banter that follows, then we got into the REALLY memorable stuff.

Mike Kozlowski Wrote:
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Y'know, I was in the Air Force, f'r cripes sake, and I know this is a bad idea. Wondering if ADM Cebrowski was one of the guys pushing the Essex reactivation back in the 80s.
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In some ways Cebrowski is a sad case, he came up with one really good idea early in his Flag career and got marked as "the man with bright ideas". The trouble is that the expectation is that he would keep producing bright ideas and he's been trying to live up to the hype. This Mini-mini carrier isn't a new idea of his at all, it first came up in 2000, as a thing called Corsair. This was held out as the absolute proof that if you give a crazy idea a sexy name, it suddenly becomes practical. In the Business we call ideas like this "The Nuclear-Powered Hydrofoil Battleship."

Way it works is this. Somebody says "Gee, what will happen if we have in the fleet a battleship with 12 18 inch guns, 300 cruise missiles, an AEGIS air defense system and armor three feet thick all on a hydrofoil hull that weighs no more than 100 tons, is nuclear-powered, can do sixty knots and is ****stealthy**** so nobody can see it." They then do some wargames with the Nuclear Powered Hydrofoil Battleship and prove it will sweep the sea of everything before it.

So they then write learned papers that state emphatically

THE US NAVY MUST HAVE NUCLEAR POWERED HYDROFOIL BATTLESHIPS NOW!!!!!!!!!!!!!!

ANYBODY WHO ARGUES IS A STUPID HIDEBOUND REACTIONARY!!!!!!!!!!!!!!!!!!!!!!!!!!!!

When somebody points out the Nuclear-powered Hydrofoil Battleship can't be built, they say

WE WILL SOLVE ALL THE PROBLEMS WITH TECHNOLOGY!!!!!!!!!!!!!!!!!!!!

In the case of Corsair, bowing the design out of the water was very easy. We took a foot-print of the ship, took the foot-print of the planned aircraft and showed that its impossible to fit the aircraft on the hull. Not operate the aircraft from the hull, you can't fit the aircraft on the hull.

The Cebrowskites reply? Suggested the aircraft be stacked on top of eachother. I'm not joking, that's true.

In designing carriers, given today's aircraft, we have a rule of thumb that works really well. You can operate one aircraft for every 1,000 tons of displacement. It even works for frigates except you have to subtract the tonnage allocated to other roles (and you can work backwards as well).

If we want to change that relationship, we have to either dramatically change the technology of the aircraft or dramatically change the technology of the ship. Tinkering with either (and in this context, VSTOL is tinkering) won't do it - we have to have something dramatic. And that dramatic change just isn't even on the horizon yet.

A couple of PS comments. Can't put Phalanx onto a PC hull. Isn't strong enough. The Cyclone class is actually a Vosper-Thornycroft modification of a Project 205 OSA class originally designed for the Egyptians. Its pretty weak. Phalanx will rip it up something horrible. In addition, Cyclone was designed with a specific load in mind and the trim problems are truly aweful. A lot of Good Things originally intended for those whips had to be dropped as a result.

By the way, for their job, you don't want too much firepower. Could have hideous consequences.

What sort of hideous consequences?

Admiral's Command Bunker, Bahrein

"Well, Lieutenant Commander Theodore, explain yourself."

"Sir. Last night I was ordered to take my command, PC-6 Scirocco to patrol the anchorage against possible intruders. At approximately oh-dark-thirty we spotted a small craft, probably a Boston Whaler type vessel, attempting to approach the anchorage. We challenged the craft sir, it responded by adding power and accelerating in a direct line for the CVN-71. We observed one of the crew standing in the bow, waving what appeared to be a scimitar and heard him screaming "We are martyrs for Allah. Death to all infidels and the Great Satan America." Believing this behavior to be suspicious we opened fire.

PC-6, Sir, was recently refitted with a 76 mm gun forward coupled to a Mark 46 electro-optical fire control system. I am pleased to report that this system worked extremely well and, despite firing from an unstable platform at a small, fast-moving target, our second round scored a direct hit, destroying the target completely. There was a major secondary sir, that confirmed the craft was indeed a suicide bomb.

Sir, it was pure bad luck that the first shot we fired ricocheted off the sea surface and hit the CVN-71. We were fortunate though, instead of impacting the ship's side and damaging her primary structure, the shell entered through the elevator opening in the hangar deck and struck the underside of the gallery deck. Most of the fragments were absorbed by the protection installed there and the shell inflicted little substantive damage. In fact the only thing of importance damaged was the basketball hoop used by the crew for recreation.

Really, sir, nobody could have anticipated that the basketball hoop would fall on the F/A-18 parked underneath with enough force to rupture one of the fuel tanks. I believe the hangar deck crew acted with great skill and efficiency. their efforts really do deserve commendation Sir. They contained the fuel spill, managed to absorb most of the spill, and the small portion that was ignited was quickly extinguised. Also, sir, I believe that the designers of the fire isolation doors in the hangar deck should be praised for their highly successful design. On detecting the flare-up of fire in the deck, the doors closed well within the specified 15 seconds and isolated the area of the fuel spill.

It really is a pity about the fully-loaded F-14 that was in the way when the doors closed. Still sir, we should look on the bright side, the aircraft is being withdrawn from service anyway and would be replaced for our next cruise. It is also good to know that the doors did function as advertized and cut completely through any obstruction to their closing. Of course, it is unfortunate the fire and electrical shorts caused when the F-14 was cut in half caused one of its missiles to fire.

We were most forunate sir, and it says much for the designers of our weapons that this accidental discharge did not cause a major hangar-deck explosion. In fact, sir, the safety device in the fuze worked perfectly and the missile struck the base of the forward sponson without exploding. I do not believe sir that our standing orders concerning the Phalanx mount on that sponson should be revised; after all, had this been a hostile missile, the burst of 20 millimeter fire would have been an invaluable last-ditch defense.

As it was sir, the burst of fire only just missed the accidentally discharged missile, a most commendable performance if I may say so Sir since it was at the extreme edge of the mount's arc of fire. It was indeed something of a pity that the stray shots hit the fuel bowser on the keyside but CG-59 was preparing to go to sea and it was essential she load fuel for her helicopters. The crew reacted very quickly sir when the fuel bowser exploded and I think we should very proud of the Navy's training standards in that they almost managed to disconnect the fuelling hoses before the fire flashed along them into the ship's bunkers.

At that point, Sir, I regret to report the situation took a turn for the worse. The crew proved unable to contain the resulting fire on CG-59. As you know sir, she is a special weapons platform with nuclear-tipped Tomahawks in both fore and aft magazines. However, there is good news sir. We've always been told that nuclear weapons will not cook off when subjected to intense heat and it is very fortunate we found this is incorrect here rather than in a port back home. Also sir, we were very lucky in that not all the nuclear warhead on board exploded. In fact Sir, I believed that a proportion of them fizzled and only contributed a few megatons to the cumulative initiation.

Also, Sir, I believe we must be appreciative of the fact that the resulting blast and thermal flash waves set fire to only three of Saudi Arabia's oilfields and not quite all the storage facilities and petrochemical factories exploded. I am reliably informed sir that the immense cloud of black smoke blotting out the sun this morning has prevented any of the news cameramen in the area from filming the event and this gives us a degree of plausible deniability.

Sir, we must also recognize that this incident has enabled us to provide a final answer on the much debated questions of global warming and nuclear winter. Scientists have been much exercised by that debate sir and we can now give them some solid and conclusive evidence to work from. Indeed Sir, we ought to make arrangements to give papers to scientific conferences on the matter. We could possibly use this as a valuable recruiting tool.

Anyway, Sir, that is my explanation for why it is currently snowing in Riyadh."

Is there a point to that lengthy and most amusing tale SEER?

Are you suggesting that unknown small vessels be allowed to cruise right up on a US warship uncontested?

Let's change your scenario to start like this:

"Sir, the incoming vampire we engaged with the 76mm got close, but we hit it. A great shot, one in a million. Good thing too, we think it was an SS-N-19 headed across our bow for the Enterprise. Unfortunately, some of the 76mm rounds that missed the missile didn't miss the enterprise..."

If an inbound vampire is engaged with point fleet defenses there will be rounds flying all the hell over the place. Doesn't mean we shouldn't still engage the missiles though, does it?

Is there a point to that lengthy and most amusing tale SEER?

Yes, The was asking what the horrible consequences of using inappropriate weapons in a crowded anchorage could be. (By the way Kevin, I know about lock-out zones but the Cyclones don't have a centarlized command system. In fact they are very austere inside - I've spent quite a bit of time in one.) The story was deliberately hyperbole because it wa sa boringa fternoon.

The Cyclones are nowhere near covette sized; in reality they are a 38 meter fast attack craft that has been stretched to 52 meters by lengthening the gap between the frames. Corvettes are a minimum of 70 meter hull length (the 62s are right on the borderline between the FAC and corvette category)

They are very, very cramped inside. Most of the hull is taken up by the four diesels and the control station between them. Aft of the diesels is the quarters for the SEALS. The galley and mess deck is literally about the size of a restaurant booth. It has a microwave and a coffee pot. About the only spare space is the CIC under the superstructure. In the original Russian design, this used to be the missile control room. Now its primarily an EW center.

The reason behind the Cyclones and their armament is that they were designed as SEAL insertion craft. They don't need - in fact would have no use for - a heavy armament. Giving them one would be counter-productive. Also, they had to be cheap enough to order in the required quantity. The US Navy paid US$25 million per Cyclone. A Phalanx costs US$7.8 million, a 25 mm Bushmaster US$38,000. A Bushmaster/Mk.19 stabilized mount costs US$450,000.

They carry a lot of topweight, mostly splinter protection on the bridge and hull. By the way, don't take the fact the Israelies do something as proving it can be done. Their ship design is abysmal bordering on ludicrous; their definition of designinga ship is "add another weapons system and see if it stays upright". For example, the Lahavs were designed to carry 8 harpoon and 8 gabriel anti-ship missiles, 32 Barak anti-aircraft missiles, an OTO Melara 76, to Sea Vulcan 20 mm guns and a Phalanx. In reality, they carry four Harpoons, a Phalanx and two 20 mm guns - the rest is prohibited by inadequate stability.

However, the simplest reason why the Cyclones are armed the way they are is that was the spec. The weaponry is intended to support the SEALS in a short-range blasting match. Bushmasters, machineguns and grenade launchers do that better than a Phalanx. By the way, the Phalanx would be a dead liability because of its fire control. the Cyclones are deisgned to work passive, ie without giving radar, radio or light emissions. A Phalanx would be a great big Neon sign pointing right at them.

Having said all that, the Cyclones were failures. Not because of their armament but because they drew too much water to get close enough inshore. That being the case, the US Navy really has been scrabbling around trying to find a use for them. They were optimized for a specific job and they're not worth spending money on to adapt to another role. The basic idea behind them was good and the SEALS now have another craft that does the job better

Are the Cyclones still doing maritime interdiction work with the USCG? How's that working out? As I noted above, they do look as though they'd be good at that sort of thing - enough firepower to shred anything small and discourage anything big, and with the necessary boats and personnel to conduct boarding operations.

They've been tried for it, the problem is that their hulls aer a bit light; the primary requirement for a Coastguard cutter is that they should be able to stay out in really bad weather. The Island class cutters (34 meter) are basically the same design but with the original frame spacing. They're a bit too small and are gettinga four-meter hull plug under Deepwater. (It was the Island class by the way that lead to the selection of the Cyclone design). The Islands work pretty well.

what was Cebrowski's one good idea?

He originally came up with the basic idea behind netcentric

So, I read alot of aviation stuff, but, frankly, I'm a novice, tangentially interested naval type. Let me try to understand this:

Cebrowski wants to operate 5 x 25 ton CTOW aircraft from a 3000 ton ship:

Hmmmm....what is the deck load imposed by a 25 ton aircraft, landing vertically over approximately 700~800 sq ft, with a 40 ton engine blasting down for all its worth? Can you possibly build a 3000 ton ship stong enough to support it? More unobtanium, please!

Assuming you can, what do you give up to maintain that strength that high above the waterline? And, how many other capabilities are you giving up to support this notional fleet of 3000 ton ships?

Stuart has stated that approx 10~15 percent of a ship's cost is hull; the rest is electronics and weapon systems. Now, we need to dramatically shrink existing weapons systems to fit into this radically smaller hull. How much will that cost? Can it even be done? And if so, what cost are you paying for that capability? Why are you paying 30% of the cost of a full blown CVN for your CVL (L=little)? So you can replace a 90 aircraft CVN with 3, 5 aircraft CVLs? Which can't operate the aircraft in severe sea states? With no maintenance beyond simple line maintenance? With insufficient deck park for even the F-35B? Without even the most basic of self defense weapons? All the while requiring fantastically advanced networks to link together potentially dozens of different platforms to coordinate a strike currently performed by 1-2 CVNs?!?!?

Whatever Cebrowski is smoking, I want some.

[MKSheppard]

These quotes came after news of corrosion appearing in LCS was posted.

It turned out that three factors had coincided to produce a perfect storm of galvanic corrosion. The first factor was that normally, such ships are equipped with a Cathodic Protection System (CPS). Originally, the LCS-2 design did include cathodic protection in the waterjets, alongside coatings and insulation, but it wasn’t enough, and some of the insulation wasn’t installed properly.

The second problem was that the corrosion protection system was also designed in keeping with commercial principles, which emphasize regular inspections and repair of corrosion. Military use does not allow the luxury of running clock-like regular schedules that allow such inspections to be scheduled into routine operations, so the problem went undetected until it had reached epidemic proportions.

The final problem was that there is a big difference between the electronic fits on merchant ships and warships. There are a lot more electronic systems on the latter and they run at power levels that are an order of magnitude (or more) greater than their civilian equivalents. This means that the stray electrical currents that are the basic cause of galvanic corrosion are much more common and a lot more damaging. This was actually the fundamental issue; the powerful radars and other electronic equipment were setting up eddy currents in the hull and they were greatly accelerating the whole galvanic corrosion issue.

This effect was unsuspected and its occurrence/non-detection was the result of moving a technology into entirely new waters. There was a very steep learning curve involved, but once it had been completed, it was realized that the problem was actually a known one with a known fix. It was just that the unsuspected interplay of powerful electronics and galvanic corrosion meant that a lot more of the fix was needed.

To put this into context, repairing the damage and fixing the issue so it wouldn't recur cost US$3.2 million. That's pretty much peanuts.

Nothing new under the sun. Several years ago I read, possibly in one of Norman Friedman's books. about an early French aluminum hulled torpedo boat that disintegrated in only a few years. The fact that it was moored near a sewage outlet apparently did not help.

That'll do it - although the chemistry was quite well understood, it was the implications of the chemistry that got overlooked. If you want some similar stories, trying to clear acoustic mines that were laid near sewage outfalls was - interesting.

What happened with Independence was a bit different. Nobody had ever put a powerful radar in an aluminuum-hulled ship before and the eddy current problem came completely out of left field. Essentially, turning the radar on actually drove the galvanic corrosion. Nobody was expecting it and I understand theoretical physicists got quite excited over the discovery. (There's a plot there for an episode of The Big Bang Theory there. Dr. Sheldon Cooper goes on a warship to investigate the phenomenom and meets The Senior Chief . . . . .)

Bernard Woolley wrote:
Probably an ignorant question, but given the experience of the Belknap Fire and the Falklands War, why is anyone still building warships out of aluminum?

When speaking of Aluminum, what's really meant is aluminum alloy. The characteristics of aluminum alloys are immensely variable and they are a far cry from the alloys that were used back in the fifties or even the eighties. Aluminum gives some very useful properties including reduced weight and increased stiffness (aluminum alloys weigh about a third as much as steel therefore the plating can be thicker making the hull that much stiffer). There are some complex balances that are struck there by the way and the decision between the two isn't straightforward. It's much easier to extrude aluminum into unique or unusual shapes and that allows design options that would otherwise not be available. However, the fact these shapes are unusual means that extra care has to be taken over their stess levels. It's easy to get carried away, create really unusual shapes that then cause structural discontinuities and thus excess stress loadings.

Aluminum can be cut and welded much more easily than steel although it requires much greater cleanliess when welding. A lot of the "problems" with aluminum are actually due to sloppy working practices. Aluminum plating can be bent more easily than steel (much more easily than in the case of some recent steel alloys). Again, doing this to excess especially in tight radii can cause cracking.

The corrosion and other resistances of aluminum depend enormously on the alloy. Aluminum alloys are hard to paint and require carefully controlled environments to be successfully painted.

I'm sure I've also read that it is difficult stuff to repair when damaged

Again, it depends on the alloy used. The only aluminum alloys recommended for maritime use are the 5- and 6-series alloys. The 2- and 7-series alloys which were developed for aircraft use are completely unsuited for maritime use and are largely responsible for Aluminum alloy's poor reputation. 5-series alloys with more than 3 percent magnesium seem to offer perfectly acceptable service characteristics although there are still problems with exfoliation and intergranular corrosion. The real problem is that when an aluminum alloy plate goes, it really goes. The whole plate has to be replaced. There's also some evidence that exposure to the sun can accelerate some aluminum alloy corrosion, especially of the intergranular type. On the other hand, running in sewage (unfortunately common in some ports) can accelerate exfoliation corrosion. It's worth noting that some unpainted all-aluminum alloy vessels have operated for thirty years in maritime environments without ill-effects from corrosion.

The real problem with repairing aluminum structures is welding. Welding aluminum is pretty easy all things considered and a butt-weld will solve most problems. But, here's the thing. The aluminum being welded has to be scrupulously clean - like microscopically clean. Trying to weld an aluminum structure at sea in a salt-spray filled atmosphere is futile. I suppose the best summary would be that the repair is easy but getting the right conditions to do it can be really hard. Also, convincing people that all those cleaning and other precautions are really important is hard. It's pretty much essential to stand over the dockies and make sure they don't take short cuts. For example, wiping with a dirty rag soaked in dirtier water does not produce "microscopically clean".

Aluminum is favored as a structural material because it generally has less maintenance and repair over the life of the vessel, but the designer must be certain that the structure is sufficiently rugged to stand up to all service conditions that will be encountered, including abuse from cargo handling and slam loads. Access for inspection and repair should also be a design consideration. Provided these criteria are met, aluminum does not cause any great maintenance or repair problems.

Mark Bailey has also mentioned that the RAN Armidale class will have a shorter life than otherwise because they use aluminum in their hull.

Uhhhh . . . . . . . I am sure he does.

In the real world, the Royal Australian Navy specified a hull life for the Armidales that was independent of whether the ships were built of steel or aluminum (or composites or wood or whatever). The design selected meets that criteria.

If you want a detailed analysis of this issue, I'd refer you to SSC-452 ALUMINUM STRUCTURE DESIGN AND FABRICATION GUIDE published by the Ship Structure Committee of the U.S. Coast Guard. It's 365 pages of structural gold and is the bible for designing and building aluminum ships. By the way, note the way that is phrased. We can't build an aluminum ship usinga design intended for steel or vice versa.

Bernard Woolley wrote:
All that said I can't imagine that the RN would procure an aluminium superstructure, never mind one with an aluminium hull (though I could be wrong). The memory of what happened in 1982 is, AFAIK, still very much there.

Oddly, the worst fires were on all-steel ships. The primary culprits were flammable wiring, inadequate firefighting provisions and poor damage control training. I must admit, I don't like aluminum and would rather not see it used by it does have its virtues.

and was quite scathing of the decision to go with aluminium. IIRC his complaint was that the Armidales will be smashed about in the Southern Oceans and aluminium hulls won't last as long in those conditions.

That doesn't make any sense at all. One of the reasons why aluminum is useful is that it allows the hull plating to be substantially thicker for a given weight of metal. Extrusion can also be use dto make much more interesting shapes than steel and that tends to increase strength. Because of the light weight of aluminum, more metal can be put into hull members, for example increasing the radii on Tees, thus further decreasing stress. One of the curious things is that aluminum decks in particular tend to flex when one walks on them. This is perturbing and has been known to upset matelots of a nervous disposition. However, its actually a good thing because the structure is absorbing loads rather than transmitting them. It's worth noting that aluminum plating is actually less prone to buckling than an equivalent weight of steel due to its greater thickness.

In the end, though, we come back to the same point. The Armidales were designed for a specific life and that life was independent of what they were made of. So, they'll last the targetted life. Saying they won't last as long as a steel ship is quite meaningless.

drunknsubmrnr wrote:
Damage Control priorities are float/move/fight. The reality is that nobody makes it to fight, it's always a struggle just to get to float and move for small warships. LCS isn't compromised any more than other small warships that way. That being said, it may take less damage to get to a CTL once they're back in port.

There are a couple of trains of thought here. One is that with modern weaponry, the probable outcome of a hit isn't CTL but ETL (explosive total loss). Another, less cataclysmic one, is that so much of the value of a modern ship resides in its systems and these are so vulnerable to fire that even relatively minor damage can CTL a ship. A good case was Miami when she was vandalized in port. By the time the damage had been finally assessed, she was CTL. The repair bill would have been roughly equivalent to the cost of an LCS with the major component being re-wiring the ship and replacing the systems.

Don't repair, replace was one of the thoughts behind the WW2 DE design. It was assumed there that the most likely hit the ship would take was a torpedo and that the chance of a ship that size taking a torpedo hit and surviving was slight. Therefore, there was no point in including major investment in DC. In fact, things didn't work out that way.