The Ship Model Forum

I tried. I really tried to leave this alone, but I cannot.

I served onboard Gas Turbine and Nuclear vessels. USS Long Beach (CGN-9), USS Truxtun (CGN-36), USS California (CGN-36). Allow me to compare the most relevant of my cruises:

USS California and USS Kidd. One Nuke, on Turbine. Onboard Kidd, we would BSF (Brief Stop for fuel - we were not operating with any support vessels) every week. Onboard California, crew endurance and morale dictated port visits. Both of thses were six month crack-pacs (CD OPS/Counter-Drug OPerationS) in the same exact stomping ground. Both would take whatever opportunities were availible to top off fresh supplies, but do not mistake that for a 'need' to replenish. In six months, California did ONE major replenishment of the food stores. In six months, Kidd did four. Kidd carried approximately half the crew of California.

Truxtun was repeatedly tasked with speed runs and station changes precisely because she would not have to burn oil to do it.

In a 53 day stretch aboard Long Beach, we did not run out of milk for nearly 1000 Sailors (milk can be frozen, and the elimination of the space required for fuel allowed for a massive amount of provisions to be carried), even having it out for midrats.

HMS Manchester would RAS every three days from one of the Rover's which was deployed with us.

Nuclear Escorts DID NOT have to reprovision as frequently as oil powered ships. This is based on my Navy career serving on both.

Using a CVNs UNREP to support the need for a nuclear escort to replenish is disingenuous. A CVN is not an escort. Further, the CVN carries 6000 personnel. One of the Nimitz class' strength was the design decision to use the space saved by not having to store ownships fuel for munitions and JP-5. Primary driver for CVN UNREPS is JP-5, thanks to the gas hog known as the F-18 - in all of its forms.

Many examples have been cast showing nuclear vessels as more expensive. They are more expensive to build, and they are more expensive to man. The increased build cost is self-evident, but also includes 25 years of fuel (on modern cores. But even USS California got nearly 20 years of life with 16 of them active operations on a core designed in the '60's and installed in 1970 - her core installed in 1990 should have given her 20 more). The personnel are more expensive - they require more training and retention incentives, but even the most modern nuclear escort was saddled with a reactor design from the 1950s.

Surely we could do better today - after all, the gas turbines these plants are being compared to did not exist in 1950.

Gas turbine ships require more time off station to fuel. The require more supply ships to bring that fuel (adding the cost of another ship and crew), or lose more fuel and time traveling to a port to refuel. Those supply ships or ports need to be defended, adding the cost of manning and building the military asset which performs this task. The have increased exposure to risk due to more UNREP operations, a very dangerous evolution. Gas turbines leave the Navy's operational budget at the whim of market forces - oil prices rise, but the operational budget takes over a year to react.

How did a BSF go for USS Cole?

I was Honored to stand at the funeral of a USS Cole Sailor. Shame I had too.

That being said, to me, the only real cost comparison should be time on station (cost per hour on station), and all of the 'nukes are more expensive' arguments avoid this completely. Savings would be realized if properly employed.

But does that matter if your country doesn't have the money now to build nuclear-powered ships in appreciable numbers? Is it better to have 10 diesel/gas ships that you can afford to build and buy in the next five years and have them cost you more over the next 40 years or is it better to have 5 nukes over the next five years and cost you less over the next 40?

(numbers somewhat arbitrary)

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De quoi s'agit-il?

Actually, that is a perfect example of why hours on station would be a perfect comparison tool - if you can only buy two nuclear vessels for three turbine ships, that should be shown in time on station.

(comparisons which led to the DDG/CG-47 class stated one nuke for two GT ships, in very deceptive accounting, in my opinion. Two to three is probably pretty close for a vessel with similar equipment)

Further, other long-endurance options should increase in value, such as a combined diesel/gas turbine vessel. In that case, transit time may work against the diesel vessel, but maybe the endurance can make up some of it, and costs to each of those hours is always relevant, including acquisition and operation costs. Defense/patrol of a relatively fixed position is perfect for this kind of vessel.

That being said - coverage of a given area is enhanced by a higher sustainable speed (that is, the area which can be covered by a fast vessel is greater), as is the possibility of fast reaction, increasing the operational capability of the long endurance AND high speed vessel.

In a perfect world, you get a blend of all of the above.

Keep in mind I'm not talking about simply costing a hull on station - I would estimate costs for capability over time. In many cases, the operational need should define a lower cost, high endurance vessel. In others, a high capability vessel is needed. I project that once you find that a high capability vessel is needed, it is cheaper to have a higher endurance on that vessel (as you have already sunk costs into expensive systems)

Right now, we cannot use the mobility of our CVNs to full effect because they have no escorts which can keep up with them.

What about maintenance cycles? With fewer ships, the time out of service will hurt even more.

(Surely RAND must've put out a monograph on nukes versus non-nukes...)

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De quoi s'agit-il?

Fewer platforms will mean it hurts more if one is out, however the time that a nuke would need nuke specific work (refuel) is the same time the conventional vessel needs an overhaul/rebuild (20-25+ year mark). New vessels have a very long core life projection - the S9G is projected to have a core life of 33 years, probably the life of most vessels.

As far as numbers go, to use your 10 vessel number, I would build a fleet of :

Two nuclear (for independent operations, 'first responder' roles with the fast transit, and/or fast escort of a CVN)- this would be CSGN
Four fully capable 'Turbine' ships for high density/battle group operations - this would be a Burke equivalent
Four Patrol/low intensity vessels (at approx .75 the cost of the 'full' turbine ship) - say a Diesel/CODAG - this would be a modern Frigate

So I would not see a loss in numbers, but a blend of capabilities. Not necessarily at this ratio - I was just trying to illustrate using the 10 ships mentioned above, and an Idea that a CSGN might cost 1.5 Turbine vessels, and a Frigate .75 of that turbine vessel.

I love the LM-2500 - it is very reliable and easy to maintain. It is also thirsty, and the USN is DECREASING the endurance of LM-2500 vessels in general - Burks have only a 4500nm endurance, compared to Spru's 6000nm endurance, increasing the Burke's reliance on a supply chain. this is not to say Burke's are bad - just to illustrate the navy has an endurance problem, just like when they let go of the F-14/A-6 for the short legged Hornet. Reduced range increases vulnerability for all assets involved (have to operate closer to the threat, have a smaller area of predicted operation, 'rear' units, like supply ships, have to be closer to the threat...ect)

The fossil fuel vessel does OK in Battle group operations, where many vessels are using the same supply vessel, but that limits maneuverability and make the supply ship a high value target as well

So a blend is what I advocate - not all of one or another. the Nuclear option really shows itself for independent or sustained high speed operations:
If you are out on your own, a supply chain will be very vulnerable - and expensive (another two ships (one supply, one escort for that supply) to keep one in action)
In high speed reaction, either solo or with a CVN, the endurance allows fast transit without being exhausted upon arrival, and as complete a freedom of navigation as is possible in a given situation. Arrive fast, be ready to fight and stand until the follow-up train of oil burners and supply ships come along.
That ability to consistently conduct high speed transits without fuel concerns enhances the defensibility of the asset, by increasing the potential area the enemy has to search in a given time.

Really from today forward we are probably talking about how to generate the electricity which drives a new vessel - most all will have electric drive moving forward.

Loving this discussion!

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In God we trust all others we track

Quick - lets buy her and do it right!

http://www.govliquidation.com/auction/v ... vertTo=USD

Comparison between conventional steam and nuclear steam ships.
http://www.navweaps.com/index_tech/tech-019.htm

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Mr. Minyard's comparison is certainly no longer valid for evaluating naval propulsion systems, if it ever was, because steam boilers are no longer in use. In fact, when he last updated the piece in 1998, steam propulsion was on its way out in naval propulsion and was gone from commercial use to the extent that it was a major problem to find merchant mariners who knew how to run steam boilers when cargo ships were pulled from the Reserve Fleet for use in the First Gulf War in 1990.

Likewise, his description of the power train from steam generator to propeller is dated for both nuclear and conventional propulsion systems.

I said, "if it ever was", because the comparison ignores so many points with regard to conventional propulsion systems. For example, cost. It seems to me that the comparison ignores the costs of support vessals to allow the conventionally powered warship to operate, (not to mention the lack of oilers that can keep up with warships deploying "All Ahead - Full" in a time critical scenario.) Therefore, a valid comparison of propulsion systems would compare the cost of refueling the nuclear reactor after 20 or so years with the cost of the fuel, including the cost of delivery, used by a similar conventionally powered ship cruising the same distance over the same period. Unfortunately, what this leaves out is the cost of a conventionally powered ship being "off station" to refuel. If that were to be monetized, we would have a far more accurate cost comparison. The ultimate cost comparison would be when the military/diplomatic utility of having ships that can deploy at full speed for days can be monetized so that the value could be applied as a credit to the nuclear cost ledger and a debit on the conventional cost ledger.

I thought that report sounded a bit elementary myself. I really liked they part that mention that a conventional ship can deploy just as fast as a nuke "except for the few hours it has to slow down to refuel" nice way to brush over that.......anyway. Nukes, come get some

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In God we trust all others we track

I don't think it was elementary, I think it was biased.

There is no support for any supposition in that list of "what I like about old-school steam boilers", and I don't think it is terribly relevant to the points brought up here.

The comparison brought up was the Gas Turbine - and the GT has NUMEROUS advantages over conventional steam. Plant replacement, weight efficiency, hugely reduced manning requirements, and reaction time to name a few.

Cost. The list does not address cost of time on station, or the higher support requirements of oil burners. Fuel costs are not lower for an oil burner today "considering the costs of a refueling overhaul for a nuclear powered ship" because a modern CGN would not have to have a nuclear specific refueling overhaul in her lifetime. Manning levels should be higher and more expensive than a GT plant, but should be much lower than the older D2G/C1W plants. How much is a barrel of oil today? what does it cost to get that oil to the vessel?

Flexibility. This reference to design is a red herring. There is no intrinsic advantage in design of either, but both need a hull design to exploit their strengths. Conventional hulls need to be efficient for cruise, nuclear hulls can be efficient for top speed. Conventional hulls need to have a large liquid loads and nuclear needs to deal with heavy shielding in design. "Flexibility" should be addressed as what the vessels can do - not implying flexibility of design - only one basic hull design was ever used for both conventional and nuclear.

Efficiency. Non supported statements. "Carry over" shows the author does not understand the nuclear steam cycle.

Redundancy. This is completely nonsensical. Two Engine rooms. Two shafts. Both have the same redundancy.

Diplomacy. Correct that some 'allies' do not allow nuclear vessels. When we have a major battle near New Zealand, this could be the tipping factor.

Range. yes. well, and speed. and endurance. These are a huge tactical assets, and expensive. This is why we need a blend of GT and nuclear...

Survivability. Probably better on a nuclear vessel. Allot less JP-5.

Signature. Again, GT are very good a quieting, we have gotten very good at suppressing the IR sig of GT outgasses - just one more line that makes me believe this link is not relevant to our discussion.

Essentially what that link does is compare the Leahy/Belknap Class to the Truxtun, which does not really set us up for a modern nuclear power debate. And you will notice the manning requirements of a Belknap CG and Truxtun are very similar.

I went over to the general electric web site and got some info on the LM-2500

LM2500
Output: SHP 33,600 (25,060 kW)
Fuel consumption: 0.373 pounds/SHP-Hour
Thermal Efficiency: 37%

LM2500+ (LHD-8)
Output: SHP 40,500 (30,200 kW)
Fuel Comsumption: 0.354 pounds/SHP-hour
Thermal Efficiency: 39%

LM-2500+G4 (French and Italian FREMM ships)
Output: SHP 43,370 (35,320 kW)
Fuel Comsumption: 0.354 pounds/SHP-hour
Thermal Efficiency: 39.3%
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Rolls Royce MT-30
Output 48,000 SHP (36,000 kW)
Fuel comusmption: couldn't find a solid number
Thermal Efficiency: @40%

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The mighty LM-2500 has come a long way since its first 20,000shp version.

I saw those numbers for LHD-8 and was amazed - now you can have 80000shp with two LM-2500 instead of the Spruance/Kidd/Tico four.

And the FREMM plants are even more powerful...

In an electric drive ship, two turbines and two diesels are even more appealing than before.

You should add the LM6000 (and other regenerative gas turbines) to the list.

Just getting back to this after a long absence. I'm not able to use the PM function (been a lurker, not a poster). Tried sending you an email, but not sure if it actually worked. I'm still interested in following up on this issue. I'm trying to get good copies of those two images and I'm trying to figure out who painted them and when.

I found this image in a museum, and was only able to take a poor quality photo of it. It is obviously from the same sequence:

That is the Aegis-Virginia CGN. Kitbash a model of a Virginia class CGN to get that one. Donald Rumsfeld canceled the Strike Cruiser just before Carter took office. The Aegis Virginia was canceled by the Carter administration, and revived and re-canceled by the Reagan administration.

The original plan for the strike cruiser was to build 8 of them. There would be four all nuclear carrier battle groups. CVN (x1) CSGN (x2) and CGN (x2) THe CGN pool would be the 4 Virginia, 2 California, Truxtun, and Bainbridge. With Long Beach being the alternate for ships refueling.

During the final design phase the 8" guns would be dropped and replaced with a single 5" and 2 44 round Mk26 mod5 launcheres fit. I don't remember which launchers were to be fit the Aegis Virginia.
The Virginia class had the Mk26 mod0 aft with 44 rounds, and the Mk26 mod1 with 24 rounds forward.
The two SPG-51 were aft and a single SPG-60 forward. The picture has 4 SPG-62, two forward, and two aft. Had they been built it would have been one at a time. The forth unit being ordered in the late 1980s might have been built with the Mk41 VLS instead of the Mk26, and ABL launchers.

Lots of room for changes.

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I do agree that the weapons fit would have evolved as the ships commissioned.

I think anything approved under the Regan administration would have commissioned with VLS, when you consider the design work and long-lead items needed to build the vessels, that would put completion right near the 1985/86 dates of the VLS Ticos.

In any case, as Mk 41 was intended to fit in the space of the Mk 26, these ships would have been refit to Mk 41 if they did commission with Mk 26, no matter which version was built.

.......

Sorry as Nuke model builder (and an Aussie...... ) I found that really funny.....

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building:
1/72 RC USS LONG BEACH CGN9
1/72 RC USS CALIFORNIA CGN36
1/72 RC USS SAIPAN LHA2
1/72 RC USS JOHN PAUL JONES DDG53
1/72 RC USS SHARK SSN591
1/72 RC USS SEAWOLF SSN21
1/72 RC USS ALBANY CG10

Also the California's and Virginia's would have still been viable platforms into the 2000's with the NTU upgrade (and any further enhancements to it) in her last RIMPAC (98 I think....) USS California (with NTU) out shot the equivalent era Tico's and Burke's from what I have read. It wouldn't have been a stretch to assume that the CGN36 n 37 and the Virginia's could have performed a very useful role well into the 21st century. If they hadn't been discarded by the bean counters.....

Bruce

CGN9 is being cut up at PSNS as we discuss this. what a waste of a hull.....

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building:
1/72 RC USS LONG BEACH CGN9
1/72 RC USS CALIFORNIA CGN36
1/72 RC USS SAIPAN LHA2
1/72 RC USS JOHN PAUL JONES DDG53
1/72 RC USS SHARK SSN591
1/72 RC USS SEAWOLF SSN21
1/72 RC USS ALBANY CG10