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Nuclear powered Battleship?

Posted: Wed Mar 22, 2006 3:21 pm
by Karl Heidenreich
By the time the USS Enterprise became operational nobody thought about modifying the powerplant of the existing Iowa Class Battleships? A problem that had been discussed a lot about the actual operation of those surviving Battleships is the cost of maintaining them and their dependence on being refueled constantly.
But that flaw can be minimized to a great extent modifying the powerplant by extracting the boilers an installing in their place a state of the art nuclear reactor arragement. By installing those reactors you will give those vessels 50+ usefull years as the Enterprise.

Posted: Wed Mar 22, 2006 4:37 pm
by marcelo_malara
Is that really possible Karl? What is the weight of a nuclear reactor compared to the boilers?

Posted: Wed Mar 22, 2006 4:58 pm
by Karl Heidenreich
Maybe Foeth can help us with this one. But if a Kirov BC with 30,000 tons and 253 meters lenght can carry her nuclear reactor I believe, for starters, that an Iowa Class can acommodate a reactor. Logicall Falacy?
Now, a 1960 reactor probably wouldn´t do it but a mid 70ies one will. As far as I know the USS Enterprise has several reactors while the USS Nimitz has only one.
But Iowa is a huge warship. It´s obvious that a modernization process would have been quite expensive but the question is other: will a brand new ship be as safe a gun and missile platform as an BB? I doubt it. The new warships aren´t as strong as their mothers and grandmothers. And they will be much more expensive. Look at what happened to USS Cole. That kind of damage is very difficult to happened to a BB under the same circumstances.
And a BB is quite a more beautifull vessel, even an Iowa.

Posted: Wed Mar 22, 2006 5:00 pm
by ontheslipway
I don't know anything about nuclear reactors...

Posted: Wed Mar 22, 2006 5:07 pm
by Karl Heidenreich
Sorry:
Enterprise has 8 nuclear reactors.
Nimitz Class has 2 nuclear reactors.
The US Navy had a lot of nuclear powered cruisers from the 60s. They were not huge ships as a BB.

Posted: Wed Mar 22, 2006 6:13 pm
by marcelo_malara
I can´t find anywhere the reactor´s weight. What I am thinking is that a reactor is far heavier than the boilers. I don´t know if it can be acomodated in the same physical space and if the structure would resist the concentrated weights.

Posted: Wed Mar 22, 2006 6:30 pm
by Karl Heidenreich
I look everywere and didn´t find the weight of naval reactors. But I do find the following information that might be helpfull:

U.S. Naval Reactors

1. The PWR/S6G Reactor of the Los Angeles Class SSN has 35,000 shp each and the sub´s displacement is 6.930 tons.
2. The PWR/S8G Reactor of the Ohio Class SSBN has 60,000 shp each and the sub´s displacement is 18,750 tons.
3. The PWR/S6W Reactor of the Seawolf SSN sub has 57,000 shp each and the sub´s displacement is 9,140 tons.
4. The PWR/A2W Reactor for CVN-65 Enterprise Aircraft Carrier has 35,000 shp each and the flatop´s displacement is 97,000 tons.
5. The PWR/A4W Reactor for the CVN-68 Nimitz Class Aircraft Carrier has 140,000 shp each and the flatop´s displacement is 100,000 tons.

Nimitz has 2 of these reactors so her output is more or less 280,000 shp.
The Enterprise has 8 reactors so her output is, again, 280,000 shp! It seems that´s the power to move an Aircraft Carrier at some 30 knots.
If an Iowa with her displacement of 57,340 tons @ full load needs 212,000 shp to reach 32.5 knots then she, probably and hypothetically, will need the equivalent of 6 of Enterprise´s PWR/A2W reactors (probably too much weight for our BB) or 4 of the PWR/S8G reactors of the Ohio Class Sub (which doesn´t sound that bad :? ).
The other issue that we haven´t explored is about those 1960ies USN cruisers that were on service until the mid 90ies.

Posted: Wed Mar 22, 2006 9:45 pm
by marcelo_malara
Well, find a nuclear reactor weight seems more difficult than getting blue prints to build an atomic bomb. The only reference I found was a paper at http://www.atomicengines.com/Ship_paper.html about the Savannah, a nuclear powered cargo ship. There is a table comparing weights of different powerplants. It gives 54 kg/kw for a nuclear steam plant (doesn´t say if the turbine itself is included).
So:

212000hp*.0746=158152kw ->158152 kw*54kg/kw=8500 tons

http://www.warships1.com/US/USbb61-Iowa.htm gives the actual machinery weight for Iowa as 4443 tons. That compared unfavourable. On the other hand you would save 9000 tons of fuel with the nuclear powerplant. The difference is that the fuel is evenly distributed along the ship, and the nuclear reactors are concentrated on a limited space. So, I believe that you can´t just take the boilers out and put a reactor in their place, you need a major redistribution of the machinery spaces to distribute the load.

Posted: Wed Mar 22, 2006 10:28 pm
by José M. Rico
I just wanted to comment that although nuclear plants are bigger than conventional plants and may require more space, when you look at the overall design, weight is saved since there is no need for thousands of tons of consumable fuel to be burn in the boilers. The nuclear reactor heats the water and produces the steam by itself.

Posted: Wed Mar 22, 2006 10:39 pm
by José M. Rico
marcelo_malara wrote:http://www.warships1.com/US/USbb61-Iowa.htm gives the actual machinery weight for Iowa as 4443 tons. That compared unfavourable. On the other hand you would save 9000 tons of fuel with the nuclear powerplant. The difference is that the fuel is evenly distributed along the ship, and the nuclear reactors are concentrated on a limited space. So, I believe that you can´t just take the boilers out and put a reactor in their place, you need a major redistribution of the machinery spaces to distribute the load.
Ups, you already mentioned that Marcelo. My fault for replying without reading the entire thread first.

Posted: Wed Mar 22, 2006 10:59 pm
by Karl Heidenreich
Still, an Iowa Class vessel with all her armour is, probably, the best carrier for a reactor. I don´t believe any actual vessel has an armour match for Iowa´s.

Posted: Wed Mar 22, 2006 11:23 pm
by Bgile
One advantage of being an anachronism is that there aren't any weapons designed to defeat protection like that, except of course for torpedoes and they would still be effective.

One of the major advantages of nuclear power is it doesn't require any air intakes or exhaust uptakes, so no stacks and no potential of filling the ship with smoke and reduced power if there are hits near or on these vulnerable areas.

One other point is that a reactor doesn't produce horsepower for propulsion directly. The ship is moved by steam turbines, and that is where the 280kshp or whatever is generated. For example, on a Nimitz class carrier one large load on the reactors is steam for the catapaults, and another is the steam turbine generators for the ships electrical loads. The reactors provide steam for the 280kshp (total) turbines in ADDITION to these other fairly major uses.

Posted: Thu Mar 23, 2006 12:01 am
by Karl Heidenreich
How much damage can a russian shipwreck missile or a Harpoon or a Maverick can do to a BB? Can the BB withstand it?
What about the Phalanx? Such a device can really destroy an incoming missile?
Because if the answer is that the nuclear powered BB stands against those odds, even with the help of the Phalanx, then we have a great surface vessel with great autonomy.

Posted: Thu Mar 23, 2006 12:36 am
by Bgile
Karl Heidenreich wrote:How much damage can a russian shipwreck missile or a Harpoon or a Maverick can do to a BB? Can the BB withstand it?
What about the Phalanx? Such a device can really destroy an incoming missile?
Because if the answer is that the nuclear powered BB stands against those odds, even with the help of the Phalanx, then we have a great surface vessel with great autonomy.
The latest block versions of Phalanx are supposed to be very effective, but they are last ditch weapons and you could saturate the system pretty easily. I think those weapons could do quite a lot of damage and you would need escorts - a BB wouldn't be able to operate independently.

I think shipwreck in particular would cause serious damage to anything it hit. Harpoon not as bad but all you have to do is look at the damage to S. Dakota as 2nd Guadalcanal to see how much damage you can do with no penetration of armor. Any ship is vulnerable to modern weapons, although a battleship could absorb quite a bit without sinking.

Remember when the British sank General Belgrano in the Falklands war? An old ship, but they didn't want her loose in their invasion area with 15 6" guns. It's all relative.

NUCLEAR BATTLESHIP

Posted: Thu Mar 23, 2006 12:49 am
by peter
How many BBs were sunk in WW2. Today a BB is a sitting duck. It might be able to withstand a terrorist attack, but that would probaly be its only advantage over modern naval ships.