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DeliciousFart

Electrical power output of battleships

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I think one thing that is often overlooked in ship design is the electrical power output. I've listed the total electrical power output of several WW2 battleships below. Note that for the total power output, I am not including the emergency generators, as those would normally not be on.

  Electrical power output Generators
King George V 2,800 kW 6 x 350 kW turbogenerators
2 x 350 kW diesel generators
Vanguard 3,720 kW

4 x 480 kW turbogenerators
4 x 450 kW diesel generators

Yamato 4,800 kW 4 x 600 kW turbogenerators
4 x 600 kW diesel generators
Bismarck 7,910 kW

5 x 690 kW turbogenerators
1 x 460 kW turbogenerator
8 x 500 kW diesel generators
1 x 550 kVA diesel generator

Littorio 6,800 kW 8 x 450 kW turbogenerators
4 x 800 kW diesel generators
3 x 62.5 kW diesel alternator groups
Dunkerque 4,800 kW 4 x 900 kW turbogenerators
3 x 400 kW diesel generators
2 x 100 kW emergency diesel generators
Richelieu 9,000 kW 4 x 1,500 kW turbogenerators
3 x 1,000 kW diesel generators
2 x 140 kW emergency diesel generators
North Carolina 8,400 kW 4 x 1,250 kW turbogenerators
4 x 850 kW diesel generators
2 x 200 kW emergency diesel generators
South Dakota 7,000 kW 7 x 1,000 kW turbogenerators
2 x 200 kW emergency diesel generators
Iowa 10,000 kW 8 x 1,250 kW turbogenerators
2 x 250 kW emergency diesel generators
Arleigh Burke Flight I (early) 5,000 kW 3 x 2,500 kW gas turbine generators
(the third is for backup)
Nimitz 64,000 kW

8 x 8,000 kW turbogenerators
4 x 2,000 kW emergency diesel generators

 

I don't have the numbers for King George V, Richelieu, or Littorio. Furthermore, @Azumazi can you please verify if the number for Yamato is correct?

It's interesting to note the generally high electrical power output of the American ships. This reflects the fact that compared to most others, the US Navy fielded much more powerful and sophisticated electronics and radars, as well as having turrets and Bofors mount electrically driven. For example, each main turret on the Iowa requires a total of 973 kW for the electric motors for train, elevation, shell/powder hoists, and shell rings. On the radar side of things, the SK air search radar is 250 kW, while the Mk.12/22 set for the Mk.37 directors requires ~140 kW, and the Mk.8 fire control radar requires 50 kW.

Just for a contemporary comparison, I added a modern Arleigh Burke Flight I destroyer up there as well. A modern Aegis destroyer has notoriously power-hungry radars (like the AN/SPY-1 PESA radar). I've also added a Nimitz-class carrier as well.

Edited by DeliciousFart
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Later Flight IIAs have an improved switchboard design and produce 3,000 kW per.  

Excellent info, thanks!  Wonder what the numbers would have been on some of the early turbo-electric ships.

-R

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It's also important to note whether the ship uses AC or DC power, or is mixed.  The US uses AC pretty much exclusively.  Britain uses DC.  The Germans and Japanese use a mix, but are mostly AC.

This is important particularly later in the war as electronics grew in numbers on ships.  Radar, radio, etc., all pretty much need AC power to operate.  For nations that were using lots of DC power this meant installing motor-generator sets to produce the AC for those items.  This in turn, meant that a radar or radio set had hundreds of pounds of extra weight added to provide the power that an AC electric system ship didn't require.

For the British, the choice of DC was a mistake.  They did this for two reasons on their part:  Safety and conservative design.  DC systems have been around longer than AC ones, and they are more safe in terms of electric shock hazards.  But, they also don't provide easy means to operate electronics or allow for simple electric motors.  Thus, the choice of hydraulics on many British ships for systems that are electric on other nation's ships.

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1 hour ago, DeliciousFart said:

This reflects the fact that compared to most others, the US Navy fielded much more powerful and sophisticated electronics and radars, as well as having turrets and Bofors mount electrically driven.

Surely the main reason for the much higher electric power generation is the main turrets, period. The North Carolina that you used as an example didn't ship with any radar at all (well, maybe an CXAM radar, the sources I've seen contradict each other as to whether it was added in a refit after commissioning or if it was there already) nor any Bofors mounts. The British Vanguard on the other hand had a bunch of radar sets and Bofors mounts but used hydraulics to power the mounts.

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1 hour ago, DeliciousFart said:

Just for a contemporary comparison, I added a modern Arleigh Burke Flight IIA destroyer up there as well.

A fun comparison would be to compare these stats with the output of a Ford class CVN, which uses enough power to run Vegas on a weekend. Even an Ohio class boomer can output enough power to light up a small city.

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@DeliciousFart

Littorio had about 6,987.5 kW as built - 4x 800 kW diesel generators with 10% overload capacity, 8x 450 kW turbo-generator with 25% overload capacity. All these were 220-volt. For generation of AC there was 187.5 kW split among three 62.5 kW diesel alternator groups. Degree of electrification was .169. 

Bagnasco also lists some example of other ships, a few of which disagree with your numbers, but don't give a breakdown. I'll post them anyways;

  • Iowa - 10,500 kW
  • Nelson - 2,800 kW
  • KGV - 3,000 kW
  • Vanguard - 'barely' 3,500 kW 

For Iowa at the very least, it appears he was counting emergency generators.

 

Richelieu had 9,000 kW - 4x 1,500 kW turbo generators, 3x 1,000 kW diesel generators, 2x 140 kW emergency diesel generators. The 1,000 kW generators could overload to 1,250 kW, but only for five minutes. The emergency generators could reach 168 kW for one hour.

Jordan and Dumas list some others, too;

  • KGV = 2,800 kW - 6x 350 kW turbo generators, 2x 350 kW diesel generators.
  • Bismarck = 7,920 kW - 5x 690 kW and 1x 470 kW turbo generators, 8x 500 kW diesel generators.
  • RichelieuLittorio, and Dunkerque are listed in the same place but values agree with the others

Dunkerque had 5,000 kW - 4x 900 kW turbo generators, 3x 400 kW diesel generators, 2x 100 kW emergence diesel generators. The 400 kW generators could overload to 480 kW for an hour, or 550 kW for 30 min. The emergency generators could reach 120 kW for one hour.

Jordan and Dumas also compare Dunkerque with other BBs of the era, but give no details;

  • Hood - 1400 kW
  • Nelson - 1800 kW - even more dismal than Bagnasco's rating. Possibly this is a typo?

 

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@Phoenix_jz thanks for the numbers. Wikipedia only listed 4 x 1,500 kW turbogenerators but didn't mention the diesel ones. Does the French run on DC or AC?

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Its honestly hilarious comparing these to the power generation capacity of the turbo-electric driven Battleships and (ex) Battlecruisers built by the United States during the late teens and early 20's.

I think Lexington was hooked in and used its 130,000 kW plant as a power generating station for a whole month when a city lost its grid due to a drought shutting down its hydro electric dam. That's a lot of generating capacity, especially for such a prolonged period.

Too bad the treaties killed the idea off because of the greater weight, I know the Japanese were also expressing interest in it when they ordered the turbo-electric Kamoi from an American ship builder.

Sometimes I dream of turbo-electric South Dakota's...and no I don't mean the 1920 SoDak, although that would be nice.

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I wonder if there were any differences in pumping arrangements between them as well?

Otherwise motor vs. hydraulic turrets seem to be the big difference in draw.

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4 minutes ago, Big_Spud said:

Its honestly hilarious comparing these to the power generation capacity of the turbo-electric driven Battleships and (ex) Battlecruisers built by the United States during the late teens and early 20's.

I think Lexington was used as a temporary power generating station for a whole month when a city lost its grid because of a drought shutting down its hydro electric dam. That's a lot of generating capacity.

Lexington's turboelectric drive had a 180,000 SHP output, which translates to 130,000 kW.

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1 hour ago, DeliciousFart said:

@Phoenix_jz thanks for the numbers. Wikipedia only listed 4 x 1,500 kW turbogenerators but didn't mention the diesel ones. Does the French run on DC or AC?

Unfortunately, I can't find any mention of AC vs DC, or even just a raw voltage number.

 

*edit - I asked on NA's discord server and apparently it used DC

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I'm not entirely sure of the Yamato's power supply rating, as I haven't had the chance to go over the documents that Mitsubishi found recently that was on the Yamato/Musashi's engineering spaces including the auxiliary machinery (Power systems). That rating might be from the new information which would be the best account we have. I do know they were since roughly 1924 a 225 Volt AC Current system for all Imperial Japanese Vessels.

As for why most Japanese vessel's had lower power ratings, they opted to run the vast majority of their auxillary machinery in the boiler/engine rooms off turbo-driven systems to save on power generation requirements. This means their blowers, oil pumps, and the like were all ran off turbo-generation systems. They had an electrical system to start up the first boiler to began operation of the others and had a backup system to warm up in most of their vessels boilers in case of flooding or systems being knocked out.

This concept was carried over from the Royal Navy.

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5 hours ago, DeliciousFart said:

For example, each main turret on the Iowa requires a total of 973 kW for the electric motors for train, elevation, shell/powder hoists, and shell rings.

I presume that there are manual alternatives to electric power?  I was aware that SoDak main turrets went local when power went down (2nd Guadalcanal), but did they too lose power and if so could they function at all?

 

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6 hours ago, Snowyskies said:

Surely the main reason for the much higher electric power generation is the main turrets, period. The North Carolina that you used as an example didn't ship with any radar at all (well, maybe an CXAM radar, the sources I've seen contradict each other as to whether it was added in a refit after commissioning or if it was there already) nor any Bofors mounts. The British Vanguard on the other hand had a bunch of radar sets and Bofors mounts but used hydraulics to power the mounts.

North Carolina had radar from the beginning. 

US later Battleships had electric motors driving hydraulic gears.  300hp on the Iowas, I'd suspect somewhere near that for the preceding 2 classes. 

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Hi the Japanese ships, used a mix of AC & Dc power systems. some used AC and others used DC. Not sure of the reasoning. I do know the main main turret drive on the yamato class was steam turbine driven hydraulic, around 2,000HP for each of the 4 pumps.  See attachment from the report on the IJN power systems.

Capture-1.jpg

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See attached for power data on Scharnhorst & Deutschland class. I seam to have a hard time to come by this information. I do know I have information on the eray USN turbo electric drives. Let me dig that up. - Tom

Capture-1.jpg

Capture-2.jpg

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Thank you for the information. Wow, what is up with German battleships having such a large array of generators? It just seems unnecessarily complex.

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Back up, In case some are destroyed or dammed in battle the ship can still have all the power it need to operate

 

 

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The Germans divided their electric system up oddly compared to other nations.  Some generators were for specific systems while others were for general service.  On most battleships, a "ring bus" (think  an oval race track) was used to connect all the generators through separate switchgear panels, usually one switchgear per generator.  That meant if a generator went down, another could pick up its load.

The German system, in what I'd say is typical over-engineering, went for some specific load generators, others for general service, and still others for emergency power, adding unnecessary complexity.  Wouldn't be the first time we've seen that in something the Germans engineered... :Smile_facepalm:

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On 7/9/2018 at 3:20 PM, Murotsu said:

The Germans divided their electric system up oddly compared to other nations.  Some generators were for specific systems while others were for general service.  On most battleships, a "ring bus" (think  an oval race track) was used to connect all the generators through separate switchgear panels, usually one switchgear per generator.  That meant if a generator went down, another could pick up its load.

The German system, in what I'd say is typical over-engineering, went for some specific load generators, others for general service, and still others for emergency power, adding unnecessary complexity.  Wouldn't be the first time we've seen that in something the Germans engineered... :Smile_facepalm:

I would even consider this poorly engineered rather than over-engineered; there's a difference between over-engineered and poorly engineered. Over-engineering at least implies that the vast increase in the complexity resulted in some performance advantage; for the Bismarck though, the system is practically outright inferior to those on American battleships; increased complexity yet lower power output than North Carolina and Iowa? Yikes.

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On 6/20/2018 at 1:09 PM, Big_Spud said:

Its honestly hilarious comparing these to the power generation capacity of the turbo-electric driven Battleships and (ex) Battlecruisers built by the United States during the late teens and early 20's.

I think Lexington was hooked in and used its 130,000 kW plant as a power generating station for a whole month when a city lost its grid due to a drought shutting down its hydro electric dam. That's a lot of generating capacity, especially for such a prolonged period.

Too bad the treaties killed the idea off because of the greater weight, I know the Japanese were also expressing interest in it when they ordered the turbo-electric Kamoi from an American ship builder.

Sometimes I dream of turbo-electric South Dakota's...and no I don't mean the 1920 SoDak, although that would be nice.

Yep, it ran Tacoma, Washington in Dec 1929-Jan 2930.

From: Commanding Officer.
To  : The Chief of the Bureau of Engineering.
Via : (1) Commander Aircraft Squadrons, BATTLE FLEET,
(2) Commander in Chief, BATTLE FLEET.
SUBJECT: Method of connecting ship's power to that of the City of Tacoma,
Enelosure: (A) Photographs, ten (10) views.
   
     1.    The City of Tacoma in five days constructed about two miles of high tension lines across the city to Baker Dock where the LEXINGTON moored. About two days were required to complete the connections from the dock to the ship. In making the connections to the ship, the 22-pole leads were disconnected at No. 4 after main motor, and connected to three copper bus bars, mounted vertically on insulators secured to wooden beams. The shore cables were connected at the upper end of the bus bars and were led to two 1200-ampere circuit-breakers on the dock, which in turn were connected to two sets of three single-phase transformers. Each bank of transformers was connected for "Y" or star hook-up on the low tension (ship's) side and delta on the high tension, 50,000 volt, side. This arrangement will permit use of any one of the four main generators.

     2.    The shore leads consist of twelve 750,000 circular mill cables insulated with varnished cambric and asbestos for 5,000 volt service. The banks of transformers have a combined rating of 20,000 K.V.A.

     3.    An auxiliary circuit, 125 volts D.C. with pull switches in the control room wam installed to operate the cirouit-breakers on the dock. Synchronizing lights, a synchroscope, and voltmeters were installed in the control room for paralleling the ship's power with that of the city. A kilowatt hour meter, a recording kilowatt meter and an indicating and recording frequency meter also were furnished. Direct telephone connections were made to the despatcher in one of the sub-stations for controlling the amount of power delivered.

     4.    Current transformers were mounted on the bus bars in No. 4 motor room and connected to relays in the control room for each phase, to open the circuit-breakers in case of overload. 

 


A futher safety feature was installed, to open the circuit-breakers when the generator field was opened by routine operation, ground relays or unbalanced relays, by placing auxiliary contactors on the field switch operating mechanism in a circuit to a relay. The casings of the transformers also were grounded to the ship to operate the ground relay in case of a ground in any of the transformers.

     5.    The main turbine, in order to maintain the frequency of the city, 60 cycles, must run at 1800 r.p.m. which is 45 r.p.m. above the rating. Other operating data are: voltage, 4500; power factor, 70 to 100 percent with leading current; load to date, 2000 to 13,000 kilowatts; generator temperatures, below scales of instruments; and frequency variations, less than that of the city. The turbine has been run on the governor to take a fluctuating load while the city plants have taken a constant load. No troubles have been encountered in paralleling or in other operations.

F.D. BERRIEN

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Copy to: Chief of Naval Operations
  Commander in Chief, UNITED STATES FLEET
Commandant Thirteenth Naval District
U.S.S. SARATOGA

http://www.historylink.org/File/5113

http://www.researcheratlarge.com/Ships/CV2/Tacoma/CV2_rep1.html

CV-2_05.jpg

cv-2_01.jpg

 

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For the record, your numbers for the Nimitz - class are wrong. Just add a point of correction. 

 

Also, you might want to look at what voltages each ship was generating and operating at, and maybe also include, if you can find the numbers, AC vs DC loading, since that would give a little better picture for electronics and combat systems. For example, North Carolina has two motor generator sets rated at I think 200 kw (I don't have my spreadsheet in front of me at the moment) for the radars, search lights, fire control systems, etc. 

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On 6/20/2018 at 12:26 PM, Phoenix_jz said:

 

  • Hood - 1400 kW
  • Nelson - 1800 kW - even more dismal than Bagnasco's rating. Possibly this is a typo?

 

Look at the lay down and commision time on Nelson; 

Laid Down; December 1922

Launched; September 1925

Commisioned; August 1927

 

She was a Treaty battleship, the exception allowed to RN along with her sistership during the Battleship Construction Holiday.

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On 8/9/2018 at 2:46 PM, Navynuke99 said:

For the record, your numbers for the Nimitz - class are wrong. Just add a point of correction. 

 

Also, you might want to look at what voltages each ship was generating and operating at, and maybe also include, if you can find the numbers, AC vs DC loading, since that would give a little better picture for electronics and combat systems. For example, North Carolina has two motor generator sets rated at I think 200 kw (I don't have my spreadsheet in front of me at the moment) for the radars, search lights, fire control systems, etc. 

All the available information about the Nimitz point to eight 8,000 kW turbogenerators and four 2,000 kW diesel generators. I recently got Friedman's US Aircraft Carriers book which corroborates these figures. What numbers do you have? Keep in mind that this may just be for the Nimitz when she entered service. It's possible that later ships of the class have different generator arrangements.

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4 hours ago, DeliciousFart said:

What numbers do you have?

Most likely he's not going to be able to say.  Even quoting open source material can be tricky for those who have had past access.

-R

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