What was required to move a battleship?

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Hey guys!

I'm doing a little research into wwii battleships and how they worked.
Now I'm stuck at what happend when the captain ordered a new speed with the telegraph.
Lets say he orders a increase in speed with 5kt, what happens in the engine and boiler rooms?
As far as I understand you need to open up a steamvalve to let more steam into the turbine which will spin the shaft/propeller faster.
Then I just assume that some other guys have to increase the flow of seawater and oil to the boilers!?
What else did the crew have to do to increase the speed of a battleship?

Any insight would help me alot, because I have no idea!
Cheers!

[Sailor Steve]

It's been eight years, but as I recall during our visit to USS Texas in 2008 this was explained to us. The first thing that happens is an increase in boiler pressure. Once this is accomplished the signal is sent to the engine rooms, and engine speed is increased. If the engine speed change is attempted first it can create a vacuum in the boilers which can put the fires out. Not a good thing.

Other than that I don't think there's much more involved. Everybody knows what pressure and what revolutions are necessary for a given speed, and once the order is given they just do their jobs.

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Great!
Thanks alot Steve!

It would be interesting to see what is required to start up a ship like that, and how long time it would take.

[CaptBones]

Let me take a shot at answering this; having been Engineer Officer (often incorrectly called “Chief Engineer”) of two USN oil-fired steam ships (USS KIRK and USS TARAWA), a member of the Pacific Fleet Propulsion Examining Board, and the Director of Propulsion Engineering “A” Schools at Great Lakes, I have an idea of how it worked.

Regardless of whether it’s a battleship, an aircraft carrier, a cruiser, a destroyer, or any other type of “conventional” (oil-fired) steam ship, the propulsion plant works essentially the same way. And BTW, there is never ever seawater used, deliberately, in a steam propulsion boiler. Next to the propulsion engines and electrical generators, one of the biggest “consumers” of the steam produced in the boilers is the distilling plant, to provide distilled water for the boilers.

Before the introduction of automatic boiler controls and automatic combustion controls, changes to the firing rate of the boilers had to be done manually. The firemen (or Boiler Tenders in the WWII USN) would cut burners in or out and adjust the flow rate of feedwater and combustion air to the boiler as the steam demand changed. In older ships, like the TEXAS, that had to be done before the throttles were changed, opened or closed, in the engineroom. In ships built during or just before WWII, the throttles could be opened or closed at the same time as the burners, air registers, feedwater valves, feedwater pumps, and forcer draft blowers were being adjusted. Boilers of that era were called “Express Boilers” because of the high flow rates and the speed with which adjustments could be made.

When the engine order telegraph signaled a change, the throttlemen would begin turning the valve wheels, slowly, to increase or decrease the flow of steam to the high-pressure turbine nozzles. At the same time, the BTs would either cut additional burners in or shut them off, as needed, adjust the air registers, the feedwater supply valves and adjust the feedwater pumps and forced draft blowers, if necessary. Depending on the type of boiler, the BTs might have to cut burners in or out for both the main furnace and the superheater; some designs only required one or the other set of burners to be cut in or out, the other set had a range of adjustments for the fuel oil flow and air flow (called the “turn-down” range) that could accommodate the normal changes in steam flow rate.

One of the tricks to controlling the water flow to the boilers is that the water level in the steam drum will change immediately in reaction to the change in steam pressure in the drum and compensating for that change is exactly the opposite of what the final adjustment needs to be. That is, when the throttles are opened, the drum pressure decreases and the water level in the drum rises. The feedwater flow has to be reduced to keep the water level from rising too high (bad things will occur if that happens). After that, when the water level begins to drop, the feedwater valves need to be opened to admit the increased flow of feedwater that the higher steam demand requires. The opposite is true when the throttles are closed.

Now, all of this can be nicely “tempered” by an experienced and considerate Officer of the Deck (OOD) or a Commanding Officer who puts an appropriate note in his Standing Orders. A good OOD or conning officer will advise the Engineering Watch of expected speed changes or a forthcoming evolution that will require frequent speed changes. The engineers can make preparations for that.

As for starting up a steam plant…that is a fairly straightforward evolution, but can be dependent on a lot of outside influences and variables. Prior to and during WWII most large ships would never be “cold iron” in port. Being in the engineering department in those days meant frequent weekend duty, but at least you didn’t have to stand Deck Watches. The reason the NEVADA was able to get underway during the attack on Pearl Harbor, is because the Engineering Watch was preparing to change over the inport steaming boiler and had two boilers available to answer maneuvering bells within minutes.

Here’s a somewhat condensed and simplified explanation. If you were “cold iron”, the plant startup would begin several hours before the ship was scheduled to get underway. Small ships (with small boilers) could do it in two or three hours, big ships would need six to eight hours. Preparation could require activities a day or so earlier, depending on the circumstances and condition of the plant; including such things as whether or not sufficient shore steam and water are available or if the ship’s feedwater tanks and de-aerating feed tanks are filled or not…water is the key.

With those older boilers, when everything was ready the actual light-off was fairly simple, but almost comical. You opened a burner assembly and put in a couple of oil-soaked rags and scrap pieces of wood and set a match to it; then closed the burner, opened the air register and cut-in the fuel oil…whooosh! “Fires lit in (number) boiler!” Memory lapse here! That really applied to boilers prior to the mid-1920's and early 30's; mostly ships converted from coal to oil...almost all marine boilers since the late 20's were equipped with light-off ports in one or more of the burner assembly front plates. We actually had to do it that way once during Casualty Control Drills in Tarawa...talk about a "Keystone Cops" evolution! In more modern boilers, you have the pleasure of being able to light off by inserting a torch through a special aperture in the burner air register front plate. I've had the excitement of getting a "blow-back" in the face during that evolution...lost every hair on my head...young enough then for it all to grow back though!

As the heat in the furnace built up and it began to produce steam, the auxiliary steam stops would be opened to supply the forced draft blowers and feed pumps. Once those were rolling and supplying more air and water to the boiler, the steam pressure would build rapidly and then you could open the main steam stops and begin rolling the generators. Once the generators were supplying correct voltage, you could shift the electrical load from shore power to ship’s power and shift any motor-driven pumps in the plant to steam driven pumps. After that, it was a short time until full steam pressure was available to answer all bells.

Hope this helps…

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Thank you CaptBones!
Very detailed and definitly helpful! I don't understand half of it yet, but I will read it through properly a few times.

Alot of questions will arise, I have a few already that I hope you don't mind:
Feed water, is that the distilled water? Did you bring that from land or is it processed sea water?

When cruising, did you ever keep a high temp/pressure just to be able reach maximum speed fast in case a situation arised?
Or was the pressure allways adjusted according to speed to save oil?

Thanks again!

[CaptBones]

Feedwater is distilled water. A steam ship must have enough distilling plant capacity to feed the boilers and provide potable water for the crew. The boilers require much more water than the crew. The storage tanks are segregated and if the water in one of the feed storage tanks becomes slightly contaminated, that water can be transferred to the potable water tanks; the boilers need water that is more "pure" than the crew needs.

Before lighting off the plant in port you can fill or "top off" the feedwater tanks from shore supply, usually tanker trucks; but some shore stations had feedwater piped to the piers and you could hook up by hose connections. Once underway you were on your own and dependent on the distilling plant. Distilling seawater is very simple, it just takes heat. Even a small ship uses thousand of gallons of feedwater a day; the two distillers in the KIRK produced 12000gallons a day and both were running most of the time. If one went down for some reason, the crew would be put on "water hours" (strict rationing) until it was fixed.

Once the plant is on line and ready to go to sea, the pressures and temperatures in the steam system are always the same, based on the boiler steam drum and superheater "set points" and various regulators to supply auxiliary steam and "Hotel" steam. Changes in speed (or even electrical load) are adjusted for by increasing or decreasing the boiler firing rate to increase or decrease the volume/flow rate of steam being supplied to the main engines and turbogenerators...the boiler(s) should always operate at the same pressure and temperature...the "set points". Burning more fuel or less fuel does not change the pressure or temperature in the steam system, it changes the amount of water converted into steam.

Back in WWII that was not the case in some ships. The steam pressure was maintained at a constant value, but the temperature could be adjusted coming out of the superheater...cutting burners in or out.

The capability to respond rapidly to speed increase demands is dependent on the number of boilers on line; or, in those ships with variable superheater outlet temperatures, by cutting burners in or out (we still had a few of those around in the 60's and 70's for guys like me to get trained on). Modern steamships were built with a fewer number of larger boilers and combustion control systems that made it possible to cruise economically on one or two boilers, but respond quickly to high speed demands without having to bring another boiler on line right away. "Full power" was the only time you really need all boilers on line and that very seldom happens without plenty of advance notice.

In WWII...economical cruising was not generally a big concern...you had the number of boilers on line that you would need to respond to any expected speed demand. Ships in a Task Group or Task Force refueled alongside an oiler every three or four days to keep at least 85% fuel onboard; we continued doing that in peacetime. Even nuclear aircraft carriers did that...keeping aviation fuel "topped off" every few days.

Hope this helps some more...

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That was a great read!! Thanks again!

I'm working on a little simulation, but it's based on german wwii engines, not alot of info to be found on their components...

I see on some plans of german steam-turbine ships that they also had a small diesel engine room or "diesel dynamo", any idea what that was for?

[CaptBones]

Steam ships built since at least the 1930’s and even earlier, had an emergency diesel generator. Warships all had at least one, most had two, one forward and one aft. Many steam powered warships had ship service diesel generators in combination with, or even instead of, steam turbogenerators. The diesels could be equipped to do an emergency “black start” in 10 seconds. That’s essential if your steam plant goes “hot and dark”.

In the event of a machinery casualty or damage that causes the steam plant to shut down, you need an alternative source of electrical power to re-start the plant and to provide power to the rest of the ship while the steam plant is being restored. Modern steam plants use electric motors for many auxiliary pumps, including the pumps and blowers for lighting-off the plant from a cold-iron condition. If you were in port and connected to shore power, you used the shore power to run the fuel pumps, feed pumps and forced draft blowers needed for light-off. Once auxiliary steam was available you would shift to the steam driven pumps and blowers. Obviously, if you suffered a casualty or damage that shut the plant down at sea, you couldn’t run a cable back to shore power, so an emergency generator was necessary. Diesel generators were the best choice; they’re rugged and reliable and very importantly, the fuel wasn’t gasoline.

If you research German WWII warship propulsion plants, you’ll find that they had some very advanced high-pressure steam plants, including some equipped with “P-fired” or supercharged boilers that used the boiler exhaust gases to drive gas turbines that powered the forced draft blowers. The USN copied several of those types of high-pressure plants and introduced them in many classes of ships during the 1950’s, ‘60’s and early ‘70’s. Most of those plants operated at 1200 psi 950F, compared to the typical WWII plant at 600psi, 850F. I made my 3rd Class Midshipman Summer Cruise aboard the Navy's first P-fired ship, USS GARCIA (DE-1040) and the KIRK had a 1200psi plant with one ship service/emergency diesel generator (SSEDG). The TARAWA was a "Super 600" plant, 600psi, 850F, but with totally automated boiler controls and combustion controls (also the largest marine boilers ever built). She had two emergency diesel generator (EDG) sets, one forward and one aft; the forward one also drove the bow thruster through a mechanical drive, the generator was declutched when doing that.