The American aircraft carriers Lexington and Saratoga were built in the 1920s, converted from the unfinished hulls of battlecruisers made redundant by the Washington Naval Treaty of 1922. One of their innovative aspects was a relatively new kind of engine, the turbine-electric. Rather than driving the propellers through a series of gears, the steam boilers in the Lexington and Saratoga drove electrical generators. The electricity then powered electric drives in the rear of the ship which turned the propellers. This new set-up was supposed to have advantages of economy, efficiency, the ability to reverse the propellers quickly, and better low speed operations. Popular Science proudly labeled the new engines as a “major revolution in shipbuilding.” [1] The Society of Naval Architects and Marine Engineers agreed:
The fact that the last nineteen capital ships of the U. S. Navy are or will be equipped with the electric drive is sufficient testimony in behalf of what the builders and users of war vessels think of its merits. The prime requisite of reliability in any type of machinery designed to propel war vessels was recognized in the electrical machinery at the time of the first installation. Also the calculations showed that the unit fuel consumption over a wide range of operating speeds should be better than anything yet proposed. Service operation of two 30,000-horse-power electrically propelled battleships has indisputably proven that the reliability is all that was claimed, and that the fuel economy, as compared with other ships of the same type using direct-connected turbines with geared cruising turbines, is vastly superior.
Two other factors in which the electric drive shows a marked improvement over other drives have been emphasized since the first battleship was built, namely, the superior protection from torpedo attack afforded the machinery by virtue of the arrangement of the electric plant and the superior maneuvering qualities of the electric drive. The large horse-power requirements of the present war vessels (60,000 horse-power and 180,000 horse-power) preclude the use of reciprocating-engine drive, and this leaves electric drive with a decided maneuvering advantage over any other form of turbine drive. [2]
This turned out to be optimistic. The advantages noted were offset–as the Navy was to discover in WWII–by problems. The turbine-electric propulsion systems were more vulnerable to shock damage than ordinary, geared engines, flooding of the engine compartment required time-consuming and expensive repairs, and the power/weight ratio of the turbine-electrics was much worse than of conventional engines. [3]
But that was in the future. As built, the Lexington was essentially a large power plant with a side helping of warship. Each of its four electrical generators could put out 35,200 kilowatts, in total “enough to supply the electricity demands of a city the size of Philadelphia.” [4]
Strangely, as it turned out, the Lexington served as a power plant long before she saw a day of combat.
(Part II coming on Monday)
The Edge of the American West 
12 comments
February 12, 2010 at 11:56 am
Erik Lund
Okay, I’ll bite.
It would seem on first principles that an oil>emf>mechanical work cycle would be less efficient than oil>work. The problem was that steam turbines ran at far higher speeds than was efficient for propellers.
Fisher introduced turbines in _Dreadnought_ famously (in retrospect) because they gave a few more knots speed. At the time, and I think that this is the real key to understanding the “_Dreadnought Revolution_,” the change made significant labour economies possible, and, perhaps as a second-order effect, reduced certain systemic distortions in the Royal Navy labour force by eliminating stokers (as a work classification, as opposed to a rating.) I’d dilate on why I think that is _very_ important, and still a lesson worth considering for those committed to social justice, but I haven’t shaken out the argument to see if it will reallly fly.
Anyway, that left _Dreadnought_ with highly energy inefficient direct-drive turbines. The solution is some kind of gearing mechanism –which is really what the electrical interposition in _Lexington_ is. However, an even more efficient interposition would be mechanical gearing. You only have to wrap your head around gears capable of taking a hundred thousand horsepower. Is such a thing possible? With reservations, it is. (Again, if anyone cares, I can point you to some interesting period articles, although this is the kind of project that research librarians in engineering libraries can reallly get behind, and some of them are pretty cute.)
Perhaps the salient point is that I know some engineers educated in the 1950s who came out of the experience actually believing the hype that Silbey cites here: turboelectric was the standard operating procedure for steam-powered warships going forward.
Why is it salient? Because GE and Westinghouse did such a good job of promoting a clearly mistaken technological option on this continent. How _that_ came to happen would be an interesting question for some researcher.
February 12, 2010 at 12:16 pm
docdave
Eventually, even Union Pacific drank the turbo-electric koolaid: witiness the “Big Blow” turbine-electric locos of the 1950s and early 60s. They drank Bunker C like fish, were loud enough to be banned from operating in Los Angeles and apparently had a flame-out problem when operated in tandem through tunnels. Quintessentially guy-engineered, as my librarian wife (who is ‘way savvy in such matters, having watched me do too many domestic re-engineering projects) has noted. Of course, UP, the Railroad Different, even tried to make one run on coal.
In theory, though, the turbo-electric drive for the Lexington is attractive: fewer honker-sized gears, shafts and connecting rods than with conventional drive, hence improved efficiency compared to the mechanical interposiotion of a reduction gear train. Need to economize? Shut down one of the dynamos (assuming that the Lexington had multiples of these).
Bottom line? Tom Swift would have been able to make this system work–and turn a profit, probably.
February 12, 2010 at 10:06 pm
TF Smith
I went from Phoenix, Arizona, all the way to Tacoma….
Interesting (non-scholarly) piece on the USDN’s turboelctric capital ships of the ‘teens…
February 13, 2010 at 6:20 am
kid bitzer
during the teens, the us navy also tried using more eclectic turbos:
http://en.wikipedia.org/wiki/USS_G-3_(SS-31)
February 13, 2010 at 4:36 pm
Robert
My grandfather was an electrician during the Second World War and served on the Saratoga during the wars endgame. Among other things he helped maintain the turbine-electric engines.
February 13, 2010 at 5:19 pm
silbey
@Robert: That’s excellent. Did he ever talk about it?
February 13, 2010 at 5:58 pm
Robert
@sibley, He talks about it at every Thanksgiving. He took part in preparing the Saratoga for the Bikini Atoll tests. I think he has some photos and a book made for crew.
February 14, 2010 at 9:25 am
TF Smith
KB –
Diesel-electric was the standard for submarine propulsion systems for most of the 20th Century; diesels were used on the surface, both for propulsion and charging the batteries, and the batteries, of course, were used while submerged.
Or did I miss something about Turbot? Although Felix X. Gygax is just an awesome name…
I thought you were going to link to one of the steam-powered sub designs.
Silently yours…
February 14, 2010 at 9:43 am
Jonathan Beard
I do not fully understand Erik Lund’s comment. What is the link between the introduction of steam turbines in the Dreadnought and the elimination of stokers? The Dreadnought was coal-powered, just as were many later British battleships and battle cruisers. The replacement of coal by oil-fired boilers did result in major savings in crew, but it came later. There were certainly many ships in World War II–freighters, anyway–using triple-expansion engines and oil.
The British decision to change to oil was complex, and there is some information here.
http://wapedia.mobi/en/Dreadnought?t=3.
Jonathan
February 14, 2010 at 9:46 am
Jake
I don’t know how much the train example shows. Virtually all locomotives these days are diesel-electric; gas turbines were horrible because they scale down poorly, have horrific part-throttle performance, and locomotives do not need to be particularly light. By contrast, most warships these days use gas turbine with mechanical reduction gearing, because they make a lot of power in a small space and if you install four of them you avoid having to run them at 25% throttle.
Rather than some corporate conspiracy, I wonder if it wasn’t just an issue of the technology not being fully matured at that point. I don’t think the nature of shock damage was fully understood until the end of WW2, for instance.
February 14, 2010 at 11:30 am
kid bitzer
tf smith–there’s always less to my comments than you can imagine.
i was just struck by your spelling of “turboelctric” in your 10:06.
February 14, 2010 at 11:44 am
Erik Lund
Jonathan Beard has a point. _HMS Dreadnought_ was a coal-fired ship, and therefore required stokers. I have a more complicated (or more incoherent) point to make. Let’s see if I can.
First, sources:
World War One Net has some digitised articles from Brassey’s, including http://www.gwpda.org/naval/brassey/b1904a00.htm.
There’s a certain amount of industry buzz here, but it should be clear at least that replacing triple-expansion engines with turbines significantly reduced stoker menial labour burdens other than actually shovelling coal. Notice the attention to gas engines!
Unfortunately, the same source has neglected the articles on Royal Navy manning that can be found in contemporary Brassey’s. Here’s an enthusiast’s take on Fisher’s reform of the Royal Navy Engineering Branch. Ignoring his editorialising on the Selborne Scheme, note the discussion of the more important Cawdor Memorandum immediately below.
http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/Training_&_Recruiting/Selborne_Memo.html
So, in short, in 1904, Stokers were a higher-paid branch of RN ordinary ratings. The pay was justified because they did particularly heavy labour, and, more importantly, worked in the extremely difficult conditions of warship engine rooms.
Incidentally, stokers performed many mechanical duties that might also be performed by commissioned engineers. Even if his scheme for reforming the corps was mistaken, Fisher could see that the Admiralty was making poor use of its commissioned engineers. Wherever they went and did instead, engineer officers should not be oiling valves in their 30s.
To see why this is a problem, consider mobilisation for war. The Russians have, in a dastardly, underhanded move, occupied Crimea. Now the Navy needs to kick them out. All the warships on ordinary are commissioned, the Dockyards go on full time, and men are needed for them. So one calls Petter’s and asks for all the engineers the firm can spare, for a bit of adventure. One gets a selection of mid-career engineers, for whom there are many billets.
For example, one 40 year-old engineer might be called upon to rebuilt a mine-wrecked battleship’s engineroom down in a forward anchorage. Another might be needed to …..carry an oilcan around a second-class cruiser rusting in Singapore?
That’s no way to run a navy. A Commander (E), RNVR ought to have a clear set of duties appropriate to grade and experience.
The focus on the Selborne Scheme, however, obscures the importance of fixing the problem from the stoker’s point of view. A senior stoker was the substitute for the ship engineer who made the duties of the commissioned officer so uncertain.
He was, in effect, an engine room straw boss, diagnosing and directing maintenance and repair projects. A battleship would have such a man, but a destroyer might well not, and there was no organisational way of determining, from the outside, which might be the case.
In the normal way of doing things, there would be. As a stoker advanced in age and experience, he would be recognised by pay raises, and perhaps giving him a nice title, promoting him from Associate Stoker to Assistant Stoker to Full Stoker, for example.
Unfortunately, those promotions (and pay increases) would neatly track his declining ability to perform actual stoking duties! (Suddenly my analogy above doesn’t seem that distant….) Not only that, but a workforce structure in which strong young men are paid disproportionately large amounts means that the Navy is out on the market aggressively recruiting and retaining strong, tough young men. As a result, its seniority pyramid contains a large number of young men selected for strength, men who cannot be selected out as they age without adversely impacting hiring.
The problem is familiar from agricultural field labour. Young men start at high wages, and find their earning power gradually declining as they age. If one wishes to retain the most intelligent and ambitious recruits for later duties requiring intelligence, skill and diligence rather than strength, these characteristics have to be recognised, even cultivated, early, or they will see the handwriting on the wall and leave.
The solution is to focus the “stoker” on the most important and challenging aspect of the duty, and relegate the less important but more arduous one. In this case, the stoker will turn into a machine tender. Someone, or something else, will have to do the actual stoking, perverse as it seems.
Fisher’s interim solution was to rotate deckhands through the engine rooms. It did not work very well. Fortunately, it did not have to, as more radical solutions (oil, powdered coal, and gas) were in sight.
The same logic applies to guncrews, and, in the civil sector, puddlers. And the “other” solution to the problem is the welfare state.