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Deep in the bowels of the battleship, far below the fussily-preened decks and gleaming wheelhouse, lay the nether region of the boiler room, or stokehold. Here the grimy denizens of the Black Gang -- so called because of their dusky mantle of coal dust -- toiled ceaselessly, feeding the furnaces that powered the ship's steam engines.

Late Victorian stokers during a break from their dusty dutiesAt left, Victorian stokers relax after coming off watch; because of the exhausting nature of their work, stokers commonly worked four hours on, four off; more rapid rotations were adopted as extremely torrid conditions demanded. Gangs of stokers worked under the heavy shovel of a lead stoker who coordinated their efforts, cracking the whip when necessary and lending a helping hand if needed, plus liaising with the engineering staff. Further down in the boiler room hierarchy were the water-tenders, who maintained optimal steam production in all the boilers by regulating the water level in each one and monitoring the gauges constantly. At the bottom of the Black Gang totem pole, a crew of wheelbarrowmen shifted coal around the dusty, stifling recesses of the bunkers, delivering fuel to the firemen and shifting loads between compartments to maintain a balanced trim: hence, they were known as "trimmers" or coal passers.

Our period of study -- the 1860s through 1914 -- corresponds with technological growth and breakthroughs in the field of steam plant and engineering. For instance, the era saw the introduction of progressively higher-performance boilers and engines, ranging from the 30 psi rectangular fire-tube boilers common in the 1870s through the cylindrical or Scotch boiler good for 200 or more psi by around 1900, on through the early water-tube boilers -- Bellevilles and Babcocks -- to the three-drum models, the Yarrows and Thornycrofts, and their small-tube variants. And starting in the first years of the twentieth century, fireroom technology evolved from coal to oil firing, saving untold labor and greatly reducing the dirt and grit of navy life.

Beginning in the 1880s, the leading navies brought in systems of forced draft, under which fans blew air into the furnaces to speed combustion and increase steam production. Forced draft could increase engine horsepower by as much as 20%, adding as much as 2 - 3 knots to a vessel's speed; but the practice increased wear on the boiler tubes and could necessitate more frequent maintenance. For this reason it was used for sprints at high speed during emergencies, either in wartime or in exercises. The system described here was known as the closed stokehold forced draft. A somewhat different approach was adopted by the merchant service, known as the closed ashpit system.

Water-tube boilers had been developed beginning in the 1850s, notably the Belleville model which had been refined and improved into a very effective unit and mainstay of the French fleet by the 1890s. That decade saw a debate in the Royal Navy over the comparative benefits of cylindrical (fire-tube) boilers and water-tube types, an argument that was won by the latter camp. The Belleville of the mid-1890s and very early 1900s was the most widely accepted water-tube model, producing boiler pressures of 200 to 260 psi. Bellevilles equipped with economizers (a smaller tube assemblage that preheated the feed water) produced remarkable fuel economy for the time. Bellevilles also had the advantages of faster steam-raising and better fuel economy during slow steaming. Relatively small compared to the great cylindrical boilers, Bellevilles compensated by large numbers of smaller units. This enabled some boilers to be undergoing maintenance while under way, without sacrificing speed or efficiency.

Stokehold of the USS BROOKLYN - Belleville boilersAs the naval arms race built up a head of steam after 1898, a number of steam plant inventors and manufacturers entered the competition for lucrative defense contracts. Dissatisfied with their own Belleville installations, the British opted for the Babcock & Wilcox water-tube model or the Yarrow three-drum boiler. These latter, and the various Thonycroft models, were developed from their original destroyer boilers in which arrays of small boiler tubes bathed in the heated gases of the furnace, drawing water from a small water reservoir at the bottom of each side or "wing," and exiting in a larger steam collecting drum at the top of the firebox -- the characteristic inverted "V" shape most famous in Yarrows. Besides these commonest performance boilers, there was a plethora of models from which to choose in this period of hectic naval competition. The British and French were the most prolific boiler inventors, but the Japanese and Americans had their own variations; the Germans innovated the Dürr and Schulz models; the Russians produced the Touchov. A number of the commonest types are represented in our Boiler Room section below, with text and diagrams from contemporary technical publications. You can easily flip back to these individual pages to scope out the boilers while boning up on warships past in Big Bad Battleships' main pages. Bear in mind that this site cannot pretend to be definitive in its coverage of steam engineering in the period; there were simply too many makes and designs, all with their individual virtues and foibles. If interested in greater technical depth, with many period illustrations, the reader will find our source materials hot-linked below for instant gratification.

This page details the principal types of boiler used in capital ships. In the case of the Normand boiler, this type was developed for use in fast torpedo boats and destroyers. In the case of Yarrows and Thornycrofts', these varieties branched into large-tube and small-tube applications, the compact, small-tube installations being used in TBs and destroyers and the larger models used to power battleships, armored cruisers, and other large warships. For a peek at some of the commonest destroyer/TB boilers, visit our Small Speedy Boilers Page.

As Denis Griffiths has observed:
Coal-firing of boilers had many disadvantages, but there were no real alternatives until the commercial exploitation of oilfields came about during the latter part of the nineteenth century. In 1888 Admiral [Sir John] Fisher stated that the use of oil fuel would increase the Royal Navy's efficiency by 50% and although there were skeptics, some experimentation did take place. The destroyer Surly was fitted out for oil fuel trials in 1898, and more detailed investigation took place between 1902 and 1905 when an in-depth research programme was carried out at Haslar, ultimately leading to the conversion of the fleet to oil-firing a number of years later. Fisher's arguments in favor of oil fuel included increased performance and endurance, easier stowage and transportation to the boilers, ease of refueling, [reduced] manpower required [in fueling], better response to the demand for steam, and improved availability of supplies overseas.

-- from Warship Machinery, in Steam, Steel and Shellfire (London: Conway Maritime Press, 1992), ed. Robert Gardiner.

Coaling a Dreadnought

Coaling a German dreadnought, circa 1910

Crewmen refuel the early German dreadnought Nassau, c. 1910. Shoveling coals dumped on deck from the coal barge alongside into burlap sacks (left), they transport sacks on handtrucks and dump coal down the chutes against the superstructure bulkhead at center -- dark blankets rigged to localize coal dust. The fuel thunders into the bunkers far below decks, to be redistributed by crews with wheelbarrows. Enlarge With the coming of liquid fuel, the scrape of shovels and clamor of coal dropping four decks down gave way to the whine and throb of pumps and the silent flexing of hoses, overseen by a few aproned technicians at either end; the incessant labor of the stokehold gave way to a relatively clean and clinical operation.

Representative Types of Boiler

Rectangular Boilers

Cylindrical Boilers

Belleville Boilers

Mumford Boilers

Niclausse Boilers

Lagrafel d'Allest Boilers

Babcock & Wilcox Boilers

Dürr Marine Boilers

Normand Marine Boilers

Yarrow Boilers

Thornycroft Boilers

Miyabara Boilers

Decorative motif
Servicemen stoking boilers aboard transport USS GEORGE WASHINGTON, c. 1918
American servicemen stoke the boilers of the transport George Washington ("Big George"), c. 1918.

Pertinent Pages