I've been searching for this for days, but cannot find it. What is the weight of a typical boiler on a WW2 US Navy ship?

Example: Fletcher Class DD had a total weight (displacement) 2100 to 2500 tons and carried 4 boilers built by Babcock and Wilcox, each of which produced 600 psi steam from operating temps of 850 F. But it does not mention weight, and I can't find any model number to look up either.

Babcock and Wilcox seems to be the dominant boiler company for USN ships. The Baltimore Class Cruisers had them, as did the USS Essex CV-9. If everything from DDs to Carriers used them then I think it's safe to say they were dominant.

So it's strange I can't find any model numbers and details. Decent sites I've found but don't say weights:



https://kbismarck.org/forum/viewtopic.php?t=8969 (This thread looking for the same thing, very depressing someone mentions two books about boilers that do not give weights. I also looked thru history.navy.mil to no avail.)



Those last two actually have a lot of line drawings, however I cannot find a list of weights anywhere in them, not even the more generic weights of lightship or deadweight.

That list of sites is by no means exhaustive of my search efforts, just the best ones found so far.

Why do I want to know the weight of a boiler? Well because they look pretty huge and heavy. If those things total up to hundreds of tons...I mean imagine how much weapons and fuel you can't have due to that extra weight. A 5 inch shell and its powder seems to be about 40 kg. If you had an extra 100 tons, that represents 2,500 more rounds of ammo you could carry. Same story with fuel, and other weapons and ammo. So this sort of thing is important for logistics.

  • 3
    I mean imagine how much weapons and fuel you can't have due to that extra weight - without that weight, the ship's not moving so any additional guns and ammunition are pretty much useless unless the enemy comes to you. The boilers were as heavy as they needed to be to do their job safely (to avoid exploding and killing everyone).
    – Steve Bird
    Commented Aug 10, 2021 at 22:00
  • I assume you are acquainted with Drachinifel :D youtube.com/watch?v=Qveycr0-WMU
    – rs.29
    Commented Aug 11, 2021 at 7:50
  • In pure displacement terms, the WP article has a diagram of the hull - the two boiler rooms each take up about 10% of the hull space, so you could estimate about 5% of displacement, 100t+, per boiler. All very approximate but gives you a sense of what the answer might be. But @stevebird is right that thinking of these as "extra weight" is a mistake - speed was very much a primary requirement for destroyers, which meant large allocations to boilers & engines. Commented Aug 11, 2021 at 10:16
  • @SteveBird "The boilers were as heavy as they needed to be..." That's fine. So how heavy were they? Or how heavy did they need to be?
    – DrZ214
    Commented Aug 11, 2021 at 21:52
  • @rs.29 Watched the 37-minute vid and nowhere did i hear a single mention of weight---i mean a stated weight in tons, pounds, something else. Not for an old era boiler, not for a 1900 or WW1 boiler, not for a WW2 era boiler either. I have watched Drach before and i gotta say im disappointed. I expected better info with actual numbers.
    – DrZ214
    Commented Aug 11, 2021 at 21:54

3 Answers 3


According to a site dedicated to the USS Oklahoma City CL91 (a light cruiser of 11,744 tons), she had four Babcock and Wilcox Express Type double furnace (M-type) boilers, with the following details

Each boiler weighed 157,850 pounds dry weight. It held 17,810 pounds water, giving a total wet weight of 175,660 pounds. The boilers had 7471 sq. ft. of heat generating surface, in 1820 saturated generating tubes, 224 superheater tubes, 66 water wall tubes, and 62 economizer tubes. Furnace volume was 1158 cu. ft. with 430 sq. ft. of refractory surface (firebrick and diatomaceous earth blocks). The boilers measured 23' 5" wide, 18' 1" high, and 16' 3 5/8" deep.

So dry, the boilers were about 79 (short) tons each.

  • This is the most detail I've ever seen in a free website, and it has references at the bottom. Thank you very much for that. One question. Do you know what "express type" means for a boiler?
    – DrZ214
    Commented Aug 12, 2021 at 1:08
  • The "express type" used smaller diameter tubes to give a greater ratio of tube surface heating area to the tube volume, thus more rapid steaming.
    – Steve Bird
    Commented Aug 12, 2021 at 6:17

Found a source on Russian Wikipedia article for the Fletcher Class Destroyers. Using google translate, it says,

The propulsion system repeated the layout of the "Glives" type - it was a high-temperature medium (43 bar [9]) pressure unit , which theoretically provided 20-30% higher efficiency than modern designs of the overwhelming majority of foreign destroyers [10]. The payment for this was the large mass of the power plant, which amounted to 787-822 dl. tons 1... The fuel supply was 491 dl. tons of naval fuel oil and 40 tons of diesel fuel.

"dl. tons" means long ton, which is 1,016.047 kg. The short ton is 907.18474 kg.

So that 1 leads to citation: N. Friedman. U.S. Destroyers. — Annapolis, MD: Naval Institute Press, 2004. — 489 p. — ISBN 978-1-55750-442-5. And it also said it was on page 412.

However, I can't find this book on google books or anywhere else available online, and on stores it is pretty pricey. I suppose I could start hunting in libraries but maybe someone here will have useful comments about it.

Also, note the exact language "the power plant". This would include the boilers and the steam turbines. But probably not the shafts and screws. Anyway, if accurate this means a single boiler and a single steam turbine has a total weight of about 200 long tons (203 metric tons).

  • The "power plant" would also include the condensers which turned the low pressure steam exhaust from the turbines back into liquid water to be recirculated to the boilers.
    – Steve Bird
    Commented Aug 12, 2021 at 12:34

Heavy is relative. The temperature and pressure listed would be pretty routine, today pressures ( power) are higher, like 1000 psi. Likely the shell/fire box is less than one inch thick. Most of the weight is in the tubes ; thousands of feet of 2 to 4 inch diameter tubes with wall thickness of roughly 0.3 to 0.4" wall thickness. There would be a mud drum ( same roughly one inch wall ). There will also be a couple other drums like a superheater. So the weight is distributed in several components. There are different designs like "fire wall tubes" (water wall). It seems there must be diagrams of boilers on the net that could be more specific. Every power station and refinery has several boilers , likely similar to marine boilers.

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