The capital ship bottleneck – heavy guns and their mountings

heavy guns and their mountings
Follow me on

Matthew Wright

Check out my best selling works at Amazon
I'm a New Zealand historian with a life-long interest in matters military, particularly naval engineering. My books have principally been published by Penguin Random House. I'm a Fellow of the Royal Historical Society at University College, London.
Follow me on

A fair number of heavy ships built worldwide over the last century or so were delayed – or compromised in some way – because of limitations in supplying heavy guns and their mountings. This proved to be the capital ship bottleneck , slowing or even outright changing construction.

heavy guns and their mountings
The colossal 16.25-inch mountings fitted to Benbow (1888) and, later, the Victoria class (1890). Public domain, via Wikipedia.

Every nation hit the problem at one time or another. It held up some battleships and forced others to be re-designed, such as Benbow, one of Britain’s ‘Admiral’ class of the mid-1880s, which was fitted with two Elswick 16.25-inch guns because the smaller 13.5-inch weren’t going to be available within the three year build-time stipulated in contracts with the Thames Iron Works. And then the ship was delayed waiting on the 16.25-inch weapons.

Even when the British arms industry was ramped up, gun and mounting construction was a limit. HMS Dreadnought could be built in 14 months spanning 1905-06 (not the year-and-a-day of propaganda) in part because work on her five twin 12-inch mountings was accelerated at the expense of the two each being built for the Lord Nelson and Agammemnon (many references claim these guns were directly appropriated, but apparently that’s a myth). A decade later, the battlecruisers Repulse and Renown were designed with just six Mk I 15-inch weapons, partly because guns and mountings for eight each couldn’t be completed inside the specified 15-month build time.

Britain’s arms industry declined after that war, and one of the consequences was that they had to build five 14-inch gunned King George V class in the late 1930s. Early plans to build just two and then jump to a larger 16-inch gun design failed because of the time taken to develop the larger weapons and mountings.

the capital ship bottleneck
HMS Benbow in magnificent Victorian era black, white and buff livery. Public domain, via Wikipedia.

Even the United States, with its superior industrial capacity, ran into problems, as in 1910-11 when the Naval General Board wanted new battleships with ten 14-inch guns, but where 12-inch gunned ships had to be built because the larger weapons were unavailable in the time.

the capital ship bottleneck
HMS Royal Sovereign (1891), high-freeboard and with barbette mountings. Public domain, via Wikipedia.

The other problem was mounting heavy guns. Early ironclads of the 1860s followed ‘wooden wall’ tradition by mounting their guns broadside on a gun-deck; but as the scale of armour and armament increased the number of heavy guns dropped, into which flowed the problem of shooting in any given direction. One solution was the turret, invented in parallel in Britain by Cowper Coles and in Sweden by John Ericsson. Turrets consisted of rotating armoured mountings that carried armour, guns and ammunition. But they were heavy, and the displacement-limited battleships of the later nineteenth century paid a penalty with low freeboard. The lighter solution was a French invention, the barbette, a fixed armoured tube, into which was fitted a lighter rotating mounting for the guns.

Initial barbette mountings offered no above-deck protection to gun crews. Barbettes with armoured gun-houses began appearing on British battleships from the mid-1890s, by which time breech-loading guns were standard.

heavy guns and their mountings
Animation of a Mk I 15-inch mounting and barbette, with ammunition pathways. Note that the propellant store is above the shell store, a pattern reversed later. Public domain, via Wikipedia.

Systems to let guns load at any angle and elevation were slow to arrive. Britain’s Majestic class of the 1890s required the guns to return to fore-and-aft before munitions lifts and rammers were aligned. To get around that, stowage for limited ready-use ammunition was provided within the gun-house with an auxiliary rammer, meaning the guns could remain on target until local munitions were expended.  But even as late as the 1920s, many ships – across a range of navies – could still only load at certain angles of elevation, which increased time between salvoes.

Adding more guns to the mounting added other complexity; twin turrets emerged early, but triple mounts for heavy battleship guns were not developed until the early twentieth century, first deployed by the US Navy. Although designs were on the drawing board in the First World War, quad heavy gun mountings did not enter service until the 1930s, when the French deployed them on their Dunkerque class. Into this fed issues of protecting against flash, which could migrate down a munitions shaft and trigger a magazine explosion. All of this added engineering complexity. The result was that guns and their mountings remained relatively expensive, complex, and difficult to build, right to the end of the battleship era.

Click to buy

Don’t forget to check out my book Dreadnoughts Unleashed, available on Kindle. Click to buy.

Copyright © Matthew Wright 2017


Please enter your comment!
Please enter your name here