Plan Z:
Britain’s Vanguard
by Mike Bennighof, Ph.D.
October 2021

Dismayed by delays in constructing the King George V class battleships, in 1939 the Royal Navy sought to obtain at least one additional fast battleship quickly. The Lion class appeared promising, but their new 16-inch guns would require a great deal of testing before they could be manufactured; these ships could not be rushed forward easily.

Stanley V. Goodall, the Director of Naval Construction, had prepared an alternative. In February, 1939, design work began on a large 30-knot ship to make use of armament that could be guaranteed to work: the 15-inch Mark I of pre-Great War vintage. The Royal Navy had taken delivery of 184 barrels, and these weapons would rotate between the ships that mounted them (by 1939, ten battleships, three battle cruisers and an assortment of monitors) and depots that refurbished them when a ship was refitted.

When Courageous and Glorious began reconstruction as aircraft carriers in 1924, their turrets went into storage and the gun barrels rejoined the general pool. The new fast battleship would make use of these turrets to speed construction. By July, three designs had been presented but work stopped with the outbreak of war. It resumed in February, 1940, and after a number of false starts an order was placed in March, 1941.

The design appeared promising, and the Sea Lords discussed building a second ship to it using the turrets from the battleship Royal Oak, which had been sunk in Scapa Flow in October 1939 by a German submarine. Though the wreck lay in relatively shallow water, salvage appeared difficult and the discussion moved on to her decrepit sister Revenge, which appeared to have very little remaining military value. Removing her turrets for use in a new fast battleship appeared to be a better use of available resources; Revenge could then be converted into an anti-aircraft guard ship or scrapped.

Another proposal would have used the eight 13.5-inch Mark II turrets which had been removed from the battle cruiser Tiger and battleship Iron Duke and placed in storage when they had been scrapped and converted into a training ship, respectively. Mounted in a smaller version of the new fast ship, they would have used the same 14-inch Mark VII rifles as the King George V class without the technical problems that plagued the turrets of that class. Ultimately the Admiralty decided that it could only afford to build just one ship.

Vanguard seen in 1952.

Vanguard, as the new battleship was named, shared many features of King George V and Lion though she had a strikingly different outward appearance. Vanguard shared the same large superstructure as King George V, Lion and rebuilt older heavy warships like Renown. She had a transom stern like Lion with an armor scheme and internal subdivision heavily derived from King George V and Lion but substantially improved.

Vanguard had a unique hull form among British battleships, beamier (wider) than all of them (only slightly moreso than Lion or the older Nelson) but much longer at 248 meters than any except the gigantic Hood. That made for an exceptionably stable seaboat and gunnery platform, even in very heavy weather. Vanguard was much larger than King George V, and only two drydocks in the United Kingdom could service the big ship.

To make her high speed (designed for 30 knots, she actually clocked 29.5, which was faster than King George V but not as speedy as the American Iowa and a good deal less than the German fantasy ships of Plan Z), Vanguard had eight boilers powering four turbines, each driving its own shaft and totaling 130,000 horsepower. In a unique feature, each turbine along with the two boilers that powered it occupied its own room, and could operate independently of the others. That made it almost impossible for Vanguard to be struck dead in the water; damage extensive enough to flood all four rooms would likely be so catastrophic as to sink the ship.

Main armament would be the four dual turrets mentioned above, with eight 15-inch Mark I rifles. A new all-steel Mark II rifle had been developed but not yet tested, and the designers chose to stay with the older, tried-and-true weapon. The gun barrels themselves came out of the stockpile, but the old turrets received such extensive re-working that cost savings must have been minimal at best.

As rebuilt, Vanguard’s turrets had remote power control (a British system that tied the turret’s training and elevation directly to the fire control center) and their guns could be elevated to 30-degree elevation, greatly increasing their range. The turrets themselves received thicker armor on their face plates and had their sighting hoods replaced with new rangefinders which now allowed the guns in the two superfiring turrets to be fired directly forward (similar turrets in all other British ships with 15-inch guns except Hood could not be fired within 30 degrees of the centerline, else the blast effects would enter the lower turret’s hood and devastate the crew within). Shell-handling arrangements were also altered, to place the magazines below the shell-handling rooms as in King George V.

Secondary armament would include eight dual 5.25-inch dual-purpose mounts plus a number of light anti-aircraft guns which increased as construction proceeded. Vanguard was laid down in October 1941 with an estimated completion time of three years, but work moved ahead very slowly as the designers strove to incorporate the benefits of war experience and made constant revisions while other projects took higher priority. A proposal to convert her to an aircraft carrier was firmly rejected by the Director of Naval Construction, who pointed out that it would trade an excellent battleship for a mediocre carrier. She finally launched in November 1944, but was not commissioned until May 1946.

At that point, the war had been over for a year. She underwent sea trials, then returned to the Clyde for conversion to a royal yacht to ferry King George VI and his family to South Africa. Extra accommodations were added, one of her turrets was decommissioned to allow the royal family to take the sun on her after deck, and all of her main gun and most secondary and anti-aircraft ammunition was off-loaded. The king did find her a very pleasant mode of transport.

Vanguard never again functioned as a fully-operable combat ship, making a handful of deployments as a fleet flagship. She rarely fired her main guns, and then only a few shoots with the two forward turrets. A 1955 refit to bring her back to full capability and reduce her seriously overweight condition began but was cancelled before completion, and after serving as a set for the film Sink the Bismarck she went to the breakers in 1960.

An enormously expensive white elephant, Vanguard consumed scarce resources and made no contribution to the defeat of the Axis. Though a potentially effective warship, once the weight problem received corrections, she cost over £11 million to build, with more than £3 million of that going to refurbish her 15-inch guns and turrets. By comparison, King George V cost about £7.5 million.

Vanguard appears in Second World War at Sea: Plan Z, and makes for an effective carrier escort though she is rather lightly armed for her size.

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Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and NASA Journalist in Space finalist, he has a whole passel of books, games and articles on historical subjects. He lives in Birmingham, Alabama with his wife, three children and his dog, Leopold. Leopold likes having a puppy to play with.