Big Guns Sink Ships! by Mike Creasy
Or do they?? What did it take to sink a battleship or battlecruiser in a ship-to-ship gun battle? The answer is somewhere between "not much" and "a long pounding". One trouble is, there weren't many ship-to-ship gun battles in the dreadnought age and the actual hit count often a bit fuzzy. That's because the loser often sank and the victor liked to claim their highly accurate gunnery was the cause..... too often, the sinking was caused by bad habits (leaving magazine flash doors open), air dropped bombs or - the scourge of capital ships - torpedoes!!!
Let's look at some of the major ship battles in the 20th century between heavily armored ships with heavy guns (over 11"). The candidates are:
Tsushima Strait - in 1905;
Dogger Bank - in 1915;
Jutland - in 1916;
Denmark Strait - in 1941;
Savo - in 1943;
There were many other big ship encounters, but the effect of air dropped bombs and torpedoes was such that we can't really gain much insight into naval gunnery. So, lets start with the Russo-Japanese War battle of Tsushima.
Over 20 capital ships in each fleet, mostly pre-dreadnought armored ships and early dreadnoughts, mostly 12" guns and top speeds of about 23 knots. The battle lasted two days - each side "retired " for the night - and each side fired many, many shells. Hits were another thing. Japanese gunnery and battle tactics under Admiral Togo were far superior to Admiral Rozhestvensky's poorly trained fleet, but it still took over 45 minutes for the battleship Knyaz Suvorov to be crippled. The Japanese fleet eventually sank or disabled most of the Russian fleet, while Japan lost 3 destroyers. The answer to our question here is: Lots!
The WW1 battle of the Dogger Bank was a little more precise, with 5 new British battlecruisers taking on 4 German battlecruisers. HMS Lion (13.5") opened fire on SMS Blucher (8.2") at 20,000 yards and obtained hits after about 10 salvoes. Blucher managed one hit on Lion, but the shell did not penetrate her armor plate. Blucher took about 30 hits and capsized after an hour. Other heavy units exchanged ineffective fire for nearly an hour, until SMS Seydlitz (11.2") took a 13.5" hit on her after turret. The shell penetrated her armor and started a fire in ready propellant charges. The after magazines were flooded before the fire could spread, but the ship was out of action. Soon after, Lion took several hits from SMS Derfflinger (12") one of which penetrated her armor a forward turret, causing a propellant fire. Another of these hits was to the port engine room, causing the stoppage of that engine.
The nine capital ships in this action fired upwards of 400 shells each, obtaining about a dozen hits. Mind you, those hits caused lots of damage, so the answer here is: 12 or less!
The battle of Jutland a year later involved much bigger fleets, over 20 big ships on both sides. Again, many shells were fired and the ratio of shots to hits was very small. The important thing, especially for the British, was the realization that the battlecruiser concept - reduced armor in exchange for speed - was not viable for two reasons. First, because the new turbine power plants could push big, heavy ships at destroyer-like speeds. Second, because long range gunnery meant that incoming shells could go over the top of massive side-armor belts; heavier deck armor was now required.
Large naval gunnery is a complex science, and there is no way to cover all the parameters. Each capital ship would have an assessment of their own vulnerability in terms of the range at which an enemy shell could penetrate their armor, and at what points. They would also have an evaluation of each enemy ship, in terms of its vulnerability to shellfire. All these assessments would be based on range, because that determines the angle of fall for the incoming shell as well as the striking velocity. The greater the range, the higher the angle of fall and the lower the striking velocity. Consider this British Admiralty assessment of the last battlecruiser built - HMS Hood. They knew when she was built in 1916/19 that an incoming 15" AP shell fired from over 19,500 yards could penetrate to a magazine.
When HMS Hood and KMS Bismarck met in 1941, Admiral Holland was well aware of this design flaw and planned a head-on intercept to close the range at the highest possible speed. His plan didn't work out, and Hood and Prince of Wales ended up approaching from the beam - the worst possible angle for Hood. At 25,000 yards all 3 ships began firing. Bismarck's third salvo set off a large fire on Hood's upper deck, probably some ready-use ammunition for the small guns. As the British ships closed the range to 19,000 yards, Admiral Holland ordered a turn to port to bring the X and Y turrets to bear, but it was too late. Hood took a perfect hit from Bismarck and a magazine exploded. Prince of Wales took four hits from Bismarck and some 8" hits from KMS Prinz Eugen. Her bridge was destroyed and she broke off the action.
Our answer here unfortunately, is: one. Bismarck was brought to bay 3 days later by several heavy units. Disabled by an air-dropped torpedo, she took massive hits from HMS Rodney (16") and HMS King george v (14") at ranges from 16,000 down to 4,000. Rodney alone fired 380 16 inch bricks, each weighing 2,048 lbs. Reduced to a smoldering hulk, Bismarck stayed afloat until the coup de grace either from torpedoes or from scuttling charges, or both.
The answer: lots and lots and lots. A night action in Ironbottom Sound near Savo Island in 1942 marked the first time radar range-finding was used. The American battleships USS Washington (16") and USS South Dakota (16") met up with the old Japanese battleship IJN Kirishima (14") while it was escorting a supply convoy to Guadalcanal. South Dakota takes a single 14 inch hit, plus numerous smaller calibre hits from escorting vessels. None penetrate her armor. Washington uses radar to approach Kirishima undetected to a range of 6,000 yards. She lands at least nine 16" shells (out of 75 fired) and sinks Kirishima.
The answer here: nine. So the final answer to our question is: your call. Battleships and battlecruisers were magnificent machines for peacetime navies, well-suited to providing artillery support for land operations, but far too vulnerable to bombs and torpedoes to warrant their cost. Designed to fight the last war, these monsters were the naval version of the Maginot Line! Makes you wonder what the next version the battleship will be!
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Bibliography
Naval Battles of the First World War, Geoffrey Bennett, Pan Books,1974
The War at Sea Volume 1, Capt. S.W. Roskill, HM Staionery Office, 1954
Naval Battles of the 20th Century, Richard Hough, Constable & Co, 1999
Naval Weapons of WW2, John Campbell, Conway Maritime Press, 1985