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Royal Navy Battlecruisers in WWII:
The Sad History of Modernization

By Kristin Ann High
March 2015

Battlecruisers were highly prized and jealously guarded by the admirals who commanded them and inspired ferocious loyalty in their crews. By the end of the 1920s it was clear that the old enmities were very much alive in Europe and Asia, and the battlecruisers of the world's navies would not leave the scene any time soon.

The German Reichsmarine was building Panzershiffe, fast, heavily-armed but lightly-armoured ships that could outrun any American, British or French battleship and outgun any of those nations’ cruisers. Panzershiffe were not so much traditional battlecruisers as a modern take on the armoured cruiser of the Great War, adapted to employ modern technologies — marine diesels, superb DCT and observation seaplanes, and underway replenishment — to deal with their nemesis, the battlecruiser.


Renown, furthest modernized and longest lived.

As Germany was unlikely to find herself involved in the Pacific (at least as far as the officers of the Reichsmarine were concerned), the role of nemesis belonged to just three ships: Renown, Repulse, and the terrible Hood. The British understood this as well, but they had built all their "legal" battleship tonnage with Nelson and Rodney and could not afford to build more. Initial British "updates" to their ships had proven inadequate, and from the end of the 1920s to the outbreak of war in September 1939 the Royal Navy did what it could to modernize its battleline, and its battlecruisers.

HMS Refit and HMS Repair

The plan was to modernize the oldest ships first. As a result, the British never got around to reconstructing Hood, as so much time was spent refitting, reconstructing, and re-reconstructing Renown, followed by a not quite so extensive effort on Repulse; war intervened before her re-reconstruction could be completed. It was this near-continuous process of modernization that led to the two Renown-class battlecruisers being nicknamed “Refit” and “Repair” in the fleet.

For all of that, many at the admiralty believed that Hood remained superior to the older Renown and Repulse, even though she received only the most basic modernization refits. Hood received a "modern" anti-air fit about on par with the woeful standard of the time (American, British, or French, at least), and by the outbreak of war she had capital ship-class RDF and wireless telegraphy, but she did not have her armour deck relaid or thickened, nor were her vitals re-armoured. Indeed, there was strong opinion that, her shell handling having been improved after Jutland, she was as protected against plunging fire as a battlecruiser could afford to be.

The reasoning was primarily based on the first full reconstruction of Repulse, which included significant improvement of her armour deck. After this reconstruction, Repulse was proof against plunging fire to her magazines or machinery spaces from even the German 15"/52-Calibre Schiffskanone Construktionsjahr 1934 (the accepted English abbreviations are 'SK' and 'C/xx'; the rifle is thus the 15"/52-Calibre SK C/34), firing the standard 1,764-pound APC, and that only at ranges of 30,000 yards or more. The additional weight in armour was balanced in the accepted fashion by enlarging her anti-torpedo bulges, but none of this was accompanied by any improvements to her machinery. Her flank speed fell to 28 knots.
Moreover, Repulse's chances against flat-trajectory fire if faced with, say, Bismarck do not look promising, at least on paper. Her main belt, after reconstruction, was only 91⁄2"; 4" in front of her magazines and machinery spaces, up from her as-built 61⁄2" main belt.

Bismarck's 15"/52-calibre SK C/34 APC shells could theoretically penetrate Repulse's main belt at all ranges, but the characteristics of German APC shells (Panzersprenggranate mit Kopfzünder und mit Haube, 'Pzgr. m.Kz u. m.Hb') were such that the shell had better post-penetration characteristics at low obliquities (see Nathan Okun's superb information) . Bismarck could achieve a definitively favourable impact obliquity of 16° at 20,000 yards, giving her a calculated penetration of 161⁄2" of Repulse's British armour plate, far in excess of what Repulse could take. So, no matter how far one stretches allowances for angle-off (obtuse or acute angles of fire relative to the target), the worst tactic for Repulse was the one generally suggested as best for Hood — to close as rapidly as possible on Bismarck. And at 28 knots, Repulse could not outrun Bismarck either, so she really didn’t have any good options against such an opponent.

As for Hood, she was already much larger than her younger sisters, and could ill afford to surrender her all-important two-to-three-knot speed advantage over Panzershiffe to armour protection she was unlikely to need in her stated mission of hunting commerce raiders, and which would be of little or no avail against battleships. As built, she was proof against the German 11"/52-calibre SK C/28 at any range, and against the improved 11"/55-calibre SK C/34 out to 30,000 yards, a range at which no hit was ever scored by surface gunfire in WWII, to my knowledge).

As the 11"/55-Calibre SK C/34 armed the "improved" Panzerschiffe designs 'D' and 'E', the light battleships Scharnhorst and Gneisenau (aka “Salmon” and “Gluckstein” to the ratings of the RN), it was hard to argue that extra armour without increased propulsion was going to make Hood more effective, rather than less.

The Loss of HMS Hood

Sadly, the first of these three sisters to die was the one the Admiralty felt was best prepared to face the enemy. Conventional wisdom makes no mystery of Hood’s fate — she was struck by a 15" APC shell from Bismarck that plunged through her inadequate armour deck and detonated her 4" magazine, which then blew up her main magazine; Jutland all over again. Some alternatives proposed have been an underwater penetration by one of Bismarck's 15" shells, or sloppy magazine safety on the part of Hood's crew — a practice left over from her Mediterranean service.

There is, however, another, rather more technical appraisal of Hood's fate. In Sea Battles In Close-Up: World War II by Martin Stephen, the then-director of naval construction (DNC), Admiral Goodall, believed that the cause of the explosion was not the result of the 4" magazine detonating. Firstly, the origin of the explosion was at the base of the mainmast, 65 teet away from the nearest magazine of any kind. Secondly, the first hit Hood took was an 8" HE/SAP round ("Sprenggranate mit Bodenzünder und Kopfzünder," a high-explosive shell having both base and nose fuses) from Prinz Eugen, which caused a large fire amidships aft.


Hood in happier times.

The DNC felt that this fire, which certainly caused significant damage on the weather decks — the huge fires were visible to all the combatants, and assisted Bismarck's fire control officers — apparently caused "serious damage" below as well. The area struck by the 8" HE round was directly above the officer's quarters, all of which were still furnished with the highly flammable wooden and fabric furnishings of the peacetime navy. This is also the part of the ship where the torpedo warheads were stored for Hood's deck-mounted torpedoes; 4,000 lbs. of Torpex protected by 3" box protection, woefully inadequate for engaging the ships which were Hood's naturally quarry, much less a full-fledged battleship. According to Grove and Stephens, if one or more of the eight shells of Bismarck's fourth salvo landed in this area, and either directly struck the torpedo warhead magazine or struck close enough to cause the warheads to "go up in sympathy," the result:

. . . would have been an explosion where it was actually observed. Such an explosion could break the ship's back, already weakened in this area by the previous damage", according to Goodall. No one likes to admit making a mistake, and a bureaucracy is almost institutionally incapable of doing so. The DNC at the time of Hood's building was Admiral D'Eyncourt, and he fought tirelessly to have the torpedo fittings removed; he was ultimately successful, sort of. The fitting were retained aboard, but not as "war fittings" — they were "strictly" for training purposes, to be removed prior to Hood's sailing in war condition.

Unfortunately, when Hood was given her "modernization refit" in 1929-1931, the plan to reconstruct her armour deck was not undertaken, as noted above. This allowed the Admiralty to re-instutute the torpedoes as "war fittings" by providing them with the aforementioned 3" box protection. Thus, the Admiralty's stubborn insistence on a weapon generally accepted as worthless and dangerous in a capital ship—the above-deck torpedo—may have led directly to Hood's destruction.

As always, the various bureaucracies of the institution — in this case the Admiralty — sought to blame humans, not the system. Hood's poor magazine discipline and the practice of having large amounts of 4" ammunition in ready boxes was responsible for Hood's loss, not bureaucratic jealousy and personal politics among the Sea Lords (there are three, just for the record, with a fourth being the political appointee First Lord of the Admiralty).

The Loss of HMS Repulse

The second, and last of the British battlecruisers to be sunk, was Repulse, and again there is no mystery surrounding her fate. On 10th December 1941 she was struck by 86 land-based, twin-engine naval attack bombers: 60 Mitsubishi G3M2 NELL's (Navy Type 96 Model 21/Model 22 Attack Bomber) carrying torpedoes and bombs, and 26 G4M1 BETTYs (Navy Type 1 Model 11 Attack Bomber) carrying torpedoes. She took at least five torpedoes and one bomb. Japanese naval aircrews were the best-trained aircrews in the world in 1941, naval or otherwise. Their horizontal bombing was largely ineffective, but one hit did strike Repulse on her hangar. The bomb struck through to her armour deck, but did not penetrate, though the gout of flame and the billowing smoke gave alarm to Force 'Z' and elation to the Japanese pilots.

Likewise, the first torpedo hit struck her bulges, and failed to defeat her underwater protection — no mean feat considering the power of the Japanese Type 91 Model 1 torpedo (it had a 331-pound warhead of Type 97 explosive, this being better than TNT but less potent than Torpex). The last attack on Repulse was launched by either the remaining BETTYs or another group of NELLs; most likely it was the last wave of BETTYs, and thus comprised eight aircraft rather than nine. Unfortunately, Repulse had closed on the flagship, the luckless and lll-fated Prince of Wales, to render assistance — probably not the wisest course in the midst of attack when there were destroyers at hand.


Repulse, lucky to the end.

The Japanese planes caught Repulse in a classic anvil attack, and four of the eight torpedoes struck her, three to port and one to starboard (this being the second torpedo hit to starboard). These sorts of hits were too much for any ship, and Repulse's anti-torpedo protection was well and truly defeated. She listed to port and the order to abandon ship was passed. According to Capt. Tennant, her OC, the men abandoned ship under the command of the executive officer and went over the side in good order and with no sign of panic or "ill-discipline". A Naval officer true to the traditions of Royal Navy and United States Navy, Tennant remained on the bridge as his ship went down. He grasped the wheel to keep from sliding over when she rolled, but Repulse was a lucky ship, and a kind one, even in death: she threw her captain clear as she went down by the stern, and her men kept the stunned and shaken Tennant above water until destroyers could pull them from the sea.

Prince of Wales, on the other hand, was as vindictive as she was unlucky, for screams could be heard through the ventilators as she rolled over to her death, and neither Capt. Leach nor Admiral Philips survived her. There is no truth, however, to the story that Prince of Wales' bad luck was due to the break in tradition whereby Prince of Wales was referred to in the masculine (he, him, his); no sailor would have so affronted the dignity of a ship by using the masculine to address her, whatever she was named!

HMS Renown

Renown, the most modernized and most heavily reconstructed battlecruiser, fought her way through the Mediterranean and the Atlantic, and hunted what few German surface ships she could reach. She survived the war and was sold to the breakers on 19th March 1948. She was the most successful of the three British battlecruisers, and the Germans certainly feared her.

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