The Night Battle That Never Was: Somerville vs. Nagumo, April 1942 (3 Viewers)

[Admiral Beez]

On 5 April 1942, Somerville's Force A, built around HMS Warspite, Formidable and Indomitable, approached to approximately 100 nautical miles of Admiral Nagumo's carrier force at one point. He had roughly 30 Albacore torpedo bombers potentially available for a night strike. I don't know if all, but some of these Albacore's were radar equipped. I believe, British reconnaissance aircraft had located Nagumo's force but did not maintain reliable contact. What do we need to change to make the night attack happen? And what are the most likely and best possible impacts can we expect? Sommerville also needs to do a runner asap, since if the British carriers remained within Japanese striking range after sunrise, Nagumo's surviving carriers will launch a massive counterstrike.

pacificeagles.net/indian-ocean-raid-colombo

In the daylight, there is no comparison.

Could the RAF participate in a night raid at sea? There were still 14 surviving Bristol Blenheims of No. 11 Squadron RAF on Ceylon on 5 April 1942. That might be outside their aircrew training, navigation and expertise. Perhaps in the morning of April 6th a Blenheim strike can hit any damaged carrier left behind. With all of four squadrons (1xBlenheims, 3xHurricanes), plus a few PBYs, it's a shame how little RAF presence there was on Ceylon. Just a few weeks after Nagumo's raid the RAF launched over one thousand bombers over Cologne in Operation Millennium.

 

[Alan Stevens]

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[Alan Stevens]

To make the night attack happen, the key change is not more aircraft but better contact reporting. Somerville's biggest problem was not lack of courage or lack of torpedo bombers; it was that he never had a sufficiently accurate and continuous fix on Nagumo's position. The historical operation was frustrated by poor tactical intelligence, even though the British had warning of Japanese intentions. [wikiwand

If we assume a reconnaissance aircraft maintains contact long enough to provide a good night interception solution, then a strike by roughly 30 Albacores becomes plausible. The British would also need favorable weather and successful navigation, since a night carrier attack against a moving fleet was still an exceptionally difficult operation in 1942.

Even then, I would not expect a British "Taranto in the Indian Ocean." The most likely outcome is one or two torpedo hits on a Japanese carrier or battleship, with perhaps one carrier damaged and temporarily out of action. Sinking a fleet carrier outright would be possible but not the most probable result.

The British advantage was that the Japanese had very limited night-fighter capability and little experience defending a carrier force against a large nocturnal torpedo attack. The Japanese advantage was that Nagumo had five fleet carriers and far more aircraft overall. If three or four carriers were still operational at dawn, Somerville would have to withdraw immediately or risk destruction by daylight carrier strikes.

As for the RAF, I am skeptical that the surviving Ceylon-based Blenheims would materially affect the outcome. A daylight follow-up attack against a crippled carrier might be conceivable, but early-war RAF anti-shipping attacks against maneuvering warships had generally produced poor results. Their value would probably be reconnaissance rather than decisive striking power.

Overall, I'd rate the most likely outcome as:
-- 60%: British attack finds only part of the Japanese force or achieves no hits.
-- 30%: One Japanese carrier or capital ship seriously damaged.
-- 10%: One carrier sunk or crippled badly enough to miss subsequent operations.

The decisive British victory some alternate-history writers envision would require not just contact but an unusually successful torpedo attack and a clean escape before dawn. That's possible, but it is several favorable assumptions stacked together.

Historically, Somerville's plan was actually one of the more promising Allied carrier concepts of early 1942. Had the British achieved reliable night contact, Nagumo might have received the first nasty surprise of the Pacific carrier war months before Midway. The problem is that finding the enemy at sea was often harder than hitting him once found.

 

[yulzari]

Somerville had only a small window of time between Nagumo being located reliably and having withdrawn himself far enough away to avoid retaliation. In that time he has to make the decision, launch his torpedo bombers, leave them to cruise to the target, carry out the attack and return and land in time for him to withdraw out of probable risk of retaliation. The only way to maximise it long enough to do all of this is having regular reliable knowledge of Nagumo's position, speed and direction. All of this at night. Maintaining a shadow in daylight will invite Nagumo's fighters to reach and engage with the shadowing aeroplane. Presumably a Fairey Fulmar from his meagre stock of fighters on his carriers. Just possibly along with some of the 44 Fulmars operating from Ceylon to assist in maintaining the shadowing aeroplane but the range for them leaves little time to loiter. It could all come together but it would be a matter of chance. If it came to using the Swordfish of HMS Hermes as well as the Albacores of the other carriers then the window becomes vanishingly small.

As I see it Nagumo's purpose was to assess the freedom to operate in the Indian Ocean in making the raid on Ceylon. It may be been enough for him to learn that his fleet was located by a Royal Navy fleet at night in mid ocean for a potential night attack and cause him to withdraw having found the answer to his question. Especially as his fleet was removed to the Pacific afterwards where it was needed.

 

[Admiral Beez]

Overall, I'd rate the most likely outcome as:
-- 30%: One Japanese carrier or capital ship seriously damaged.

If this occurs the night of April 5 1942, (hopefully Sommerville's carriers are not destroyed in the morning), unless Japan can pull a Yorktown-type rush repair, Nagumo will be down a carrier for Coral Sea less than a month away, starting May 4. And I'm not convinced that Japan can fix a damaged carrier quickly, for example Shōkaku (hit by three USN bombs May 8, 1942) needed 67 days in dock before returning to service in mid-July. IJN carriers seem to withstand torpedo hits better than bombs, with five ships (Jun'yō, Hiyō, Ryūhō, Taiyō, and Un'yō) withstanding torpedo hits and returning to service; so Sommerville's Albacores might wish that they'd brought bombs instead.

At Coral Sea, Japan committed two fleet carriers, Shōkaku and Zuikaku, plus the light carrier, Shōhō. The other four fleet carriers, Akagi, Kaga, Sōryū and Hiryū plus the light carrier Zuihō were in Japanese home waters refitting, replenishing and preparing for Midway, while Ryūjō was still returning from operations in the Indian Ocean and East Indies; Jun'yō had only just commissioned; and the obsolete Hōshō was assigned to secondary duties. Unless another carrier is pulled from the refit, the IJN will enter Coral Sea with only two ships, which may see USS Lexington survive the battle and serve at Midway.

Mention of Ryūjō above has me thinking, after damaging one of Nagumo's carriers above, could Sommerville have then attacked this small carrier operating alone in the Bay of Begal?