Somerville against the Rising Sun...

[dunmunro]

On April 05 1942, the RN FAA had a stunning victory within its grasp:

Somerville's Force A, with the carriers Indomitable and Formidable had located the Kido Butai at 1600 and by 1726 had closed to within 130 miles. Unfortunately the first Albacore to sight the KB, at 1537 was shot down and the 2nd at 1600 only got off a partial position before the radio operator was wounded. Somerville had strikes ranged on both his carriers for night TB strike but hesitated to launch a strike without better information of the KB's position. After the first position report at 1600, Somerville's airgroup commander RA Boyd neglected to launch another search aircraft. Somerville also had Hermes which was providing A/S cover for his Force B.

A false report received just before sunset at 1800, caused Somerville to search in the wrong direction for the KB with his ASV radar equipped Albacores and by morning the FAA's golden opportunity had vanished forever.
FAA assets
Force A:
Indomitable:
Warspite (2-4 Walrus) + several aircraft equipped cruisers
9 Sea Hurricanes
12 Fulmar IIs
24 Albacores (some with ASV)
Formidable:
18 Martlets
21 Albacores
1 Swordfish (ASV)
Force B:
4 R class BBs and several cruisers
Hermes:
12 Swordfish
Ceylon:
Aprox 30 Fulmars
RAF Ceylon
~40 Hurricanes
~12 Blenhiems
~12 PBYs

Kido Butai:
5 carriers and about 275 aircraft:
AKAGI: 53-55 (18 or 19 A6M, 17 or 18 D3A, 18 B5N)
SORYU: 54-55 (18 or 19 A6M, 18 D3A, 18 B5N)
HIRYU: 52 or 54 (16 or 18 A6M, 18 D3A, 18 B5N)
SHOKAKU: 56 (18 A6M, 19 D3A, 19 B5N)
ZUIKAKU: 55 (18 A6M, 19 D3A, 18 B5N)
4 BCs and several cruisers.

Your mission, is to use the FAA's available assets and destroy the Kido Butai. I would argue that the FAA opportunity was lost because the Fulmar was not used for recon, and probably was not adequately appreciated for it's potential as a strike aircraft since the RN had not faced CVs prior to this date. I would argue that if the FAA CVs had used their available assets more aggressively and prepared an immediate DB attack, that the KB could have been largely destroyed on April 05 1942. The Hermes was overdue for a refit to increase her avgas capacity and allow her to carry Fulmars, and this is why she was at Ceylon on April 09. If Hermes has received this refit sooner, she might have been able to provide a valuable role in providing Somerville with recon and strike capability. For the purposes of this hypothetical scenario we might imagine that Hermes has 12 Fulmars on board and is included in Force A.

[Bgile]

Wiki gives Fulmar's bomb load as 2x250 lb bombs. I take it that isn't correct and that it could carry 500 lb bombs. How did that effect it's performance?

Did Fulmar pilots practice dive bombing routinely? Obviously SBD pilots did because that was their chief function, but for the Fulmar it was as a fighter.

[dunmunro]

Wiki gives Fulmar's bomb load as 2x250 lb bombs. I take it that isn't correct and that it could carry 500 lb bombs. How did that effect it's performance?

Did Fulmar pilots practice dive bombing routinely? Obviously SBD pilots did because that was their chief function, but for the Fulmar it was as a fighter.

The Fulmar II could carry either a 60 igal DT or a 500lb bomb on a centreline hardpoint. The DT was trialled in Oct 1941 and weighed 550lb when full. Apparently the mods required for the DT also allowed carriage of the 500lb centreline bomb. I have undated pictures of Fulmars doing practice drops of a 500lb bomb, but info on the use of the aircraft as a DB is not very extensive however all my references state that up to 500lbs of bombs could be carried on the MkII. I would suspect that carrying either 2 x 250lb or 1 x 500lb would reduce the climb rate somewhat but would not cause much reduction in max speed. An interesting spec is that the Fulmar carried 8 x .303mgs versus 4 on the Skua. A quick check shows that one MG and 1000 rnds weighs about 50kg , so removing 4 guns and reducing the ammo load on the remaining two to 500 RPG would reduce weight by 225 kg or about 500lbs. This configuration would allow for a centreline DT and 2 x 250lb bombs with no increase in TO weight. The Fulmar had a search radius of 280nm miles at 155 knts at 10k ft with a DT, so a 2 x 250lb Fulmar would have a strike radius of something like 250nm, if 4 guns were removed. Removing 6 guns would appreciably improve its strike performance. Apparently the B.E. Fleet began to practice using the Fulmar with a 500lb bomb after April 1942, probably in response to the need for a high speed strike aircraft against IJN CVs.

[Bgile]

Why would a Fulmar carry a centerline 500 lb bomb if it didn't have the equipment to dive bomb with a centerline bomb?

Did people actually remove machineguns from fighters in order to increase range or payload? I think this is the first I've heard of that.

[dunmunro]

Why would a Fulmar carry a centerline 500 lb bomb if it didn't have the equipment to dive bomb with a centerline bomb?

Did people actually remove machineguns from fighters in order to increase range or payload? I think this is the first I've heard of that.

The Barracuda dropped 1600lb AP bombs on Tirpitz using an identical centreline configuration. A 500lb SAP was probably considered more effective than a pair of 250lb bombs, against a carrier.

Removing 2 x .5" guns was a common field mod on the F4F-4, and removing 2 x 20mm guns from a 4 cannon Hurricane was also a common field mod. The P51 was also modded and field modded by reducing the armament. Removing some armament from fighters was actually pretty common. Swordfish often left the air gunner behind if the aircraft had to be lightened for improved STOL or to increase range via an extra fuselage tank.

[RF]

On April 05 1942, the RN FAA had a stunning victory within its grasp:

In reality this is information derived after the event. Given the defensive mode of the RN at the time I cannot see the ''famous victory'' coming off, more likely the Japs would win but at some cost.

[José M. Rico]

Dunmunro, this is an interesting scenario but I'm not sure of its intent since you seem to have already decided the British would win.

[dunmunro]

Dunmunro, this is an interesting scenario but I'm not sure of its intent since you seem to have already decided the British would win.

Like all hypothetical scenarios, it is a chance to explore a what if situation. It is apparent that the RN could "win" in the sense that they had time to launch a strike, just at sunset against an enemy CV task group that did not know where the RN CVs were, and then withdraw undercover of darkness to avoid any possibility of being detected. The intent is too explore the changes needed to the FAA to maximize the probability of success.

[19kilo]

Given the state of training the Japanese had at that time I would think the RN would have been slaughtered. Churchill said as much.

[RF]

Dunmunro, this is an interesting scenario but I'm not sure of its intent since you seem to have already decided the British would win.

I don't see this as the likely outcome, as I say this ''intent'' is based on hindsight and involves risks Somerville most certainly would not have taken.

[dunmunro]

I don't see this as the likely outcome, as I say this ''intent'' is based on hindsight and involves risks Somerville most certainly would not have taken.

Somerville had a strike prepared on the afternoon and evening of April 05 and was waiting for confirmation of the KB position so that he could launch a night TB attack with his Albacores. This is part of the historical record.

[Keith Enge]

The historical record is that Somerville sensibly hid at the Addu Atoll and then retreated to the African coast. He, unlike you, had an appreciation of the limits of the hardware that he had. The relative capabilities and range differential were too great; his force would have been slaughtered with damage to the Japanese limited to a loss of not much more than a handful of planes. Just the existence of the secret base at Addu Atoll was an acknowledgement of the RN's weakness in the Indian Ocean.

[dunmunro]

The historical record is that Somerville sensibly hid at the Addu Atoll and then retreated to the African coast. He, unlike you, had an appreciation of the limits of the hardware that he had. The relative capabilities and range differential were too great; his force would have been slaughtered with damage to the Japanese limited to a loss of not much more than a handful of planes. Just the existence of the secret base at Addu Atoll was an acknowledgement of the RN's weakness in the Indian Ocean.

Somerville attempted to find and strike the KB on April 5/6 and had a strike ranged on his carriers waiting for location information regarding the KB. After April 06 he realized that he was up against 5 carriers and was saddled for 4 older 20 knot BBs that were rapidly running out of fuel and water and no choice but to keep his distance:

40. If he held on this course he would be at 0400 in a position to deliver a night air attack on Addu Atoll. This seemed quite a possible course of action. In any case it was necessary for Force A to keep clear to the southward and for Force B (estimated to be 135 miles astern in position 0-12N, 75-15E at 1700) to steer southward so that Forces A and B could close for supporting action at daylight the following morning (6th April). It as also necessary for Force B to steer to southward to keep clear of the enemy carrier force should it be proceeding to attack Addu.

41. At 1726, therefore Force A altered course to 210 degrees at 18 knots and a signal was made to Vice Admiral, 2nd in Command and to DORSETSHIRE to steer south, though by this time I entertained grave fears concerning the fate of the two 8” cruisers. As I had received no signal from them that they were being attacked I felt it was possible they had escaped and were maintaining W/T silence.

42. At 1800 I received a signal from Rear Admiral, Aircraft Carriers, stating that reconnaissance aircraft reported the estimated enemy’s position 20 degrees 120 miles at 1710. This position was very close to the previously reported 1600 signal. The enemy’s course had not been given in either of these reports, but the positions fitted in well with the course received in paragraph 38.

43. At 1817 a further signal was received from Rear Admiral, Aircraft Carriers, adjusting the 1600 position of the enemy force, amplifying it to include 2 carriers and 3 unknown vessels and giving the course as northwest. This was the first indication I had of an enemy course to the northwest.

44. I immediately ordered Force A to alter course to 315 degrees and instructed Vice Admiral, 2nd in Command to conform. These movements had the object of keeping Force A within night air striking distance of the enemy force, trusting to an A.S.V. search to locate the enemy, and to being Force B within supporting distance should it be necessary to retire in that direction. A dawn rendezvous was arranged with Force B in approximate position 3N, 75E.

45. As no news had been received of DORSETSHIRE and CORNWALL, the presumption was that they had been sunk.

46. At 1930 a night search with A.S.V. aircraft commenced to cover the section 345 degrees to 030 degrees to a depth of 180 miles. Nothing was located by this search.

Monday 6th April

47. From 2100 to 0600 further A.S.V. searches were carried out to cover the section 20 degrees to 80 degrees to a depth of 200 miles. These searches also failed to make any contact with the enemy but reported that Force B was 220 degrees 25 miles away from Force A at 0400.

48. At 0615 Force A altered course to 135 degrees and sighted Force B ten minutes later. By 0720 the fleet was formed up and course altered to 90 degrees.

49. Whilst no further information had been received regarding the enemy’s movements nothing occurred to diminish the possibility of the enemy’s being in the vicinity of Addu Atoll, either to attack it by air this morning or to await the return of the Eastern Fleet.

50. I intended to keep clear of the superior enemy forces by day; to try to get in a position to attack them by night air striking force on their possible return from the Addu area, and also to rescue the survivors from DORSETSHIRE and CORNWALL. I therefore steered east and at 1115 course was altered to southward in the direction of the wreckage reported the previous evening.

51. At 1300, ENTERPRISE with PALADIN and PANTHER were detached to search for survivors in the vicinity of the wreckage position. Air search was provided to assist; further fighter escort was sent to cover the operation. These ships were successful in picking up a total of 1122 survivors and rejoined the fleet at noon the following day in Veimandu Channel. At 1800, when about 50 miles from the wreckage position course was reversed and the fleet retired to the northwest. All round air searches were carried out to a depth of 200 miles; nothing was seen.

52. At about 1400 a signal was received from CinC Ceylon estimating that a strong Japanese fleet was still somewhere between Addu Atoll and Colombo. I therefore decided to keep clear of Addu area, at any rate until after daylight on the 7th

http://www.naval-history.net/xDKWD-EF19 ... uction.htm

[Keith Enge]

There are two telling phrases in the report you cited. The first is "I intended to keep clear of the superior enemy forces by day; to try to get in a position to attack them by night". The second is later in the same report, "57. At 0700 aircraft were flown off from the carriers to carry out an all round search to a depth of 175 miles." This just shows the differences in capabilities of the two forces. The British search range was 175 miles; Japanese attacks often occurred at twice that range. The British, with their few carrier planes, couldn't do enough damage to the Japanese during to night to escape a return attack the next morning which would have annihilated the British fleet. The British had to be so close to attack that they wouldn't have enough time left after recovering their planes to get far enough away during the remaining night hours to escape the Japanese revenge in the morning. Nothing in Somerville's report indicates that he expected to win a major victory; as he said, there were "superior enemy forces". He hoped for a hit-and-run nuisance raid but given the disparity in attack ranges, that was impossibly dangerous.

[dunmunro]

There are two telling phrases in the report you cited. The first is "I intended to keep clear of the superior enemy forces by day; to try to get in a position to attack them by night". The second is later in the same report, "57. At 0700 aircraft were flown off from the carriers to carry out an all round search to a depth of 175 miles." This just shows the differences in capabilities of the two forces. The British search range was 175 miles; Japanese attacks often occurred at twice that range. The British, with their few carrier planes, couldn't do enough damage to the Japanese during to night to escape a return attack the next morning which would have annihilated the British fleet. The British had to be so close to attack that they wouldn't have enough time left after recovering their planes to get far enough away during the remaining night hours to escape the Japanese revenge in the morning. Nothing in Somerville's report indicates that he expected to win a major victory; as he said, there were "superior enemy forces". He hoped for a hit-and-run nuisance raid but given the disparity in attack ranges, that was impossibly dangerous.

The fact that two RN CVs were outgunned by five IJN CVs is hardly a surprise, or that Somerville wouldn't consider that he was the underdog . Given his limited aircraft complement Somerville had to balance the number of search aircraft and thus search distance versus keeping enough aircraft on hand to launch an efficient strike. Oddly, given their vastly superior numbers and supposed superior range, the IJN search aircraft never did find Somerville's main body. If Somerville had struck the IJN at night, he would have had many hours to withdraw out of range, especially since there is a high probability that one or more IJN CVs would be crippled, especially in the early evening hours of April 05.