Rn vs IJN

[Admiral Beez]

It's not that slim a record. It's an impressive list of warships attacked and even sunk, It's a better record if you compare it with the RAF and FAA record, surely?

Indeed. I don't think British aerial torpedoes ever sank anything larger than a destroyer at sea. Yes, they scored important torpedo hits, such as those on the battleships Bismarck and Vittorio Veneto, cruisers Lützow, Pola and Trento (later scuttled), but the British had nothing like the success against heavy warships the Japanese managed with aerial dropped torpedoes. Had it not been neglected, RAF Coastal Command might have been the dominant aerial torpedo arm in 1939-40.

 

[RCAFson]

Indeed. I don't think British aerial torpedoes ever sank anything larger than a destroyer at sea. Yes, they scored important torpedo hits, such as those on the battleships Bismarck and Vittorio Veneto, cruisers Lützow, Pola and Trento (later scuttled), but the British had nothing like the success against heavy warships the Japanese managed with aerial dropped torpedoes. Had it not been neglected, RAF Coastal Command might have been the dominant aerial torpedo arm in 1939-40.

The FAA sank a lot of merchant ships but we have to remember that the IJN's KB was free to expand during the two and 1/3 years when the IJN was not engaged in a hot war, while the RN and FAA definitely was, and as a consequence could never mass their carriers for large scale strikes. Of course the RMI and KM made themselves scarce when they knew that RN carriers were at sea and both Axis navies often had the benefit of shore based aircover.

 

[cherry blossom]

Snip.... The follow up Second Naval Battle was a case of being overwhelmed by a far superior American force, but it still interesting to note that the one time the Type 93 torpedo had the chance to accomplish the mission it was designed for it failed to score a single hit on the American battleships....snip

This may need a small caveat. If you look at the Japanese destroyers that launched torpedoes during Second Guadalcanal, most were old and not fitted with the Type 93. Some of the others had fought at First Guadalcanal and may have used their torpedoes. The two sent by Tanaka arrived as Lee turned away, which may account for them missing. That still doesn't excuse Atago* and Takao for missing with their Type 93s but to some extent Lee was facing the second team.

* Atago's crew might argue that having a very senior admiral on board was an excuse but Kondo had previously performed very well in command of a desk, for example, arguing against attacking America or arguing that Operation C was a distraction.

 

[Admiral Beez]

When you look at the RN (of 1941-42) and IJN it seems like combining the two would make for an awesome fighting machine.

British: air intercept and gunnery radar, FDO, fighter coordination and radio communications, convoy and ASW expertise, damage control and AA
Japanese: Torpedoes and torpedo doctrine, both from surface ships and aircraft, naval aviation, land-based torpedo bombers, long range ops expertise, larger carriers

Imagine Yamato chasing Bismarck in the Denmark Srt. And the USN's submarines might not have a field day with Japanese shipping if its covered by British-level ASW and convoy techniques.

 

[WARSPITER]

As far as larger enemy surface vessels go, the Mediterranean and Atlantic weren't really heavily populated with targets.

 

[EwenS]

When the enemy prefers to stay tucked up in port behind his AA defences, you either have to attack him there (Taranto, Brest & Dakar) or wait till he decides to come out.

And when the larger Axis warships did come out to play in the Atlantic & Med on those few occasions, there was the general shortage of carriers in the right place at the right time (none in the Med East of Malta from May 1941 to July 1943 for example) and only a handful (4 IIRC) of FAA shore based Swordfish / Albacore squadrons on Malta and in Egypt (with those on Malta suffering heavy losses in Lutwaffe bombings).

The RAF was also short of modern torpedo bombers throughout the 1939-42 period. The Beaufort only entered service in Nov 1939, becoming operational about April 1940. The first of these were not sent to the Med until late 1941. Such was the shortage of those aircraft Wellingtons & Hampdens had to be converted to fill the gap in 1942.

But still the following major Axis ship torpedoings by British aircraft come immediately to mind:-

Battleships:-
Bismarck (obviously!)
Gneisenau (at Brest 6 April 1941 by an RAF Beaufort. The pilot won a VC for that attack but sadly lost his life doing so)

Conte di Cavour (sunk at Taranto)
Duilo (Taranto)
Littorio (torpedoed twice - Taranto by the FAA and at sea in June 1942 by an RAF Wellington during Operation Vigorous)
Vittorio Veneto (at Matapan)

Richelieu ( French, at Dakar July 1940 by a Swordfish from Hermes)

Cruisers:-
Lutzow (June 1941 off Norway)

Trento (during Operation Vigorous - later sunk by a sub)
Pola (Matapan - later sunk by battleships)

Destroyers:-
There were 4 Italian destroyers torpedoed in ports in 1940 by the FAA.

These are the successful torpedo missions. Others were flown against major Axis warships that proved unsuccessful. Channel Dash in Feb 1942, strike on Prinz Eugen in Norwegian waters in May 1942 come to mind.

 

[EwenS]

RAF Beaufort TB squadrons 1939-42:-

22 - received Beauforts from Nov 1939 but didn't give up the last Vildebeest biplanes until Feb 1940. To Ceylon Feb/Mar 1942.
39 - began to receive Beauforts while in Egypt in Aug 1941 to operate alongside Maryland's, the last of which were given up in June 1942.
42 - traded its traded Vildebeest for Beauforts in April 1940. To ME June 1942 where it surrendered its surviving aircraft to other units on 1 Sept. To FE Oct 1942.
47 - began conversion from Wellesley to Beaufort in July 1942 while in Egypt, a process not completed until Mar 1943.
48 - while it had Beauforts on charge May-Oct 1940 alongside Ansons, it never became operational on the former.
69 - while it was a recce unit it received a handful of Beauforts destined for 39 sqn while on Malta in Aug/Sept 1941

86 - swapped Blenheims for Beauforts in June 1941, but only began anti-shipping operations in Nov. Sent its aircraft to the Med in July 1942 to replace losses there and then re-equipped with Liberators.
217 - swapped Ansons for Beauforts between May & Dec 1940. In May 1942 ground crews left for Ceylon. Aircraft followed in June, but were held at Malta to cover Harpoon / Vigorous & Pedestal convoys, with crews reallocated to other ME squadrons.

It was intended to re-equip 415 & 489 with Beauforts in late 1941, but a shortage of aircraft meant they never became operational on the type, receiving Hampdens instead in early 1942.

 

[Reluctant Poster]

Indeed. I don't think British aerial torpedoes ever sank anything larger than a destroyer at sea. Yes, they scored important torpedo hits, such as those on the battleships Bismarck and Vittorio Veneto, cruisers Lützow, Pola and Trento (later scuttled), but the British had nothing like the success against heavy warships the Japanese managed with aerial dropped torpedoes. Had it not been neglected, RAF Coastal Command might have been the dominant aerial torpedo arm in 1939-40.

Opportunity. The RN and RAF were fighting a very different war than the IJN. Three of the ships sunk by the IJN were the more vulnerable aircraft carriers that the British simply did not have to opportunity to attack. In addition their enemies didn't come out to play very often, whereas the IJN was facing an opponent that was spoiling for a fight and was more that willing to put their ships in harms way.
I should have given more nuanced definition as to what I meant by sunk by aerial torpedoes. It actually means contributed to the sinking. Major warships were difficult to sink and generally required multiple hits, often from different weapons. The Prince of Wales suffered bomb hits and near misses but the primary cause was the torpedoes . The same can be said for the Repulse and the Lexington. In those cases the aerial torpedo gets most of the credit. However the Yorktown was actually sunk by submarine torpedoes and the explosion of the Hammann's depth charges while the USN was attempting to salvage her. The Hornet was also struck by multiple bombs as well as three torpedoes but wasn't sinking even after being struck by multiple US torpedoes. She was finally abandoned due to the approaching Japanese who finished her off. In those cases, similar to the Bismarck, the ships were sunk because aerial torpedoes put them in a vulnerable position.
Your final point is well taken. The time when the Germans did risk they heavy ships was very early in the war at which time the British were ill prepared to take advantage. The Channel Dash might have turned very differently had a Coastal Command strike wing existed.
The other aspect that should be ignored is that the primary use of British aerial torpedoes was against merchant shipping. Their effects on the enemy were significant and dwarfed the IJN achievements in that area. Sinking warships are a means to an end. The real end game is denying the enemy use of the sea while using it for your own purposes.
The following is a list of major warships hit by British aerial torpedoes

 

[Reluctant Poster]

When the enemy prefers to stay tucked up in port behind his AA defences, you either have to attack him there (Taranto, Brest & Dakar) or wait till he decides to come out.

And when the larger Axis warships did come out to play in the Atlantic & Med on those few occasions, there was the general shortage of carriers in the right place at the right time (none in the Med East of Malta from May 1941 to July 1943 for example) and only a handful (4 IIRC) of FAA shore based Swordfish / Albacore squadrons on Malta and in Egypt (with those on Malta suffering heavy losses in Lutwaffe bombings).

The RAF was also short of modern torpedo bombers throughout the 1939-42 period. The Beaufort only entered service in Nov 1939, becoming operational about April 1940. The first of these were not sent to the Med until late 1941. Such was the shortage of those aircraft Wellingtons & Hampdens had to be converted to fill the gap in 1942.

But still the following major Axis ship torpedoings by British aircraft come immediately to mind:-

Battleships:-
Bismarck (obviously!)
Gneisenau (at Brest 6 April 1941 by an RAF Beaufort. The pilot won a VC for that attack but sadly lost his life doing so)

Conte di Cavour (sunk at Taranto)
Duilo (Taranto)
Littorio (torpedoed twice - Taranto by the FAA and at sea in June 1942 by an RAF Wellington during Operation Vigorous)
Vittorio Veneto (at Matapan)

Richelieu ( French, at Dakar July 1940 by a Swordfish from Hermes)

Cruisers:-
Lutzow (June 1941 off Norway)

Trento (during Operation Vigorous - later sunk by a sub)
Pola (Matapan - later sunk by battleships)

Destroyers:-
There were 4 Italian destroyers torpedoed in ports in 1940 by the FAA.

These are the successful torpedo missions. Others were flown against major Axis warships that proved unsuccessful. Channel Dash in Feb 1942, strike on Prinz Eugen in Norwegian waters in May 1942 come to mind.

I didn't see your post before I posted mine I have duplicated much of the information you present here!

 

[Reluctant Poster]

Opportunity. The RN and RAF were fighting a very different war than the IJN. Three of the ships sunk by the IJN were the more vulnerable aircraft carriers that the British simply did not have to opportunity to attack. In addition their enemies didn't come out to play very often, whereas the IJN was facing an opponent that was spoiling for a fight and was more that willing to put their ships in harms way.
I should have given more nuanced definition as to what I meant by sunk by aerial torpedoes. It actually means contributed to the sinking. Major warships were difficult to sink and generally required multiple hits, often from different weapons. The Prince of Wales suffered bomb hits and near misses but the primary cause was the torpedoes . The same can be said for the Repulse and the Lexington. In those cases the aerial torpedo gets most of the credit. However the Yorktown was actually sunk by submarine torpedoes and the explosion of the Hammann's depth charges while the USN was attempting to salvage her. The Hornet was also struck by multiple bombs as well as three torpedoes but wasn't sinking even after being struck by multiple US torpedoes. She was finally abandoned due to the approaching Japanese who finished her off. In those cases, similar to the Bismarck, the ships were sunk because aerial torpedoes put them in a vulnerable position.
Your final point is well taken. The time when the Germans did risk they heavy ships was very early in the war at which time the British were ill prepared to take advantage. The Channel Dash might have turned very differently had a Coastal Command strike wing existed.
The other aspect that should be ignored is that the primary use of British aerial torpedoes was against merchant shipping. Their effects on the enemy were significant and dwarfed the IJN acivernets in that area. Sinking warships are a means to an end. The real end game is denying the enemy use of the sea while using it for your own purposes.
The following is a list of major warships hit by British aerial torpedoes

I also looked at the major warships sunk by the much maligned Mark 13 torpedo and I was surprised at the results. Apparently it wasn't as bad as its reputation. It certainly didn't have many of the problems the Mark 14 had. Its record against Japanese warships was actually better than vice versa. Admittedly most of theses successes occurred later in the war but it still have some success in 1942 and its early failings had as much to do with the shortcomings of the Devastator as the torpedo itself.

 

[Shortround6]

Admittedly most of theses successes occurred later in the war but it still have some success in 1942 and its early failings had as much to do with the shortcomings of the Devastator as the torpedo itself.

Failure to get into a suitable attack (drop) position can be be for several reasons. Including inadequate escort. The Devastator was never really available in large numbers. Only 130 built. About 100 still available in In Dec 1941?
By June 1942 around 80 were left and they used 41 at Midway with the well known results.
Trying to find how many torpedo planes the Japanese had at Midway with little success.

A failing of the MK 13 in 1942 was the need to slow down to 115kts to drop the torpedo. However Nobody else was much better or had only recently improved things. The late war MK 13 drops were at much higher speeds (and higher altitudes).

Not saying the Devastator was great, Navy issued the requirement for the replacement in 1939. It does get the blame for a number of things that were not it's fault.

 

[EwenS]

See the Navweaps page about the Mark 13 and in particular this report on tests in 1941 & mid-1943.

"....Unfortunately and unlike the Mod 0, the Mod 1 proved to be an unreliable weapon, with only one of ten torpedoes dropped by VT-6 during an exercise in July 1941 having a hot, straight and normal run. Of the others, four sank and could not be recovered while the other five experienced erratic runs.

These problems continued into the early war years, with a mid-1943 analysis of 105 torpedoes dropped at speeds in excess of 150 knots found that 36 percent ran cold (did not start), 20 percent sank, 20 percent had poor deflection performance, 18 percent gave unsatisfactory depth performance, 2 percent ran on the surface and only 31 percent gave a satisfactory run. The total exceeds 100 percent as many torpedoes had more than one defect. The early models were further handicapped by the need to drop them low and slow - typically 50 feet (15 m) and 110 knots which made the torpedo planes carrying them vulnerable to attack.

These problems were greatly reduced by the latter years of the war. Torpedoes had fin stabilizers, nose drag rings and tail shroud rings added, all of which worked to slow the torpedo after it was dropped so that it struck the water nose-first and at an acceptable speed. These improved the drop characteristics such that the recommended aircraft maximum launch parameters were increased to a height of 2,400 feet (730 m) and a speed of 410 knots."

World War II Torpedoes of the United States of America - NavWeaps

www.navweaps.com

The aerodynamic modifications to the Mark 13 (drag ring, box tail and shoud) were only used in combination for the first time in Feb 1944 during Operation Hailstone against Truk.

Evolution of a Ship-Sinker

The Mk 13 torpedo emerged as a devastating weapon responsible for sinking a Japanese superbattleship at the Battle of Leyte Gulf and another one off Okinawa.

www.usni.org

 

[EwenS]

Failure to get into a suitable attack (drop) position can be be for several reasons. Including inadequate escort. The Devastator was never really available in large numbers. Only 130 built. About 100 still available in In Dec 1941?
By June 1942 around 80 were left and they used 41 at Midway with the well known results.
Trying to find how many torpedo planes the Japanese had at Midway with little success.

A failing of the MK 13 in 1942 was the need to slow down to 115kts to drop the torpedo. However Nobody else was much better or had only recently improved things. The late war MK 13 drops were at much higher speeds (and higher altitudes).

Not saying the Devastator was great, Navy issued the requirement for the replacement in 1939. It does get the blame for a number of things that were not it's fault.

At Midway about half of the Type 97 Kate TB (those on Soryu & Hiryu) participated in the early morning bomb strike on Midway Island while the remainder were held on Akagi & Kaga armed with torpedoes. Then came the confused decision making that led to torpedoes being swapped for bombs and back again and the return of the others to be rearmed with torpedoes. That was when US aircraft arrived to cripple Akagi, Kaga & Soryu. None of the torpedo armed Kates were launched from these carriers before they were destroyed as effective fighting units.

It was early afternoon, 1330, before Hiryu was able to finish rearming some of her Kates and was able to launch just 10 Kates (one with damaged fuel tanks and effectively on a one way mission) to strike back at the US carriers and finding Yorktown. 5 were shot down by the CAP and the other 5 succeeded in scoring two hits on Yorktown before returning to the Hiryu. This was the only torpedo strike made that day by the IJN.

At 1630 Hiryu was preparing to launch another strike due to take off at 1800, which included just 4 Kates armed with torpedoes. But it never got off as USN dive bombers turned up at 1703 and put 4x1,000lb bombs into her flight deck so ending any further chance to strike back at the USN using carrier air power.

 

[Reluctant Poster]

I am a heretic and I believe that the USN was correct not to put torpedoes on large cruisers. The heavy cruiser mounted Type 93s did more harm than good. In actuality they only sunk 2 allied ships outright (INN Java and DeReyter) and contributed to the sinking of two American heavy cruisers (USS Vincennes and Quincy). In addition they slightly damaged the USS Chicago. Those are the only 5 enemy ships they actually hit in the entire war. On the other side of the ledger they were instrumental in the loss of IJN heavy cruisers Mikuma, Furutaka and Chokai and of course Mogami infamously sunk a Japanese minesweeper, 3 transports and 1 hospital ship.

There are only two battles where the heavy cruisers actually hit enemy ships: Java Sea and Savo Island. At Java Sea they unequivocally sank 2 light cruisers. One was the INN Java which was basically a WWI German light cruiser and should not have been in the line of battle. The DeRuyter was better, being almost the equivalent of an HMS Arethusa. Neither of these ships could be considered first rate cruisers. I would posit that the shell damage to the HMS Exeter was more important to overall events than the loss of both of the Dutch ships.

As for Savo Island there were 3 ships struck by type 93 torpedoes fired from heavy cruisers. The most important of these were the 2 fired by Kako that struck the USS Chicago, one of which was a dud. While these caused minimal damage the effect they had was pivotal as the Chicago went into full panic mode and failed totally in its duty to warn the other ships and barely fired back before heading in the opposite direction from the battle.
This is the best possible place to be hit with a torpedo. The fighting efficiency of the ship was not impaired in anyway.

View attachment 736217


Savo Island was a gun duel with the torpedoes not playing a pivotal role. All the cruisers that were lost were damaged beyond salvation before any torpedoes hit. The torpedoes hastened the same inevitable loss as befell Astoria. The Vincennes, Astoria and Quincy all had uncontrollable fires with no means to combat them as the fire fighting mains were all destroyed.

From Vincennes damage report
"19. Just as the enemy searchlights were trained on VINCENNES at 0155, the main battery was directed to train out and fire. A minute later the first enemy salvo struck, hitting the bridge, the carpenter shop, the hangar, battle II and the antenna trunk. Fires were started in the carpenter shop and the airplanes in the hangar. From this time on the enemy was hitting continuously until he ceased firing at 0215.

20. Course was changed to the left and speed increased; however, at no time was it greater than 19.5 knots. About a minute later, direct hits were received on sky aft and sky forward, blowing the after director overboard. Attempts to extinguish fires failed as all fire main risers had been ruptured. Further hits started fires in the movie locker and the cane fender stowage in the after end of the searchlight platform. The fire in the cane fenders was very intense and could not be extinguished. About 0200, attempts were made to evade enemy fire by turning hard right. While in this turn, one torpedo hit (possibly two) was received probably from the submarine which was reported fired on by gun No. 1. No. 1 fireroom was put out of action at this time. While in this turn, the left side range finder hoods of turrets I and II were struck.

21. About 0205, when beginning to make a left turn, steering control was lost in the pilot house. Control was shifted to the after steering station. About this time all steam power was lost due to blowers either being destroyed or drawing smoke and flames from the fires amidships into the firerooms. Diesels were started and they supplied power to turrets I and III. They were still able to fire in local control. Numerous hits during the early part of the action put out most of the guns of the secondary battery.

22. About 0209 turret II was struck on the face plate by an 8" shell which penetrated without exploding and set exposed powder on fire. Another projectile hit the barbette of turret No. I on the starboard side and jammed the turret in train. At this time all turrets and secondary battery except turret III and gun No. 1 were out of action, and all power had been lost.

23. At this time, while still under heavy fire from the enemy, the ship began to list appreciably to port. The crew was about to abandon ship when all at once the enemy extinguished searchlights and ceased firing. During the next fifteen minutes the list increased rapidly and it appeared that there was no possibility of saving the ship. The Commanding Officer then gave orders to abandon ship. About 0250 VINCENNES capsized to port and went down by the head in 500 fathoms of water."

The torpedoes that struck were as follows:
Chicago: 2 torpedoes (1 was a dud) from Kako
Vincennes: 1 torpedo from Choika, 1 torpedo from light cruiser Yubari
Quincy: 1 torpedo from Aoba, 2 -21" torpedoes from light cruiser Tenryu

During the attack on the northern group the Chokai launched 4 torpedoes at 9,500 yards. 3 minutes later she opened fire. The torpedoes arrive at the Vincennes 5 minutes after the gun battle had begun. At this point uncontrollable fires were raging and extensive damage to the Vincennes had been done by Kako's gunfire. There are debates on how many torpedoes hit with one certain and 1 or 2 more which may have actually been shell hits below the water line. I'm inclined to believe that two or three torpedoes hitting out of 4 is a highly unlikely event.

The torpedoes which struck Quincy (1 Type 93 and 2 21 in) were launched well after the gunfire commenced and at a range of only 3,000 yards. An additional Type 93 stuck the Vincennes 15 minutes after that battle started and it was fired from a range of only 2,400 yards.

The battle of Savo Island was decided by the 8" guns of the Japanese heavy cruisers not their torpedoes.

Over 80% of the type 93 hits in WWII were launched from destroyers and there is where the real value lies.

I did some more research and came up with this table comparing the pluses and minuses for cruiser mounted type 93 torpedoes.

There are some changes from the previous post. Investigation of the Choika wreck indicate that its torpedoes did not explode. Suzuya has been added . Suzaya wasn't actually hit but rather shrapnel from a near miss ignited her Type 93s.

 

[Thumpalumpacus]

I also looked at the major warships sunk by the much maligned Mark 13 torpedo and I was surprised at the results. Apparently it wasn't as bad as its reputation.

I was told by a member here that the Mk 13 used a different initiator than the Mk 14, resulting in a modest improvement in reliability. I can't remember who it was who told me that, though.

 

[Thumpalumpacus]

Trying to find how many torpedo planes the Japanese had at Midway with little success.

Parshall and Tully (SS, p.90) have the number at 81, 27 aboard Kaga, 18 apiece aboard each of the other three flattops.

 

[RCAFson]

I also looked at the major warships sunk by the much maligned Mark 13 torpedo and I was surprised at the results. Apparently it wasn't as bad as its reputation. It certainly didn't have many of the problems the Mark 14 had. Its record against Japanese warships was actually better than vice versa. Admittedly most of theses successes occurred later in the war but it still have some success in 1942 and its early failings had as much to do with the shortcomings of the Devastator as the torpedo itself.
View attachment 781392

Ryujo:
"Loss of RYUJO

During the Battle of the Eastern Solomons, despite conflicting reports, the most reliable affirm three confirmed bomb hits and a fourth very probable, with one torpedo hit in the starboard engine room as per this diagram of the damage reported to RYUJO. What is of interest is how much of the damage was concentrated near the edge of the flight deck starboard, which might explain the lack of obvious damage in verticals noted in her TROM. Note the torpedo hit to starboard in the engine room and a bomb hit just forward of it in nearly the same area but likely breaching the transverse bulkhead and opening the aftmost starboard boiler room as well; the resultant inundation of both compartments causing great flooding. It is worth noting that one of the better attested U.S. torpedo hit claims is one on the port forward, and the Japanese do note an "effective near-miss" with underwater damage in this area. Another torpedo by luck passed under the stern." ( Ryujo | Nihon Kaigun )


One of the problems with 1942 Mk13 hit claims, is trying to sort out actual hits vs near misses by 1000lb GP bombs dropped by SBDs. The warhead weight of the 1000lb GP is almost the same as a Mk13's and the attacks by TBs and DBs were often simultaneous.

 

[Admiral Beez]

Your final point is well taken. The time when the Germans did risk they heavy ships was very early in the war at which time the British were ill prepared to take advantage. The Channel Dash might have turned very differently had a Coastal Command strike wing existed.

A late-interwar well-trained, well-equipped, dedicated maritime strike arm would have been useful in many cases in addition to the Feb 1942 Channel Dash. For starters, at Heligoland Bight in Dec 1939, and followed by countering Operation Sonnenblume before it reaches North Africa in Feb 1941, and (returning to Japan) detecting and hitting the Japanese landing ships as they embarked and departed FIC for Malaya in Dec 1941. As it was, the RAF started the war with no antiship armour piercing bomb larger than 500 lbs., no multi-engine monoplane torpedo bomber, and insufficient (to no) long range maritime reconnaissance/strike aircraft capable of closing the mid-Atlantic air gap in preparation for the entirely predictable (based on WW1 as precedent and Nazi Germany's rapid prewar u-boat construction) submarine campaign against the necessary convoys.

In 1939, this was the RAF's primary torpedo bomber.

In 1939, this was Italy's. Per Wikipedia, "following pioneering work by the "Special Aerotorpedoes Unit", from 1939 onwards, two torpedoes could be carried externally, though usually only one was carried."

And this was Japan's.

I have to wonder if it was the lack of powerful engines that kept the like of the torpedo-armed Beaufort or Hampden from entering service earlier.

 

[EwenS]

A late-interwar well-trained, well-equipped, dedicated maritime strike arm would have been useful in many cases in addition to the Feb 1942 Channel Dash. For starters, at Heligoland Bight in Dec 1939, and followed by countering Operation Sonnenblume before it reaches North Africa in Feb 1941, and (returning to Japan) detecting and hitting the Japanese landing ships as they embarked and departed FIC for Malaya in Dec 1941. As it was, the RAF started the war with no antiship armour piercing bomb larger than 500 lbs., no multi-engine monoplane torpedo bomber, and insufficient (to no) long range maritime reconnaissance/strike aircraft capable of closing the mid-Atlantic air gap in preparation for the entirely predictable (based on WW1 as precedent and Nazi Germany's rapid prewar u-boat construction) submarine campaign against the necessary convoys.

We have discussed a pre-emptive strike on the Japanese before they landed in Malaya before. Until the Japanese actually landed in Malaya (several hours before PH - but a day later due to the International Date Line) there was no way that Britain politically was going to make a pre-emptive strike and thereby become the aggressor.

As for RAF equipment, as discussed many times before, timing was everything. The 2,000lb AP bomb was developed interwar as was a dedicated torpedo bomber also able to carry it - the Beaufort which entered service in Nov 1939 and became operational in 1940. If only everyone, including Hitler knew war would begin in Sept 1939 & not 1942 or 1944.

No one expected to fight the Battle of the Atlantic as it evolved. It was no where near as predictable as you seem to think. The WW1 experience spoke to something different. Submarines were limited in size and therefore in range. The big Type XIV Milch Cows weren't ordered until May 1940 and didn't begin to commission until the end of 1941.

This is the area of unrestricted German U-boat operations in 1917:-

This is the area in which, broadly, Britain expected to fight its anti-submarine war in WW2 when U-boats had to be based in Germany. Ships would only be convoyed to / from a MId-Ocean Meeting Point on the edge of that area. And this is the area that U-boat activity largely fell into until about August 1940. Check out the maps of monthly sinkings on Uboat.net.

Ship losses by month - uboat.net

The U-boat War in World War Two (Kriegsmarine, 1939-1945) and World War One (Kaiserliche Marine, 1914-1918) and the Allied efforts to counter the threat. This section includes over 21.000 Allied Warships and over 11.000 Allied Commanders of WWII, from the US Navy, Royal Navy, Royal Canadian...

uboat.net

Mid-Ocean Meeting Point - Wikipedia

en.wikipedia.org

What changed was the fall of the French Biscay ports with the surrender of France on 22 June 1940 and the subsequent completion of Operation Aerial to withdraw the 2nd BEF on 25 June 1940. The first U-boat replenished and rearmed at Lorient between 7 & 13 July 1940. Only from that point on did the U-boat war move further west into the Atlantic. That meant the RN / Coastal Command had to escort convoys further out in steps before ending up escorting them the whole way. That increased the need for long range aircraft and more escorts to convoy ships all the way across the Atlantic.

The Fall of France was an event that was completely unthinkable pre-war. And as a result figured in no-one's planning. That impacted the design of aircraft & ships. And it impacted greatly on the number of U-boats that could be kept in / close to the operational area by reducing the journey times to / from those patrol areas (doesn't affect the number of U-boats actually at sea but makes each potentially more effective - see below).

I'm not saying that the Anson was the best aircraft for the job in 1939. Coastal Command was neglected pre-war. But with delays to Botha & Blenheim, the problem had been recognised and the Hudson acquired. But no one envisaged needing an aircraft with the range of a Liberator because the "Atlantic Gap" wasn't expected to exist because U-boats wouldn't be operating that far out into the Atlantic. Same with the RN. The Flower class corvette was designed for operations in waters relatively close to Britain's shores and was adequate for that purpose. Unfortunately the first of these were entering service as France fell and the war they were expected to fight changed. But it struggled in the wild winter weather further out into the Atlantic. Its problems were recognised and a new design for a larger more capable ship begun starting Nov 1940.

Why not build more Flowers earlier? When the purse strings loosened in 1936 the need was to spend the money on the complex fleet ships that would take time to build. It was always recognised that small utilitarian AS ships would not take long to develop & build so could be started later. So the design of the Flower began in early 1939, they were ordered from July, laid down from Oct 1939 with the first completing from April 1940.

As for U-boat numbers I think you have an unrealistic picture of the size of Germany's U-boat fleet based on mid-war numbers. In Sept 1939 Donitz had 26 ocean going U-boats out of a fleet of just 57. For most of the time to spring 1941, there were only about 20 U-boats at sea. It took until Aug 1942 before the number at sea reached 100 for the first time.

Combat strength of the U-boat Force - Kriegsmarine U-boat Operations - uboat.net

The U-boat War in World War Two (Kriegsmarine, 1939-1945) and World War One (Kaiserliche Marine, 1914-1918) and the Allied efforts to counter the threat. Over 40.000 pages on the officers, the boats, technology and the Allied efforts to counter the U-boat threat.

uboat.net

In the first 10 months of the war U-boats sank 397 ships. In the next 6 (encompassing The First Happy Time) they sank 331. That is a sign of just how much more effective they became after the fall of the French ports.

 

[EwenS]

In 1939, this was Italy's. Per Wikipedia, "following pioneering work by the "Special Aerotorpedoes Unit", from 1939 onwards, two torpedoes could be carried externally, though usually only one was carried."

View attachment 781516

Not sure where Wiki pulls some of this information from. The Italians were not so far advanced in their TB development as some of that Wiki page seems to suggest.
Osprey Publishing book which has a previews available on Amazon & Google books. It notes

https://www.amazon.co.uk/Savoia-Marchetti-Sparviero-Torpedo-Bomber-Combat-Aircraft/dp/1782008071

1. The new Chief Staff of the Regia Aeronautica appointed in Nov 1939 ordered the first batch of just 30 air launched Whitehead torpedoes "shortly after his appointment" and another 50 after Italy entered the war that had been allocated to Germany..
2. The experimental unit formed on 25 July 1940 took just 7 aircraft modified as torpedo bombers into service between 23 July and 5 Aug 1940. After that first unsuccessful mission to Alexandria in August, the unit had just 4 crews. It was retitled 278 Squadriglia Autonoma Aerosiluranti on 3 Sept 1940, (the surviving 4 crews earning it the nickname "Quattro Gatti"). It achieved its first hit (on the cruiser Kent) on 17 Sept. In the first 4 months it achieved 4 hits on 3 RN cruisers for an expenditure of 37 torpedoes and that one loss.
3. The first two training units formed in Oct / Nov 1940 and the next operational squadron in Dec, with others following in Feb, March, July & Nov 1941.
4. In practice, the SM.79 carried only a single torpedo for weight reasons.