The torpedo pilots used to say: "If you want make holes into something, call the dive bombers. If you want to sink a ship call the torpedo planes!"

But I think in reality the dive bombers were more effictive. Look at the losses of the torpedo planes in the Pacific area.

The Swordfish crews...very brave men. That bird worked wonders.

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Gotta love the "String-Bag", there no taking away from its' record. Great lift and a quiet(er), more accurate approach. Probably the longest lasting bi-plane.
I remember watching a show about Bismarck and it said the the craft was to slow for their AA guns to be accurately directed at them, so they came right on.
There was also a crew member (over 50%) hanging over the side of the plane to time the torpedo drop (so it would go into the wave/instead of "Porpoise" off it) to assure a good run. That it was, for it was the one that hit the rudder, and sealed Bismarck's fate.

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That's always struck me as being one of the "myths of WW2". An attacking torpedo plane is, by definition, heading straight towards its target. So all the defending guns have to do is aim straight at it and fire...

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I should have put a question mark behind that. I can see how hugging the waves and diss-apperinng and re-apperaing between swells, especially in nasty weather, (not to mention bobbing up and down/evasive action yourself) would inhibit AA efforts (especially with the "German" seperate anti aircraft/destroyer secondary gun set up), and leave them boys reaching for excuses.
I don't know enough about Bismarck and whether/how it's radar was used for AA.
It did get nailed though.

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Bomb v Torpedo. British Facilities.


In August 1942 there were three techniques which could be employed for torpedo sighting:-


1. Straight running – in which the torpedo runs straight through the water in the same direction as that in which it was dropped.

2. Gyro Angling – which involves dropping the torpedo aimed straight at the middle of the target, but as soon as the torpedo enters the water a mechanism comes into play which turns it through a predetermined angle to effect interception. A computer is required to determine the angular setting on the torpedo.

3. Constant bearing – which caused the torpedo, after release, to maintain a constant bearing relative to the target, both during the flight in air and run in water. This requires both aim-off and gyro angling devices.

Of these techniques the only one in use by the RAF at this time was the straight running method.

Experience proved that aircraft fitted with sights obtained better results than when no sights were used. This was the case in spite of the fact that the type of sight fitted to Swordfish aircraft, for instance, was a somewhat crude affair.

A controversy was started at this time on the subject of the comparative effectiveness of bombs and torpedoes and in due course a report was issued on ‘Air Attack on Merchant Vessels’ and the conclusions reached were:-

1. That bombing attacks on merchant vessels were, on the whole, more effective than
torpedo attacks and could be made more so in certain area’s by the use of the Mark
XIV bomb sight.

2. Medium level attacks (4,000 Feet) against merchant vessels with light flak were
economical in casualties and would be more effective if the Mark XIV sight was
used.

3. 500lb. M/C bombs appeared satisfactory in use.


The ‘B’ Bomb.

A lesser known weapon still in the development stage which had always been regarded hopefully as an anti-ship device was the “Buoyant Bomb” Its conception began to take practical shape in 1923, but after some 16 years of experiment and labour, the original design was completely abandoned and work began afresh on an entirely new model.

The primary object of the “B” bomb was to attack the bottom of a ship, which had been regarded up to now as generally immune from bombing attacks. The device was a self contained and truly buoyant component fitted withy sensitive horns, rather like a mine, which it was intended to drop at a certain distance ahead of a ship so that it would come up, after an interval, and strike the bottom. It was never intended that the bomb should hit the ship directly from the air as in the case of all other bomb types. The principle of detonation after a fixed delay was abandoned early in the development stage; the bomb was to explode on contact with the ship.

After intensive “B” bomb training six crews of No.415 RCAF Squadron in Hampdens carried out some operations against shipping off the Dutch coast, but observation of the actual results was very difficult, but from post war records it is known that no damage or sinkings resulted from any of the attacks made. It was eventually decided that until the Mark XIV sight, with its increased accuracy was available, the “B” bomb would be of no use.

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The Bismarck vs. Swordfish and the guns being unable to hit them due to slow speed is pure myth. From even an empirical viewpoint one can easily put to lie this silliness.
The Bismarck had just 8 4.1" AA guns per side that could engage a target. These were optically directed the battery having two directors per side. The battery could be controlled either enmass (eg., all 8 guns firing on a target) or split in two with 4 guns engaging two seperate targets. Which was being done isn't known.
In either case, the Swordfish approached at low altitude in poor weather and likely were not even spotted until they had approached within a mile or two of the Bismarck. But, let's say five miles. This is about 10,000 yards or about the maximum practical range of the Bismarck main AA battery. At just 120 miles per hour the Bismarck gets just two and a half minutes of fire before the planes reach her. This is about 50 shells per gun maximum, probably less. This means that realistically the Bismarck is probably only going to get to engage two to four of the attackers with the main battery with any likelihood of shooting them down before the attack is literally over. The smaller guns in the battery have even less time and less true effect as none of these is stabilized or has director control.
Basically, you can clearly see that the Bismarck travelling alone is extremely vulnerable to air attack and her defenses will not suffice to stop a determined attack.

... and not to reduce my admiration for the Swordfish crews in their attack on Bismarck, but AA fire was the only German defense they had to contend with - there was no CAP pouncing down on them, as the Devastator's faced at Midway.

Given the average reliability of air launched torpedoes during WWII, I'd go for dive bombers.

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This extract from my book Rapid Fire: the Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces might be of interest:

Even at the beginning of the 1930s there was some concern about the adequacy of the British weapons. The problem was considered by the Naval Anti-Aircraft Gunnery Committee, which produced a report in April 1932.

The Committee went into great technical detail in calculating the effectiveness of different guns. They took into consideration such matters as the nature of the threats, the time during which aircraft could be brought under effective fire by different weapons, the range and rate of fire of the guns, the effectiveness of shells and fuzes, and appropriate methods of fire control. Their conclusions make interesting reading.

Three types of attack were considered; precision (i.e. level) bombing, torpedo bombing, and close-range attack with bombs or machine guns. With remarkable prescience, the Committee also identified a further potential risk:

"The possibility of explosive aircraft being manoeuvred by human pilots to hit ship targets cannot however be ruled out. It is reported that, sooner than accept defeat, ramming other aircraft is a recognised principle among Japanese pilots.

Note:- The Air Ministry regard this idea as exceptionally secret and would prefer that it be not generally promulgated"

It was clear that the Committee considered such attacks to be potentially extremely difficult to deal with, a concern fully justified by the experience of a dozen years later.

In considering short-range defence, the Committee was most concerned about torpedo bombers, calculating that any weapon system able to cope with them would be able to deal with other forms of short-range attack easily enough. Exercises between 1928 and 1931 had shown that the probability of a torpedo bomber hitting a ship was only 10% at 1,250 yards (1,140m) but rose to 30% at 1,000 yards (910m), 50% at 750 yards (690m) then increased very sharply to 85% at 600 yards (550m).

This led to a demand for a range of 2,500 yards (2,300m) from automatic AA guns, in order to achieve the aim of certain destruction of an aircraft with 10 seconds of firing at a mean range of 2,000 yards (1,820m). It was estimated that an aircraft dropping a torpedo from 1,200 yards (1,100m) would already have been under fire from such weapons for 17 seconds, which was assumed to be more than enough time to shoot it down.

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Great info Mr. Williams !

I was trying to make reference to sea conditions and their effect on defensive fire.
A book called Battle of the Atlantic (Hughes & Costello) states (during the Bismarck attacks), at 3 PM 14 Swordfish launched and an hour later mistakenly attacked "Sheffield".
A second flight of 15 Swordfish of Nos. 810, 818, and 820 Squadrons Fleet Air Arm led by Lieutenant Commander T.P. Coode took off with orders to make contact with "Sheffield" first before making their attack.
"Just before 8 PM the Swordfish paired up and started a series of attacks on the Bismarck from all sides."
"13 torpedo's were launched with 2 hits, including the one jamming the rudders and wrecking the steering gear." "All the aircraft managed to find the carrier but, with the Ark Royal's flight deck rearing some thirty feet in the rough sea, four planes were wrecked in the heavy landings."

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The sinking of HMS Prince of Wales and HMS Repulse off Malaya in Dec 1941, was a textbook demonstration of coordinated torpedo and bomb attacks. Although the more manoeuvrable Repulse proved a harder target to hit, her outdated AA defences allowed straight-running bombers to score vital hits. The torpedo bombers then finished her off. Prince of Wales was the victim of a freak torpedo strike which wrecked her steering gear and took out the power which kept her 5.25" AA batteries firing. The patterns flown by the torpedo planes were designed to split the AA fire and render it less effective. AFAIK, something like 80+ sorties were made by the Jap planes.

Cheers,
Klive.

The PoW / Repulse action really demonstrated only two things:

First, that AA defense by ships needed to:

A. Be coordinated among the entire group, the ships acting in unison. PoW and Repulse acted individually maneuvering independently in this action decreasing their AA effectiveness.
B. Include escorts. This was a major, major failing of the Royal Navy. Most of their destroyer force had very limited anti-aircraft ability. In 1941 most British DD's lacked an effective main battery for AA defense. The guns were almost universally single purpose weapons and all lacked director AA fire control.
In the incident in question, the DD's present were all some of the oldest classes in the RN and none had any really useful AA systems aboard. This meant they contributed little or nothing to the defense of the capital ships.
C. Ships needed to have effective steaming formations to counter enemy air attack. Here there was no air defense formation nor were the ships available maximizing their air defense systems.

And secondly,

That a ship's air defense systems could be overwhelmed in a coordinated strike, particularly one that did not suffer losses to a CAP.

Looking at PoW for example, we find the same problem Bismarck had. PoW has four directors for the main 5.25" AA battery (Repulse had just three for her 4" guns) and the 40mm suite is optically directed in local control. This means that at best PoW can effectively engage maybe eight targets, four per side and likely probably less at any given time. With say a dozen or more targets closing the defenses are overwhelmed and PoW is going to get hit by the leakers that did not get engaged along with any survivors from the AA engagement.
Once PoW took some serious damage she was pretty much finished.

The best defense against air attack was a coordinated CAP. If this engaged at 30 to 40 miles out, and preferably more, a typical strike met by a reasonably sized CAP was pretty much finished. A handful of survivors might make the target and the outcome is likely in the defender's favor.
The next best option is a tight AA formation where the ship's fight as a group. There is an action by the US in 1944....Empress Augusta Bay... where four light cruisers and four destroyers are attacked by 80+ G4M bombers out of Rabual. This group managed to shoot down over 20 (admittedly they had the advantage of VT fuzes) and drove off the rest suffering only one bomb hit injuring three crewmen in return. The difference is stunning.
Had PoW and Repulse had an effective AA screen and maneuvered in formation they too might have survived their air action. Poor tactics and lack of an AA screen did them in.

I suspect that the newer concept of the dive bomber was more effective in the pacific than elsewhere because the Pacific was primarily a carrier battle and flat tops are uniquely vulnerable to dive bombing. Torpedo bombers held sway longer in Europe mostly because the primary targets were slow moving convoy ships and smaller war ships which were harder to hit and sink with dive bombing but were very vulnerable to a single torpedo hit.

There is also the issue of kit; the British didn't use stringbags on their carriers because they were perfect for the job they used them because they were all that was available. In the pacific both sides had a reasonable dive bomber from the outset while certainly in the case of the US their torpedo's were very poor and unreliable (I accept that is not the case with the Japanese models)