Why the Skua Only Carried a 500lb Bomb (1 Viewer)

[Reluctant Poster]

View attachment 717103Ouch.
Too bad FAA didn't have SBDs, that was without such bad habits, and was maneuverable

He could have done to the ME-109s what Swede Vejtasa did in his Dauntless against Zeros

The Swede Vejtasa claims are debunked by Lundstrom in his book "The First Team"

 

[Reluctant Poster]

Contrary to what you extracted from Campbell, I took my information from the "United States Bombs and Fuzes Pyrotechnics" Manual dated 1 Sept 1945.

Section I Part II - US Army 'M' Series bombs lists the M52-63 weapons (page 12 of the document onwards). Converted from "seacoast artillery shells" of 10-14" diameter. Coastal defence guns were a US Army responsibility not a USN one, although a few of the guns had originally been built for the USN.

Section I Part III - US Navy 'MK' Series Bombs lists no AP weapons.

Section I Part IV - US Army-Navy 'AN' Series Bombs lists the AP 1,000lb Mk 33 & 1,600lb Mk 1

 

[planespotting]

The view over short nose of the Skua Mk.I prototype must have been excellent for taxiing, landing, and searching for ships or other aircraft.

Though it looks alarmingly short in level flight- perhaps the centre-of-gravity issue was just to do with optimising it for cockpit view, and not as I'd suspected the designers sensibly allowing for a heavier engine...

Incidentally, I suspect that the flat windscreen section on the Skua reflected worries about optical distortion. The SBD had a through windscreen sight, so there was no distortion. I believe that the D3A had an external telescopic sight and I hope that the optical designers would cancel any distortion from the canopy .

I can believe it - the sideways-canted panes are presumably for looking at the deck, though it would make sense that they'd try to do two useful things at once (seems like part of the package on a dive-bomber / fighter hybrid!).

No. The reasons for two-seat fighter-reconaissance aircraft are well-established.

Oh, there were well-established reasons that weren't to do with "RDF", but when you discover surface-search radar in September 1937, and in March 1938 you decide you need to adapt the most readily available large, long-range two-seater as the centrepiece of your carrier force, it's not completely impossible that there was some connection between these two things that just wasn't talked about that openly...

Now yes, there are other possible explanations, there's no indication the Fulmar ever actually carried ASV (though I am coming across odd references to them shadowing enemy capital ships at night in the Atlantic) and to an extent I'm just indulging my habit of towing gunnery targets, but it seems like an interesting juxtaposition...

No. Emerald, having spent the first part of 1942 in the Indian Ocean, returned to Portsmouth in Aug for a refit that lasted through until April 1943. During that refit she was fitted with:-
Type 281 air warning radar (aerials on both masts - the after one becoming a tripod to support the aerial)
Type 273 centimetric surface search (lantern on bridge)
Type 285 main gunnery radar
Type 282 x2 for the pom pom directors (she had 2 quad pom-poms fitted during this refit)
And Kingfisher replaced the Osprey

Following that refit she went back to the Indian Ocean until March 1944. At that point she returned home and her catapult & aircraft facilities were removed and her AA armament further strengthened before D-Day.

Thanks for the information! Though to my chagrin, I'll observe that if I'd bothered to do more than guessing wildly on the internet, I could have looked up the gist of it in Friedman's British Cruisers and saved you the need to reply...

That said, it's not as impressive as it sounds; it's mostly anti-aircraft stuff - Type 281 at the masthead for angle, Type 285 on the director for ranging and Type 282 on the pom-poms themselves, plus associated IFF and D/F kit, all of which is a lot of effort for, what, two quad 40mm?

Now, as you say, she needed second tripod mast added aft to carry the receiving end of the Type 281, presumably because the existing foremast wasn't robust enough for the integrated Type 281B; the surface-search lantern is on top of the charthouse, the only other place for it and a rather low position which would limit range, and there's no proper surface-gunnery set, because there's simply no room for one; so I wasn't completely wrong to hazard a lack of "useful space for radar" which might add to the continued utility of a catapult plane in its traditional roles of surface-search and spotting (a photo of Emerald in Friedman's Naval Firepower claims the lantern is actually only the shorter-range periscope-detecting Type 271, too, though that could be a misidentification; the photo's inaccurately dated "March 1942", which confused me for a while; but the full version on the IWM museum website features the tripod mast aft, confirming that it follows the refit)...

Apologies for the successive edits in this section, too...

The old WW1 vintage cruisers operating in the Indian Ocean were amongst the last to be fitted with radar due to the low priority that theatre had for the equipment. By the end of 1942 most either had or were being taken in hand to fit radar of some kind as part of the regular refit process.

They presumably also had the same limited charthouse/topmast space as Emerald, even if it wasn't nearly so limited as I'd casually imagined...

Emerald was refitted 1934-36 as part of which she received SIIL catapult and subsequently operated Hawker Osprey (1934-37), Fairey Seafox (1937-42) and finally the Kingfisher (1943-44). The catapult was not powerful enough to launch a Walrus, so hence the need for the Kingfisher in 1943.

Aye, that's what I said!

Different navies had different doctrines about the use of seaplanes / flying boats on capital ships and cruisers.

For the Japanese the seaplane carried on their 8" cruisers was the eyes of the fleet to find the enemy, not the carrier aircraft. Those cruisers would be operating with the fleet alongside the carriers. Take a look at the early carrier operations in WW2. It was Midway before Soryu carried a pair of D4Y-1C Suisei (Judy) aircraft for reconnaissance and 1944 before the C6N Saiun (Myrt) appeared, by which time it had no carriers to operate from.

As for Tone & Chikuma the plan for them was modified while they were building and they were redesignated "scouting cruisers" intended to carry 2 types:-
1. long range for scouting (2 or 4 3 seat aircraft) and
2. shorter range for spotting and AS work (4 2 seaters).
i.e. 6-8 aircraft instead of the usual 4 carried by the heavy cruisers.

To ensure that this increased aircraft complement wasn't damaged by the ship's own guns (more aircraft meant more space required midships to aft) the main armament was concentrated forward. They spent a large part of their wartime careers working with the Japanese carriers. Pearl Harbour & operations in the Indian Ocean in 1942 for example.

Japanese operations in 1942 revealed major weaknesses in their scouting capacity and procedures. Look at operations in the Indian Ocean and at Midway for the proof. One reaction was to see the need for another scouting cruiser. As Mogami had been so heavily damaged at Midway, losing one of her after turrets, she provided an excellent opportunity and platform to augment the scouting forces. As reconstructed she had a capacity of 11 aircraft but initially only carried 7.

As for the conversion of the battleships Ise & Hyuga, the Japanese intention was completely different and had nothing to do with scouting. Their conversion was a reaction to the loss of the carriers at Midway and an attempt to replace them i.e converted battleships as auxiliary carriers not as an increase to the scouting capacity. Various proposals were considered involving full conversion to flush deck carrier with island, removal of 4 turrets and rebuilding aft of the funnel or removal of just turrets 5 & 6. The latter route was chosen because:-
1. shorter time required for conversion
2. minimal effect on other warship construction
3. moderate material & labour cost.

As completed they were intended to operate as a pair as part of a larger carrier group with Junyo & Ryuho, each with 11 modified D4Y2 Suisei (Judy) dive bombers and 11 E13A Zuiun (Paul) floatplanes. Once launched the Judys would either land on a carrier in the group or fly to a land base. Cranes were provided to recover the floatplanes. Although completed in late 1943, their intended airgroup, the 634th Air Group, did not form until May 1944, so too late for the pair to participate in the Battle of the Philippine Sea. They only once seem to have embarked part of their air group for training. When they sailed in Oct 1944 as bait for Japanese operations in the Philippines they sailed without aircraft.

The full story of their conversion was set out in an article by Hans Lengerer, an expert in Japanese warships, in Warship 2009 published by Conway.

I'll look that up with interest... I've never found a way into the Japanese material, except that I'd acquired the sense that a surprising amount of what the USN thought they knew after 1945 was sourced from simple guesswork and debriefings of IJA officers who had little real knowledge of what the IJN were doing...

In the USN, aircraft like the SOC Seagull, OS2U Kingfisher and later SC-1 Seahawk had a mix of roles including recce (increasing the horizon of the cruiser force), gunfire spotting for the battleships and even AS work. For the USN pre-war doctrine called for the limited number of carriers to operate individually and separately from the battleships. But the main scouting force was contained in the 18 plane VS scout squadrons on the carriers themselves.

For the RN many of the cruisers would be operating alone, patrolling the sea lanes and a spotter plane increased those horizons in pre-radar days. As WW2 went on that patrol function was taken over by aircraft like the Sunderland, Catalina and Liberator. The best examples are the sea lanes of the Indian Ocean. But in a fleet scenario, with a carrier involved the main search activity was carried out by its aircraft, not the spotters on the battleships and cruisers. That way the recce effort could be directed more efficiently and was not so reliant on the sea conditions.

Oh, I understand the purpose of the spotter in pre-radar days - I'm just meditating on the fact that that catapult floatplanes off capital ships and cruisers continued to have a use as search-radar platforms covering a larger area (and also preventing the capital ships from hanging out a big flashing "here I am" sign on the masthead), which isn't as immediately obvious...

The first airborne radar available to the FAA was ASV.II which began to be fitted to Swordfish in the Home Fleet and Force H in March 1941. By the time of the Bismarck chase all 9 aircraft in 825 squadron on Victorious had been fitted but only a handful in the squadrons on Ark Royal. As for not using a Walrus during the Bismark chase I suggest you take a look at the sea conditions that existed throughout most of the time. They were awful. There would have been no means of recovering any floatplane even if they could be launched. The Germans did not operate their Ar 196 aircraft either.

That's part what I meant by "obviously they'd found masthead radar more useful than the Walrus in the Bismarck chase in North Atlantic conditions". Excuse the ironic understatement?

There is anecdotal evidence of a Walrus deck-landing on HMS Argus, though (an over-the-horizon signal-flag to Exeter and Vian?)...

As for Formidable at Cape Matapan, her aircraft lacked radar. For technical reasons that I've never seen explained, ASV.II wasn't made to work on the Albacore until the latter part of 1941. The Swordfish she had on board had been collected in Egypt in February as replacements due to a lack of Albacores in theatre. And Matapan was a night action. Formidable's aircraft had already succeeded in torpedoing Vittorio Veneto in the afternoon and the second strike launched in daylight and went in just after dark to torpedo Pola.

Even in 1942 ASV.II was not a universal fitting. During Somerville's search for the Japanese fleet in April 1942 none of Indomitable's and only some of Formidable's Albacores were radar equipped. A few years ago during some research into this period I discovered a corelation between the aircraft production dates and the complement on each ship. Then in late April there was a reshuffling of airframes between the carriers for unexplained reasons. I suspect however that it might have been about spreading the radar equipped aircraft more evenly through the fleet. Illustious when she arrived in April brought radar equipped Swordfish.

The RN did not so much reject the floatplane as found it no longer had a purpose. Naval warfare had changed. Cruisers patrolling the sea lanes virtually ended in early 1944 for reasons noted above. The submarine not the raider was then the threat even in the expanse of the IO and cruisers made better targets than sub killers. Cruisers were operating almost exclusively as part of a fleet with an increasing number of carriers available to protect them. Those carrier aircraft provided all the air recce and gunfre spotting required (as during Operation Inmate in June 1945 when cruisers of the RN, RCN & RNZN bombarded Truk Atoll with spotting from aircraft on Implacable). Postwar battleships and then cruisers just faded away.

I'd say the reason the surface raider wasn't the threat was largely due to terrible procurement decisions by Raeder, who was trying to continue the campaign he'd been planning with von Hipper in 1918... but that's another discussion...

The details on the actual outfit of the aircraft are fascinating though, and obviously quite new to me - much appreciated!

As pointed out above it could not be further from the truth.

The only Fulmars to get radar were those converted as night fighters.

So it seems, but that doesn't strictly mean they weren't supposed to...

 

[RCAFson]

I don't think the USN would be interested in adopting an aircraft the RN had already declared as obsolete as a torpedo bomber in the same year. however, let's roll with your suggestion anyway.


The problem with using the Swordfish as a scout aircraft within the vast Pacific ocean is its poor range – in this respect the Vindicator and Dauntless certainly had the advantage. Why would the USN use the Swordfish – or TBD – as a scout plane when there are far superior aircraft for the role already available?


Not true at all. I don't think the British used the Swordfish as against surface warships very much (apart from the ASW role perhaps?), and I certainly don't recall it being used as a dive bomber against German/Italian warships – could you provide more details on the Swordfish's divebombing record? The Swordfish was a bit slow to be flying over groups of Japanese warships, surely? In any case, most combat aircraft can be used as a dive bomber, the Spitfire was used as a dive bomber, as was the P-40 and Ju-88. Not that you actually need to carry out bombing attacks on enemy shipping using dive bombing tactics.

Why not rephrase your opening suggestion like so: "Let's replace the Swordfish used at used in the Atlantic and Mediterranean with Swordfish…"? Would the TBD not have performed equally as well as the Swordfish during the Battle of Taranto or during the sinking of the Battleship Bismarck or against all other Axis surface shipping (when carrying the right torpedoes)?

Hypothetically giving the USN Swordfish (but preferably Albacores which the FAA intended to be it's successor) in lieu of the TBD allows us to explore how it differs from the TBD and what additionally capabilities it would have offered the USN.

The Swordfish had better range than the TDB but most importantly it carried ASV radar and so could conduct recon at night and in bad weather. In any event USN day recon patrols seldom exceeded the Swordfish's range.

The torpedo was certainly the preferred weapon against surface ships but it was used fairly often as a DB: From the Pilot's Notes for the Swordfish:
"36. Flying limitations
(i} The aircraft is designed for manoeuvres appropriate to a
torpedo-dive bomber..."

To quote wikipedia:

"The Swordfish was also capable of operating as a dive-bomber. During 1939, Swordfish on board HMS Glorious participated in a series of dive-bombing trials, during which 439 practice bombs were dropped at dive angles of 60, 67 and 70 degrees, against the target ship HMS Centurion. Tests against a stationary target showed an average error of 49 yd (45 m) from a release height of 1,300 ft (400 m) and a dive angle of 70 degrees; tests against a manoeuvring target showed an average error of 44 yd (40 m) from a drop height of 1,800 ft (550 m) and a dive angle of 60 degrees.[14]"

In one operation a Swordfish squadron from HMS Eagle were used to sink two Italian destroyers and cripple several others that were operating in the Red Sea in early 1941. The Swordfish as DBs were carrying 6 x 250lb bombs each, and this proved extremely effective. The Swordfish was used quite often as a strike bomber in the DB role, as was the Albacore and both were designed for this role.

The TBD, due to it's STOL characteristics was not operable from the slower carriers and shorter flight decks of most FAA carriers and it's wing fold design would have prevented it from being carried in the hangars of most of the modern carriers including Victorious and Ark Royal. It also had less range than the Swordfish as it could not carry aux internal or external fuel tanks. It's unlikely that it could carry ASV radar. The TDB was not stressed for DBing and so could not undertake the FAA's preferred torpedo attack profile using a DB approach just prior to weapon release. With it's low stressed monoplane airframe it would have been very difficult for it to have undertaken the Taranto raid, for example, as it gained speed too rapidly whilst descending to weapon release altitude.

 

[RCAFson]

Now yes, there are other possible explanations, there's no indication the Fulmar ever actually carried ASV (though I am coming across odd references to them shadowing enemy capital ships at night in the Atlantic) and to an extent I'm just indulging my habit of towing gunnery targets, but it seems like an interesting juxtaposition...

There was a NF variant of the Fulmar II that was fitted with AI radar. The Fulmar was designed for night operations but was not fitted with ASV radar AFAIK.

 

[EwenS]

Thanks for the information! Though to my chagrin, I'll observe that if I'd bothered to do more than guessing wildly on the internet, I could have looked up the gist of it in Friedman's British Cruisers and saved you the need to reply...

That said, it's not as impressive as it sounds; it's mostly anti-aircraft stuff - Type 281 at the masthead for angle, Type 285 on the director for ranging and Type 282 on the pom-poms themselves, plus associated IFF and D/F kit, all of which is a lot of effort for, what, two quad 40mm?

Now, as you say, she needed second tripod mast added aft to carry the receiving end of the Type 281, presumably because the existing foremast wasn't robust enough for the integrated Type 281B; the surface-search lantern is on top of the charthouse, the only other place for it and a rather low position which would limit range, and there's no proper surface-gunnery set, because there's simply no room for one; so I wasn't completely wrong to hazard a lack of "useful space for radar" which might add to the continued utility of a catapult plane in its traditional roles of surface-search and spotting (a photo of Emerald in Friedman's Naval Firepower claims the lantern is actually only the shorter-range periscope-detecting Type 271, too, though that could be a misidentification; the photo's inaccurately dated "March 1942", which confused me for a while; but the full version on the IWM museum website features the tripod mast aft, confirming that it follows the refit)...

Apologies for the successive edits in this section, too...


They presumably also had the same limited charthouse/topmast space as Emerald, even if it wasn't nearly so limited as I'd casually imagined...

There is little to distinguish Type 271 from Type 273 externally. Type 271 was intended for small ships and 273 for larger ships (cruiser and above). Derek Howse in "Radar at Sea" describes the difference as follows:-
"The big-ship set, dubbed type 273, was identical to type 271 except for the rwo 3ft circular mirrors (not stabilized in the earlier models) and a slightly larger lantern."


Type 271 aerial within the lantern:-

Type 273 aerial within the lantern:-

When it comes to looking at radar ranges in WW2 care needs to be taken in comparing like with like. Radars were upgraded as the war went on. Performance could vary from ship type to ship type. And that is before considering the quality of the operators.

The first Type 273 was fitted in the battleship Prince of Wales during her refit at Rosyth in June / July 1941 where it was carried high up in the ship between the forward high angle directors. Being mounted higher on a larger and more stable platform automatically helped increase range. Howse notes that the working range was 19 miles on the battlecruiser Repulse, 18 miles on the cruiser Euryalus and 14 miles on the destroyer Lively.

In comparison, a 271 carried much lower on a corvette could achieve about 6-7.5 miles against a destroyer and 2-2.5 on a submarine (not its periscope).

But as the war went on the performance of each of these sets was improved (differentiated by suffix letters). 271Q for example was first installed in the corvette Marigold in May 1942 as a replacement for one of the very first 271 sets. She was able to detect a sub at 5 miles. The first 273Q went into King George V in July 1942 and achieved 28 miles against the cruiser Cumberland and a submarine at 7.5 miles.

As for Emerald's armament it changed as the war went on (see Raven and Roberts "British Cruisers of World War Two" Appendix 2 War Modifications)

1939 - 7x6" single mounts; 3x4" single HA; 2xsingle pom-pom; 4xquad 0.5"
8/42-4/43 refit - remove 1x6" and all single pom-pom & quad 0.5". Add 2xquad pom-pom with associated directors and 6xtwin 20mm
3-4/44 - remove catapult and add 6 single 20mm

That was a fairly typical RN cruiser light AA armament for the period. The smaller modified Dido, Spartan completed in Aug 1943 had 3 quad pom-pom (one in place of Q turret in the original Dido class) and 6 twin 20mm. The three slightly larger modified Fiji class completed Jan-July 1943 had 3 quad pom-pom (one in place of the triple 6" X turret of the original class) and 8-10 twin 20mm.

Just by way of comparison a US Omaha class cruiser of similar age would have carried something like this in early 1943:-
10x6" (2x2 & 6x1 reduced from 12); 7x3"/50 singles; 2xtwin 40mm and 12x20mm singles (with 1x3" scheduled for replacement with a twin bofors when available).

Radar wise they carried a big SK warning radar (equivalent to Type 281) and a centimetric SG set for surface search (equivalent to Type 271/273). They also received 1/2 Mk 3 sets for gunnery fire control (equivalent of the RN Type 282/284/285 gunnery radars)

 

[planespotting]

There was a NF variant of the Fulmar II that was fitted with AI radar. The Fulmar was designed for night operations but was not fitted with ASV radar AFAIK.

I certainly haven't found anything to say otherwise, in terms of the aircraft as-deployed; lack of precision in published narratives made me curious, but EwenS clearly knows a lot more about this, and seems certain that they never had anything except the late AI variant...

For example, an attempt to find the Italian fleet in September 1941 began with two ASV-equipped "shadowers" of unspecified type followed by a twelve Swordfish and four Fulmars, with "ten ASV sets in the formation" - to me, that lack of speicficity looks curious, but I suspect it's simply being taken as read that all those ASV aircraft are Swordfish?

There is little to distinguish Type 271 from Type 273 externally. Type 271 was intended for small ships and 273 for larger ships (cruiser and above). Derek Howse in "Radar at Sea" describes the difference as follows:-
"The big-ship set, dubbed type 273, was identical to type 271 except for the rwo 3ft circular mirrors (not stabilized in the earlier models) and a slightly larger lantern."


Type 271 aerial within the lantern:-
View attachment 718633

Type 273 aerial within the lantern:-

View attachment 718634


When it comes to looking at radar ranges in WW2 care needs to be taken in comparing like with like. Radars were upgraded as the war went on. Performance could vary from ship type to ship type. And that is before considering the quality of the operators.

The first Type 273 was fitted in the battleship Prince of Wales during her refit at Rosyth in June / July 1941 where it was carried high up in the ship between the forward high angle directors. Being mounted higher on a larger and more stable platform automatically helped increase range. Howse notes that the working range was 19 miles on the battlecruiser Repulse, 18 miles on the cruiser Euryalus and 14 miles on the destroyer Lively.

In comparison, a 271 carried much lower on a corvette could achieve about 6-7.5 miles against a destroyer and 2-2.5 on a submarine (not its periscope).

But as the war went on the performance of each of these sets was improved (differentiated by suffix letters). 271Q for example was first installed in the corvette Marigold in May 1942 as a replacement for one of the very first 271 sets. She was able to detect a sub at 5 miles. The first 273Q went into King George V in July 1942 and achieved 28 miles against the cruiser Cumberland and a submarine at 7.5 miles.

Thanks again - I knew that Type 273 had a different aerial inside the lantern, but not what it looked like, or whether there was any external difference that might provide a clue.

But in addition... it turns out that the crew of Emerald wrote a helpfully technical review of their radar (for the September 1944 volume of the Admiralty Signals Establishment's Bulletin, "part 3" of the PDF). Amazing what you can turn up on google...

In summary...

They had a proper surface-search set Type 273QR, which they reported could detect Ramilles at ranges out to 25 nautical miles, and destroyers at roughly 15 nautical miles - this is pretty good, as for comparison Duke of York picked up Scharnhorst at just under 23 nautical miles (albeit perhaps in less radar-friendly sea-conditions); but it's all inside the horizon, which would make a catapult-plane necessary for over-the-horizon search. Also, it had limited rotation, and didn't cover the third of the horizon astern of the ship - I have no idea if this was typical of the type.

The Type 281 masthead air-search set was used as designed for angle and height-finding in the AA role, and seems to have worked as designed.

The Type 285 gunnery-direction radar (properly used for anti-aircraft ranging) was used as an improvised aft search set; though it's not entirely clear, it may have been used for surface gunnery as well, and presumably refined the rather imprecise angles of the search radar....

The Type 282 radar on the quad-40mms could be used to range on Emerald's own shell splashes, presumably from the main 6-inch guns - using a light AA as an improvised fire-control system to correct main-gunnery range appeals to me!

There was a Type 251M navigation beacon, little-used but useful to 27 miles, and an IFF set consisting of a Type 243 interrogator / Type 253 transponder, paired units that were designed to respond to their counterparts; the Type 243 worked well, picking up the IFF signal of their own floatplane to ranges beyond what the Type 281 could see, but their Type 253 automatically activated in response to it, and they were trying to work out a way to stop this. The F.V.1 D/F system hadn't detected anything except RN radars, and was completely jammed when any of Emerald's own AA sets were switched on.

The Emerald's floatplane carried "Mark III", from the context evidently ASV Mk.III.

As for Emerald's armament it changed as the war went on (see Raven and Roberts "British Cruisers of World War Two" Appendix 2 War Modifications)


1939 - 7x6" single mounts; 3x4" single HA; 2xsingle pom-pom; 4xquad 0.5"
8/42-4/43 refit - remove 1x6" and all single pom-pom & quad 0.5". Add 2xquad pom-pom with associated directors and 6xtwin 20mm
3-4/44 - remove catapult and add 6 single 20mm

That was a fairly typical RN cruiser light AA armament for the period. The smaller modified Dido, Spartan completed in Aug 1943 had 3 quad pom-pom (one in place of Q turret in the original Dido class) and 6 twin 20mm. The three slightly larger modified Fiji class completed Jan-July 1943 had 3 quad pom-pom (one in place of the triple 6" X turret of the original class) and 8-10 twin 20mm.

The three 4-inch HA are what I was missing! Those coupled with the two quad-40mm pompoms make an altogether more useful flak armament. I would be surprised if the 20mm Oerlikons were capable of being effectively director-fired, by radar or otherwise, while the main 6-inch guns are for shooting at ships and shore-targets only (and were always a little impractical as a hand-loaded deck-pivot gun)...

My understanding of the way the RN set up its AA guns that a quad-40mm (whether pompom or Bofors) was considered approximately comparable to a 4-inch in mounting weight, flak firepower and potential for centralised "director-firing" and radar-laying, and the two types were controlled together, whereas the lighter stuff like 20mm was just swung around by the gunner's bodyweight and aimed by eye.

Similarly, the director-fired AA of the Fiji class combines the three quad-40mm mountings with eight 4-inch HA secondaries, in two twin-mounts on each side; the Dido class tried to cheat, as their main armament of twin-mounted 5.25-inch guns was supposed to be dual-purpose, with a strong anti-aircraft emphasis, which removed the need for sided secondaries (in practice, less so; the two which got 4.5-inch main guns did better)...

Just by way of comparison a US Omaha class cruiser of similar age would have carried something like this in early 1943:-
10x6" (2x2 & 6x1 reduced from 12); 7x3"/50 singles; 2xtwin 40mm and 12x20mm singles (with 1x3" scheduled for replacement with a twin bofors when available).

Radar wise they carried a big SK warning radar (equivalent to Type 281) and a centimetric SG set for surface search (equivalent to Type 271/273). They also received 1/2 Mk 3 sets for gunnery fire control (equivalent of the RN Type 282/284/285 gunnery radars)

The Omaha is a very different design from a RN light cruiser of the pre-Treaty style, much more like an old-fashioned armoured cruiser - the most pertinent point here is that she's highsided with a long forecastle providing a full-width platform over the gangways, where there's extra room for seven AA guns in place of the Emerald's three; she was also proably less restricted in terms of topweight, because the USN was less cautious / more confident with margins of stability than the RN, and I suspect the hull was probably quite a bit deeper too...

 

[HP52]

One of the Skua's weaknesses was that it could only carry a 500lb bomb, which was inadequate against battleships, and provided less destructive power against (Japanese) carriers than the 1000lb bombs that were widely used by other dive bombers. Was the 500lb bomb the product of technical limitations, deliberate doctrinal choice for naval warfare (perhaps torpedoes are for killing ships?), the Air Ministry specification for a non-doctrinal reason, or something else?

I believe I have found the answer, somewhat in plain sight.

According to Neville Jones' The Beginnings of Strategic Air Power: A History of the British Bomber Force, 1923-1939, in July of 1932 the Chief of the Air Staff decided that no bomb larger than 500lbs would be produced. This was despite the fact that operational experience had shown the need for larger bombs, that Trenchard had stated in 1923 that 4000lb bombs would eventually be needed, and that a 1000lb bomb was in trials in 1930.

In 1935, a sub-committee of the Bombing Committee reaffirmed that no bombs over 500 lb should be produced.

Because the Skua was designed to Specification O.27/34, the 500lb limit was in effect, so there was no prospect of a larger bomb being introduced, even Blackburn had thought about going beyond the specification.

To make this even more tragic, early in 1939 the Air Staff called on Bomber Command to plan to attack enemy warships, and specifically to sink at least one German battleship. Beyond the Commander-in-Chief replying that he did not believe that his forces could hit enemy warships, the naval staff produced a paper "expressing the strongest doubts" that any kind of warship could be destroyed by the RAF's 500lb bombs. In other words, the Air Staff had simply ignored the possibility that the RAF might be called on to attack ships by bombing (presumably, they mentally assigned this role to torpedo bombers, which was not totally irrational, but would be impossible with land-based aircraft based in the UK). The contrast with the USAAC, which was obsessed with attacking battleships with high-altitude bombers, and with the IJN, is striking. This provides an example both powerful and subtle of the damage done to the Fleet Air Arm by making it part of the RAF.

tl;dr The RAF wasn't going to buy bombs bigger than 500lbs, so there was no point in designing a dive bomber to carry anything larger.


PS--The belief that more small bombs were better against industrial targets than a few large bombs also influenced the design of the Fairey Battle. Placing four 250lb bombs inside this wings as the primary armament make a thick wing necessary to accommodate them, regardless of the choice of wing profile for takeoff distance and range. The thick wing limited the maximum speed of the Battle after it had dropped its bombs. I cannot make a meaningful statement about the Battle's maximum speed and range if it had a thin wing and carried a single 1000lb (or 500lb) bomb externally.

PPS--The conversation around bombing ships was part of the "Oh, dear, the entire concept of the RAF was that our bomber forces would hit first, hit hard, and keep hitting until we win, but now we don't think that we can pull it off and we're afraid that if we do start bombing, the Luftwaffe will attack our airfields and annihilate Bomber Command, even though we don't think that there's any way that Bomber Command could attack Luftwaffe airfields with any effect, and the government is afraid that if we start bombing, the Germans will retaliate against London, and we agree that it's a risk and that the UK population might crack first and none of our thinking right now is internally consistent" period.

When 455 "Sqn Hampdens were called on to bomb the German fleet in the "Channel Dash", they were forced to bomb from low level, due weather and their bombs did not have the height to gain velocity and the bombs were reported as "bouncing off.

 

[HP52]

In 1937/38 Argus was converted to a Queen Bee carrier and was considered an auxiliary not a carrier.

In May 1939 the Admiralty looked forward to its carrier deployment in 1942 in the event of peace, war in Europe and war against Japan. By then it was anticipated that the first 6 armoured carriers would be in service (more were then planned). The plans for the old carriers were as follows:-

Argus & Eagle get no mention at all in any scenario. Argus probably due to her changed status. By 1942 Eagle's boilers were expected to need replaced so, given her other limitations, was probably not considered worthwhile giving a major refit to.

Peace
Furious, C&G & Hermes all in Reserve.

War
Furious was to be a training carrier in home waters.

C&G were to be active with air groups of only 24 aircraft each. Taken along with their proposed locations, it looks like they would be reduced to the trade protection role. European war = Kingston & Freetown. Far East war = Trincomalee and Singapore.

Hermes, with 12 aircraft would have been in the western Atlantic, either in Halifax or Kingston.

Having decided on one carrier, Indefatigable, for the 1939 Programme, at least one more was being planned for each of the 1940 & 1941 Programmes. Much discussion took place around the composition of each Programme.

I believe the Argus was laid down as a battleship (1918) but was converted to a Carrier. It went with PQ18 to fly Hurricanes off at max range to Murmansk (Vaenga/Severomorsk). It was the only carrier with lifts big enough to handle a ready to fly Hurricane, though one damaged its U/C on the hump at the bow designed to give aircraft a bit of extra lift on take off, It had to fly wheels down! They did give the Germans a jolt, when they came from nowhere to bomb Kirkennes on the way home. Several FAA aircraft were shot down and it only took 4 days toget the aircrew into Dulag Luft.

 

[MikeMeech]

I believe the Argus was laid down as a battleship (1918) but was converted to a Carrier. It went with PQ18 to fly Hurricanes off at max range to Murmansk (Vaenga/Severomorsk). It was the only carrier with lifts big enough to handle a ready to fly Hurricane, though one damaged its U/C on the hump at the bow designed to give aircraft a bit of extra lift on take off, It had to fly wheels down! They did give the Germans a jolt, when they came from nowhere to bomb Kirkennes on the way home. Several FAA aircraft were shot down and it only took 4 days toget the aircrew into Dulag Luft.

Hi
According to 'Aircraft Carriers of the World, 1914 to the Present' by Roger Chesneau, page 89, the ARGUS was originally laid down at Beardmore in early 1914 as the merchant ship CONTO ROSSO for the Lloyd Sabaudo Line. So has merchant ship origins rather than warship origins of some other early aircraft carriers.

Mike

 

[RCAFson]

I believe the Argus was laid down as a battleship (1918) but was converted to a Carrier. It went with PQ18 to fly Hurricanes off at max range to Murmansk (Vaenga/Severomorsk). It was the only carrier with lifts big enough to handle a ready to fly Hurricane, though one damaged its U/C on the hump at the bow designed to give aircraft a bit of extra lift on take off, It had to fly wheels down! They did give the Germans a jolt, when they came from nowhere to bomb Kirkennes on the way home. Several FAA aircraft were shot down and it only took 4 days toget the aircrew into Dulag Luft.

Argus's aircraft delivery to Russia actually preceded PQ18 by a year.

 

[EwenS]

I believe the Argus was laid down as a battleship (1918) but was converted to a Carrier. It went with PQ18 to fly Hurricanes off at max range to Murmansk (Vaenga/Severomorsk). It was the only carrier with lifts big enough to handle a ready to fly Hurricane, though one damaged its U/C on the hump at the bow designed to give aircraft a bit of extra lift on take off, It had to fly wheels down! They did give the Germans a jolt, when they came from nowhere to bomb Kirkennes on the way home. Several FAA aircraft were shot down and it only took 4 days toget the aircrew into Dulag Luft.

As well as the factual errors already point out, I think that you conflating a number of different events.

Firstly, as pointed out, Argus was converted from an Italian liner hull laid down in 1914, purchased by the Admiralty in Sept 1916 and completed as the first flush decked carrier in Sept 1918. It did not have a "hump" in its flight deck. And it was not the only carrier with lifts big enough to handle a fully assembled Hurricane. Both the lifts in Furious and at least the forward lift in Eagle were large enough and both these ships hosted Hurricanes & Sea Hurricanes during WW2.

The design of Indomitable was altered while she was being constructed to provide a forward lift large enough for a Hurricane and as well as flying off Hurricanes in the Indian Ocean, she operated Sea Hurricanes from her completion until late 1942. The US built escort carriers and some of the British built escort carriers also had lifts large enough to hande the Sea Hurricane. The last Sea Hurricanes were withdrawn from operational squadrons in Sept 1944 (825 & 835 on Vindex & Nairana respectively)

Operation Benedict comprising the 24 Hurricane IIb of two squadrons of 151 Wing (81 & 134) went to Russia on Argus, sailing at the end of Aug 1941 and being flown off on 7 Sept. 15 more arrived in crates on a merchantman shortly thereafter. After operating briefly and training Russian pilots on the type, the aircraft were handed over to the Russian Navy 78th IAP on 19 Oct and the personnel returned to the UK in Nov 1941. These were the first of approx 3,000 Hurricanes delivered to Russia.

80 years ago, September 1941 – Hurricanes to Russia (Operation Benedict) | RAF Memorial Flight Club

Header Image: Hawker Hurricane Mk IIBs of 151 Wing RAF at Vaenga, near Murmansk in the USSR, in September 1941. Eighty years ago, on 7th September 1941, as part of Operation Benedict, 24 Mk IIB Hurricanes of 81 and 134 Squadrons were flown off the aircraft carrier HMS Argus to land at the Soviet...

www.memorialflightclub.com

As for your reference to Kirkenes, which was in northern Norway about 500+ miles from Vaenga in Russia, I think you must be referring to the ill fated Operation EF on 30 July 1941. On that occasion aircraft from Victorious raided Kirkenes and those from Furious raided Petsamo. Furious carried a detachment from 880 squadron with 4 Sea Hurricanes for that operation.

Operation EF (1941) - Wikipedia

en.wikipedia.org

Now Furious was a carrier with a "hump" in its flight deck, and at various times ferried both Hurricanes and Spitfires seemingly with no problems caused by the "hump" in the flight deck. Can you please supply more details? There was one occasion during Operation Bellows in Aug 1942 (part of Operation Pedestal to Malta) when a Spitfire developed a fault on take off from Furious and landed back on the Indomitable, but that was due to a fuel problem.

Edit:- When ferrying Hurricanes it was a common practice to remove the outer wing panels for storage in the hangars of the carriers. That way more could be carried. They would then be reassembled immediately prior to being moved to the flight deck for take off. That was often done in batches as space permitted.

 

[elbmc1969]

The TBD ... It's unlikely that it could carry ASV radar.

Why?

 

[marathag]

Why?

Real Reason were losses after Midway, were pulled from front line service.
But there is no reason it couldn't have had something like USN AN/APS-4, had there been more in service.

or later AN/APS-4 had they still been in service in 1944, that was only 242 pounds

the AN/APS-6 airborne radar was a simplification of AN/APS-4 (ASH) suitable for single-seat fighters. It used a much smaller display, just 2 inches (5 cm) in diameter, which eliminated the need for a radar operator and served as a radar gunsight.
The parabolic antenna rotated at 1200 rotations per minute; in search mode, the antenna nodded while rotating to scan a spiral pattern coveringa 120 degree cone in front of the aircraft. In gunsight mode, the nodding was turned off and the antenna scanned a 15 degree cone in front of the aircraft. Search ranges could be set for 1, 5, 25, or 65 miles (1.6, 8, 40, and105 km), and the scope mode automatically changed for each range setting: The scope operated as a B scope at the two long range search settings or as an O scope at the two shorter search ranges. The scope also provided approximate altitude information from the sea return.

The prototype was developed in September 1943, but difficulties with the RF head head delayed production by Westinghouse until April 1944. The Pacific War Online Encyclopedia: APS-6 Airborne Radar

 

[RCAFson]

Why?

The TDB was grossly overweight by 1942 and the airframe wouldn't have been capable of carrying an ASV/ASB radar and a useful weapon load. Additionally it's short range and endurance would have been problematic.

 

[marathag]

The TDB was grossly overweight by 1942 and the airframe wouldn't have capable of carrying an ASV/ASB radar and a useful weapon load. Additionally it's short range and endurance would have been problematic.

AN/APS-3 was 300 pounds, and had twin scopes, as in the diagram above, for Pilot and operator. Used in other aircraft like TBF and PBY
300 pounds weight for install.
Where are you finding grossly overweight?

TBD had flaws, but that? Had 201 gallons of fuel. It needed the latest R-1830, for starters, and a trip to the wind tunnel for a TBD-2 before the war even started, and more than 130 built

6200 pounds empty was not out of line for an aircraft that size.

 

[EwenS]

But in 1942 centimetric AN/APS-3 (or ASD in USN parlance) and AN/APS-4 (ASH) were still in the future.

The radar introduced by the USN from late 1942 was the metric ASB (SCR-521). While lighter (152lb) and less capable, it needed Yagi aerials to transmit/receive which would have added drag to the airframe, slowing the TBD down even further. When fitted the effect was to reduce aircraft speed by 2-5 knots

The Pacific War Online Encyclopedia: ASV Airborne Radar

 

[tomo pauk]

IMO, The Devastator with a 1942-current R-1830 and a metric radar would've been just a fine aircraft for ASV patrols.

 

[Shortround6]

IMO, The Devastator with a 1942-current R-1830 and a metric radar would've been just a fine aircraft for ASV patrols.

Even a 1940 current R-1830.

 

[RCAFson]

AN/APS-3 was 300 pounds, and had twin scopes, as in the diagram above, for Pilot and operator. Used in other aircraft like TBF and PBY
300 pounds weight for install.
Where are you finding grossly overweight?

TBD had flaws, but that? Had 201 gallons of fuel. It needed the latest R-1830, for starters, and a trip to the wind tunnel for a TBD-2 before the war even started, and more than 130 built

6200 pounds empty was not out of line for an aircraft that size.

I'm looking at it's actual combat range and endurance in 1942. The TBD was being forced to TO at ~10400lb in 1942 with an 850hp engine...it was already problematic for TO even on the USN's large flight decks and fast carriers. If we add ASB radar, then we have to delete the torpedo to TO and if we find a target at night we can't attack it.

OK, we add a bigger engine (and even more weight) and then it will burn more fuel and range decreases even further. The airframe was lightly stressed and just not capable of handling more weight or higher performance; Just take a look at it's G and Vmax limits.