The Centaur carrier fleet - a better fate...

[EwenS]

1942 Design Light Fleet Carrier - Wikipedia

en.m.wikipedia.org

Centaur-class aircraft carrier - Wikipedia

en.m.wikipedia.org

Let's say something different. I was thinking about cutting 4 Colossus and built more Centaur/Hermes. We can also cut the flexible deck trials (completely waste of money and time) and the Victorious refit - as proposed earlier in this thread. Britain would then have 3 Eagles, 2 Centaur and 2 Hermes, plus would built 4 (at least) additional Centaur/Hermes for export.

So, Argentina could get a Hermes carrier new. I was thinking about a air group of F-9F Cougar, Etendard IVM (later Super Etendard), Trackers and later A-4.

Other possible customers would be India, Canada and perhaps Brazil.

Grumman F-9 Cougar - Wikipedia

en.m.wikipedia.org

Seeing weights, stall speed and approach speed its I think that is possible for Hermes to launch the Cougar.

We have been over this before.

It means going back to 1943, by which time all 16 Colossus / Majestics have been ordered, if not all laid down. A sketch design for the Centaurs wasn't produced until mid 1943, let alone a detailed design (it was then altered post-war to produce the Centaur as we know it). If that decision process is not changed then the funding for 4 new Centaur class ships is not going to be available post war.

In 1943 they were considered controversial ships because their estimated completion dates were then in 1947/48 i.e too late for WW2. The compromise (there were those who would rather have seen all of them cancelled as they were ships for the next war not this one) was to allow construction of 4 to go ahead (laid down 1944/45) and leave the others suspended indefinitely. The argument in their favour at that point was that they would be able to operate the next generation of FAA aircraft being designed to 1943 Specifications, which a Colossus / Majestic couldn't operate and most of which never emerged in their intended form (Spearfish Sturgeon etc). And that is before jets had even been considered.

Only hindsight says the flexible deck trials might be considered a waste of money. It was a time of rapidly changing aircraft performance and it was believed at the time improvements in aircraft performance justified its investigation. Just how much money would you save? Not a lot in the overall scheme of things. By the way USN interest in the flexible deck concept continued until 1953, after British interest had ceased. So it can't have seemed such a wild and wacky idea to those at the time on either side of the pond.

https://www.usni.org/magazines/naval-history-magazine/2021/december/landing-aircraft-carrier-without-wheels

 

[Odysseus1980]

Ok then. But could the Hermes operate F-9F Cougar; just for curiosity

 

[BlackBat242]

Ok then. But could the Hermes operate F-9F Cougar; just for curiosity

Hermes AND Centaur both operated the Supermarine Scimitar - a larger and heavier jet that required stronger catapults and arresting gear than the Cougar - or the FJ-3/4 Fury, or the F4D Skyray.

In fact, I believe that the F11F Tiger MIGHT have been operable from Centaur - it was definitely operable from Hermes.

So yes, any steam catapult-equipped Centaur/Hermes class carrier could easily operate the F9F Cougar, the earlier F9F Panther, and the F2H Banshee.

The FJ-3 & FJ-4, the F4D, and probably the F11F Tiger could be operated as well.

Heck, since the Colossus/Majestics could, with steam catapults, operate A-4 Skyhawks (with a couple of restrictions) - the Centaur/Hermese CVs could easily do so with no restrictions.

 

[Odysseus1980]

Thanks!

 

[BlackBat242]

In particular, I have long wished for the RAN to have operated one (or two) Centaurs with steam catapults - and flown FJ-4s from them in the 1950s.

These would be in both the historic FJ-4B attack version and a new version with an air-intercept radar such as went in the F-86D or F-86K as well.

Then, in the 1960s A-4s & F-11s would replace the FJ-4s.

And yes, I just checked the SAC & flight instructions for the F11F Tiger and double-checked the catapults on Centaur... and Centaur could launch Tigers at max take-off weight safely with just the catapult end-speed and ship speed in the water, no external wind required.

 

[NOMISYRRUC]

I may have written this earlier in the thread.

Another way to give the Centaur class a better fate is for them to be completed sooner so the RN & British taxpayer gets several years of extra service out of them before they are made obsolete by the explosive growth in the size and weight of naval aircraft.

Although the British economy was in an appalling state in the late of 1940s would completing them by 1950 hurt the export drive to an appreciable degree? That is how many merchant ships (to rebuild the merchant navy and for export) had to be sacrificed to allow them to be completed in the late 1940s.

It might have saved money in the long term. IIRC (1) according to Brown their estimated cost when they were ordered was £2.8 million (compared to IIRC (2) £2.5 for a Colossus/Majestic). The first 3 ships cost about £10 million each. Hermes cost even more, but that was in part due to her completion to a modified design with more expensive equipment. Brown attributed the 4-fold increase in the cost of the first 3 ships to delays and inflation.

 

[H_K]

The first 3 ships cost about £10 million each. Hermes cost even more

How much did Victorious’s refit cost? Probably would have been cheaper to accelerate some of the Centaur builds and build them to Hermes standard.

 

[NOMISYRRUC]

How much did Victorious’s refit cost? Probably would have been cheaper to accelerate some of the Centaur builds and build them to Hermes standard.

From memory, most reference books say £20 million and some say £30 million, but they're probably typos for £20 million.

For a long time I wrote that Hermes cost £37.5 million because that's what Marriott wrote in his book about RN aircraft carriers, but she actually cost about £18 million so it was either a typo for £17.5 million or included the cost of her aircraft.

Do you meant that the money spent of rebuilding Victorious should have been spent on accelerating the Centaurs? That won't work because I suggested getting them completed before 1950 and the refit/rebuild of Victorious didn't begin until 1950.

Plus the long building times for the Centaur class weren't because the Government had to save money (building them in less time would have saved money if Brown was correct) it was because they available resources were being concentrated on the export drive.

On the other hand would completing them in the second half of the 1940s have damaged the British export drive to a measurable degree? Plus the resources expended on completing them 1950-59 IOTL (particularly 1950-54 by completing Albion, Bulwark & Centaur sooner) could be used for something else like the export drive.

Completing some of them to Hermes standard might not be possible as might already be too far advanced to make the required modifications to their hulls.

Also according to Marriott not much of the original Victorious was left when her refit was completed. As I've got the book out here are the relevant paragraphs verbatim.

The original plan had been merely to modernise the ship along conventional lines so that the ship would be able to operate up to 54 postwar aircraft, and the work was to have been completed by 1954. However, the development of the angled flight deck and steam catapults meant that the design had to be recast in order to include these, and this added to considerably to the cost and length of the programme. Another factor which acted to delay completion was a chronic shortage of skilled manpower at Portsmouth dockyard in the mid-1950s.

The actual rebuilding was a major engineering task which involved literally cutting the ship in two so that the hull could be lengthened by 30ft and beam increased by 8ft. The hull was stripped to he hangar deck and rebuilding of the flight deck already underway when it was decided that an angled deck would be incorporated; this was achieved by building a sponson structure 120ft long projecting 35ft out from the port side. Work on this was was proceeding when it was retrospectively decided to replace the old Admiralty pattern units, some of which had been damaged in an accidental fire. This involved undoing some of the work already carried out and meant further delay.

Below decks, virtually every compartment outside the machinery spaces was rebuilt, all wiring and piping was renewed, and new auxiliary machinery was installed. A remote machinery control room was provided and electrical generating capacity rose to 4,200k". On 19 March 1956 the ship was floated out of dry dock, but fitting out still took almost another two years.

The above, plus the new electronics (Type 984 radar, CDS, DPT, et al), steam catapults, new arrester gear, mirror landing sight and new guns indicates to me that all that remained of the original ship was the hull plating below the flight deck and the turbines.

Except that he's the only source I know of who says the hull was cut in two and that a 30ft section was added. Other people say that the flight deck was longer, but the between perpendiculars and waterline lengths were unchanged. Furthermore, the beam was increased by adding bulges.

And I think a more extensive rebuild than the minimum modernisation he writes about was intended from the start. I haven't checked my copies of Brown & Freidman but I think steam catapults were to have been fitted from the start, as was rebuilding everything above the hangar deck, rebuilding nearly everything below decks and the new guns. The major changes to the design after the refit began were the angled flight deck, Type 984 radar, CDS and DPT. Also (I repeat) that according to him the delay caused by the decision to replace the boilers was due to some of them being damaged by a fire, not lack of foresight by the project managers.

Finally, the increased size of naval aircraft meant that by the time she did re-enter service her aircraft capacity was only 28 (plus 8 helicopters) instead of the 54 planned originally. Except that the FAA might not have had the 18 extra aircraft to operate from her if the refit had been completed in 1954 and it would have only been for 4 years anyway.

 

[bobtdwarf]

https://www.scribd.com/document/136024395/Conway-Maritime-Press-Anatomy-of-the-Ship-Aircraft-Carrier-Victorious

Conways shows an increase of waterline length of 30 feet but no change in perpendicular length. Bulging the way it is described was to add width for decks above it so I would suspect external plating was new.

 

[NOMISYRRUC]

https://www.scribd.com/document/136024395/Conway-Maritime-Press-Anatomy-of-the-Ship-Aircraft-Carrier-Victorious

Conways shows an increase of waterline length of 30 feet but no change in perpendicular length. Bulging the way it is described was to add width for decks above it so I would suspect external plating was new.

That's peculiar because if the hull was lengthened by cutting the ship in half and attaching them to a new middle section the middle the perpendicular length would have been increased too. However, I'm not convinced that they did cut Victorious in half and attach them to a new middle section. For one thing if that's what they did do it would have made sense to insert a longer middle section.

For what it's worth the entry on the rebuilt Victorious in Conway's 1947-1995 say's the perpendicular length was 740ft compared to 673ft pp for the Illustrious class as built in Conway's 1922-1995. Neither gives a waterline length.

The perpendicular length of 740ft for the rebuilt Victorious in Conway's 1947-1995 and the waterline length for the rebuilt Victorious in the Anatomy of the Ship is 740ft. So there are some typos. I'm not sure which is the typo.

If I remember correctly the hull lengths for the rebuilt Victorious in early 1960s editions of Jane's are all longer than the ship as built, but then all except the flight deck's length return to their as build lengths by the middle 1960s. But its been a long day and I won't look at them now. For the same reason I won't look at my copy of Friedman to see what he says.

 

[bobtdwarf]

That's peculiar because if the hull was lengthened by cutting the ship in half and attaching them to a new middle section the middle the perpendicular length would have been increased too. However, I'm not convinced that they did cut Victorious in half and attach them to a new middle section. For one thing if that's what they did do it would have made sense to insert a longer middle section.

For what it's worth the entry on the rebuilt Victorious in Conway's 1947-1995 say's the perpendicular length was 740ft compared to 673ft pp for the Illustrious class as built in Conway's 1922-1995. Neither gives a waterline length.

The perpendicular length of 740ft for the rebuilt Victorious in Conway's 1947-1995 and the waterline length for the rebuilt Victorious in the Anatomy of the Ship is 740ft. So there are some typos. I'm not sure which is the typo.

If I remember correctly the hull lengths for the rebuilt Victorious in early 1960s editions of Jane's are all longer than the ship as built, but then all except the flight deck's length return to their as build lengths by the middle 1960s. But its been a long day and I won't look at them now. For the same reason I won't look at my copy of Friedman to see what he says.

definite weirdness going on.... also if you are going to cut her put the new section forward of center for longer bow cats.

Including a copy of a mock up I bashed up of an Implacable rebuild where I did that... hangar 590x62 or 64..

 

[Hood]

I tend to find Conway to be unreliable on details so I'd back going with other sources.

 

[H_K]

For what it's worth the entry on the rebuilt Victorious in Conway's 1947-1995 say's the perpendicular length was 740ft compared to 673ft pp for the Illustrious class as built in Conway's 1922-1995. Neither gives a waterline length.

The perpendicular length of 740ft for the rebuilt Victorious in Conway's 1947-1995 and the waterline length for the rebuilt Victorious in the Anatomy of the Ship is 740ft. So there are some typos. I'm not sure which is the typo.

Both incorrect. There was no change to Victorious's hull lines or hull sectional arrangement.
Here are Victorious's plans as rebuilt (1958) vs original plans from 1937, scaled to Shipbucket scale (2px=1ft).
Source: https://prints.rmg.co.uk/search?q=victorious&type=product

673ft pp (from front waterline to rudder stock)
710ft wl
~755ft oa (1937) increased to 775ft oa (1958) by adding a ~24ft flight deck overhang at the stern

One major change was the flight deck was raised by ~5ft (not sure if this was done to increase hangar height and/or to increase flight deck strength... I'd have to double check).

 

[EwenS]

Victorious was NOT stretched longitudinally during her reconstruction. That becomes clear from careful study of the drawings in the AOTS and the frame numbers before and after reconstruction.

But she was altered in cross section amidships by being bulged. Her original beam at the waterline was 95ft 9in. After reconstruction it was increased to 103ft 4in as per the AOTS book and Friedman. Again the changes become apparent from study of the drawings in AOTS especially in drawing B3.

Clear hangar height under the beams was increased from 16ft to 17ft 6in after reconstruction. The beams were increased to 8ft deep. The extra hull depth was also required to allow a full upper gallery deck to be worked into the ship immediately under the flight deck. A lot of this space was given over to crew accommodation.

 

[zen]

Confirm from Friedman and from a wonderful example of the Illustrators art I have. Obviously based on the real plans.

Victorious rebuild didn't stretch her, but they did widen to improve stability.

 

[H_K]

Victorious was NOT stretched longitudinally during her reconstruction. That becomes clear from careful study of the drawings in the AOTS and the frame numbers before and after reconstruction.

But she was altered in cross section amidships by being bulged. Her original beam at the waterline was 95ft 9in. After reconstruction it was increased to 103ft 4in as per the AOTS book and Friedman. Again the changes become apparent from study of the drawings in AOTS especially in drawing B3.

Clear hangar height under the beams was increased from 16ft to 17ft 6in after reconstruction. The beams were increased to 8ft deep. The extra hull depth was also required to allow a full upper gallery deck to be worked into the ship immediately under the flight deck. A lot of this space was given over to crew accommodation.

Thanks for confirming. Here's a comparison of HMS Victorious’ sectional views that shows both the bulges and the added gallery deck.

As rebuilt 1958 (left 2 sections) vs. 1937 plans (right 3 sections).

 

[BlackBat242]

definite weirdness going on.... also if you are going to cut her put the new section forward of center for longer bow cats.

Including a copy of a mock up I bashed up of an Implacable rebuild where I did that... hangar 590x62 or 64..

There is a major problem with your plans - the hangar floor after modernization was far too close to the waterline to allow deck-edge aircraft lifts - they would be regularly dipping into waves and allowing water into the hangar via the lift openings.

The RN considered 23' 6" to be the absolute minimum allowable for deck-edge lifts (they preferred 24'+), and Victorious' was 14'.

If you build the hangar floor one deck higher and eliminate the gallery deck you should just be able to fit deck-edge lifts, but not with the historic lower hangar floor and gallery deck between hangar and flight deck.


Hangar freeboards:

Victorious: 14' (post-modernization)
Centaur: 24' (see Hermes comment below)
Indomitable: 23' 6" (upper hangar)
Ark Royal & Eagle: upper hangar 30', lower hangar ~10' (thus Ark's early side lift only serving the upper hangar)
1952 carrier proposal: 24'

Clemenceau: 24'
de Gaulle: 23'

Cavour: 18' (light-moderate sea use only)

Essex: 25'
Midway 25'
CVN: 28'-30'
Wasp class: 34'

Hermes had issues with freeboard on her deck-edge aircraft lift... here is a comment from a former crewmember of Hermes (hermes82 on Navweaps):

Hermes' fwd lift was a deck edge side lift.
It was pretty dangerous in choppy weather nearly got washed over the side on at least 2 occasions, really thought I was a goner.
My mate was the lift driver at flight deck level he got submerged by one wave whilst we stuck a cab on it, you can imagine how wet we were.
The lift acted like a knife blade through the water when it was at hangar level damaged the cab as well.

 

[NOMISYRRUC]

The incorrect pp and wl hull lengths for the rebuilt Victorious are frequently quoted.

​

Jane's Fighting Ships.

- The first edition Jane's after her rebuilt that I have access to is 1960-61 it gives the wrong lengths.​

740ft pp​

781ft oa​

no waterline length was given.​

- Jane's 1961-62, 1962-63 and 1965-66 say the same.​

- I don't have access to copies of 1963-64 and 1964-65.​

- But 1966-67 and 1967-68 give the correct dimensions:​

673ft pp​

710ft wl​

781ft oa​

All it says in Jane's 1968-69 is.​

"Disposal of Victorious - The aircraft carrier Victorious was decommissioned on 13.05.68 pending disposal."​

​

The data table on Page 76 of Marriott's "Royal Navy Aircraft Carriers 1945-1990" doesn't say what the ship's waterline length was, but it does say that her waterline length was 740ft (incorrect) and that her overall length was 781ft (correct).

Friedman's data table on Page 305 gives the correct dimensions.

Legend, April 1950​

LBP 673ft 0in​

LWL 710ft 0in​

LOA 768ft 6in which in 1957 had increased to 778ft 3in​

Brown's "Rebuilding the Royal Navy" doesn't quote any hull lengths, but he does say.

It was also now realised that the boilers would only run until 1964 without a further extensive refit, so it was decided to reboiler the ship. This turned out to be a somewhat contorted and expensive exercise. The first difficulty was removing the old boilers, reconstruction having already reached the point where the armoured deck had been refitted, resulting in a considerable amount of the completed work being dismantled. The original idea had been to produce boilers of similar design to those originally fitted with existing auxiliary machinery and systems being retained, at an estimated cost of £250,000. The old boilers were removed and duly destroyed, but it was then found that modern boilers would be needed to meet the large intermittent steam requirements of the steam catapult. Provision of these new boilers plus some new auxiliary machinery resulted in the additional cost rising to £607,000. The Admiralty approved the scheme in December 1953, the figure quoted being £650,000 to provide a small margin.

And.

The final figure, £30 million, was far more expensive than ever envisaged; nevertheless the reconstruction was a success for a very useful modern carrier equipped for handling, operating, controlling and detecting modern jet aircraft was the result.

 

[NOMISYRRUC]

Part of Post 241.

Also here's a hypothetical enlarged Centaur, with a 66ft hull plug (i.e. 2 standard hull sections). Could have been an interesting what-if scenario if the RN had wanted to improve the Centaurs while still building them in the late 40s.

In a way it's a pity that Marriott was wrong about Victorious being stretched by 30ft by cutting her in two and adding a new centre section. That is, it would have given @H_K's proposal a large degree of plausibility, by showing that British industry had the capability to do it.

 

[JFC Fuller]

Brown's "Rebuilding the Royal Navy" doesn't quote any hull lengths, but he does say.

The final figure, £30 million, was far more expensive than ever envisaged; nevertheless the reconstruction was a success for a very useful modern carrier equipped for handling, operating, controlling and detecting modern jet aircraft was the result.

In have no idea why Brown says £30m, my guess is it’s a typo for the “nearly £20 million” reported to parliament in December 1959. The actual cost, as we’ve discussed before, was £19m.

 

[NOMISYRRUC]

In have no idea why Brown says £30m, my guess is it’s a typo for the “nearly £20 million” reported to parliament in December 1959. The actual cost, as we’ve discussed before, was £19m.

FWIW

• I've no idea either. I'll speculate that the extra £10 million may be the cost of her aircraft, but think your guess that it's a typo for £20 million is the real explanation.
• I knew the rest.
• Marriott says that the rebuilt Victorious cost £20 million.
• Another of Marriott's mistakes is that he says Hermes cost £37.5 million. That may be a typo for £17.5 million because (according to Hansard) her cost was approximately £18 million. (https://api.parliament.uk/historic-hansard/commons/1959/nov/25/hms-hermes).
• So the cost of building Hermes wasn't much less than the cost of rebuilding Victorious.

 

[bobtdwarf]

There is a major problem with your plans - the hangar floor after modernization was far too close to the waterline to allow deck-edge aircraft lifts - they would be regularly dipping into waves and allowing water into the hangar via the lift openings.

The RN considered 23' 6" to be the absolute minimum allowable for deck-edge lifts (they preferred 24'+), and Victorious' was 14'.

If you build the hangar floor one deck higher and eliminate the gallery deck you should just be able to fit deck-edge lifts, but not with the historic lower hangar floor and gallery deck between hangar and flight deck.


Hangar freeboards:

Victorious: 14' (post-modernization)
Centaur: 24' (see Hermes comment below)
Indomitable: 23' 6" (upper hangar)
Ark Royal & Eagle: upper hangar 30', lower hangar ~10' (thus Ark's early side lift only serving the upper hangar)
1952 carrier proposal: 24'

Clemenceau: 24'
de Gaulle: 23'

Cavour: 18' (light-moderate sea use only)

Essex: 25'
Midway 25'
CVN: 28'-30'
Wasp class: 34'

Hermes had issues with freeboard on her deck-edge aircraft lift... here is a comment from a former crewmember of Hermes (hermes82 on Navweaps):

agreed, mock up is a single hangar based on the top one.. Implacable was supposed to have a 16' bottom hangar but got a 14 footer... so rebuild raises new hangar floor by 2' so should be 24-25' from WL.

 

[Rule of cool]

I'm starting to form the opinion that the best course of action would be to finish the Centaurs as early as possible, with either axial flight decks or interim angled decks and have them get their wars in early; Korea and Suez. A war cruise each for A,B & C in Korea, Hermes in at Suez alongside whatever of A, B & C were available with Hermes and whatever of A, B & C were available to be Commando carriers from the late 50s. They cold all then have been seen as giving good service and retired honorably without lamenting that they didn't last forever, much like many of the Majestic class.

 

[Archibald]

Fact is that the Colossus / Majestic got long and rich careers, stretching as far as the 1990's. Only rivaled and eventually beaten by Hermes. India certainly squeezed every single drop of life out of its second-hand british carriers.
Bottom line: with the RN or not, it is a pity Albion, Bulwark and Centaur did not lasted as long as Hermes.

 

[Rule of cool]

Fact is that the Colossus / Majestic got long and rich careers, stretching as far as the 1990's. Only rivaled and eventually beaten by Hermes. India certainly squeezed every single drop of life out of its second-hand british carriers.
Bottom line: with the RN or not, it is a pity Albion, Bulwark and Centaur did not lasted as long as Hermes.

True, in secondary theatres and/or with 2nd (3rd?) tier powers. The RNs main adversary was the Soviet Union and the Centaurs were not suited to standing up to the Soviets from the 60s, that requires big fleet carriers.

 

[Rule of cool]

Was the massive increase in Victorious' "size" planned from the start, or was it a result of the 2nd tear-down and rebuild to a much more advanced spec?

 

[bobtdwarf]

Was the massive increase in Victorious' "size" planned from the start, or was it a result of the 2nd tear-down and rebuild to a much more advanced spec?

from the tear down and upgrading from a 35k pound deck to an improved Ark Royal 45k pound one.

 

[Rule of cool]

from the tear down and upgrading from a 35k pound deck to an improved Ark Royal 45k pound one.

Presumably the 2nd tear-down with the full angled deck, Type 984 etc would have increased the displacement even further.

 

[bobtdwarf]

Presumably the 2nd tear-down with the full angled deck, Type 984 etc would have increased the displacement even further.

it all flows from going to a 45k pound deck.. required bigger beams, so much bigger that a gallery deck is now on.... etc. Sticking to original axial, 35k deck and she is done mostly on budget in 3-ish years or so

 

[Polycrase]

Also here's a hypothetical enlarged Centaur, with a 66ft hull plug (i.e. 2 standard hull sections). Could have been an interesting what-if scenario if the RN had wanted to improve the Centaurs while still building them in the late 40s.

This would bring the Centaurs to "almost Clemenceau" size, allowing for a larger air group of ~24 fast jets.View attachment 744345

Is this an actual thing? because I'm interested in the source if that doesn't bother you, because I would be a bit interested in seeing the capacity of the non-jets in that thing had it been the original configuration, since the original had 42 aircraft if they are your day to day props, I want to see how much more could we cram in there if Centaur was designed that length

 

[H_K]

Is this an actual thing? because I'm interested in the source if that doesn't bother you, because I would be a bit interested in seeing the capacity of the non-jets in that thing had it been the original configuration, since the original had 42 aircraft if they are your day to day props, I want to see how much more could we cram in there if Centaur was designed that length

No - the Centaur hull extension is just my own hypothetical "what if".