G3 aircraft carriers for the Royal Navy

Anderman

Donor
The G3 was planned class of the battlecruiser for the Royal Navy post WW1. This ship were cancelled because of the Washington Naval Treaty.
The Treaty allowed the signatories to convert two existing or under construction capital ships into aircraft carries with a displacement of 33 000 tons.
For the USA this were two ships of the Lexington class (Lexington and Saratoga) for Japan Akagi and Kaga. The United Kingdom converted Courageous, Glorious and Furious.
So what if the United Kingdom converted two G3 battlecruisers?
I am not sure if the G3 were ever proper layed down which must be the case in this tl or no conversion can occure. Bringing the displacement down to 33 000 tons could be difficult because the G3 are larger the american or japanse ship with 48 000 tons standard compared to 43 000 tons standard for the Lexingtons .
How would this change the Royal Navy etc ?
 
The G3's were so early in construction that you would just design a purpose built carrier and construct that from scratch. Personally, I'd keep C&G as gunships (there was no need to scrap them and they didn't count as capital ships) for gunnery training and station flagships and lay down 2 27,000ton carriers in addition to the Nelson class BB. This will keep the ship building industry afloat with real work rather than just subsidies.
 
The UK misses out on a lot of experimentation.
There is a limit to how big a big carrier should be in the 40s and even more so in the 20s. While the US learnt a lot about big carriers the UK learnt a lot about a variety of carriers. In the end it is no accident that Arc Royal and Enterprise are basically interchangeable. Both sides knew roughly what they needed to do, short of some actual combat polishing. The difference is budgets and strategic situation.
 
Bringing the displacement down to 33 000 tons could be difficult because the G3 are larger the american or japanse ship with 48 000 tons standard compared to 43 000 tons standard for the Lexingtons .
This will be a real issue as Lex never got down to under 33,000t outside of USN declarations..... no way could a real G3 hull get under 33,0000t, the only way is simply to use 100t from the "existing keel" to make a new ship?
 
This will be a real issue as Lex never got down to under 33,000t outside of USN declarations..... no way could a real G3 hull get under 33,0000t, the only way is simply to use 100t from the "existing keel" to make a new ship?
AIUI the G3’s were all laid down shortly before the Washington talks. They were intended more as a bargaining chip in those talks as much as a prospective ship. Therefore I think 100 t of keel was about all that existed for at least some of them.
 
The UK misses out on a lot of experimentation.
They did have the basics well covered.
  • The acquisition, redesign and conversion of Ark Royal pre 1914 showed the RN could get things right from the get go.
  • A number of merchant conversions and combat experience from WW1.
  • Argus as a full deck conversion
  • Furious gives experience as a fast large carrier
  • Eagle to show greater speed was needed but the island was the way forward
  • Hermes to show that carriers needed to be designed and built bigger
  • Vindictive to show small conversions were not the way to go
C&G are merely slightly more capable Furious, heavily constrained to the hull they were built on. Exercises had shown that 8" guns were not necessary on carriers, purpose built 27,000 ton ships would have stood the RN in better stead than the conversion of C&G.
 
AIUI the G3’s were all laid down shortly before the Washington talks. They were intended more as a bargaining chip in those talks as much as a prospective ship. Therefore I think 100 t of keel was about all that existed for at least some of them.

I think we have similar understandings of the ephemeral nature of the G3s, but I thought at most 1 was laid down and it’s not even certain any were laid down because definitive documents or photographs of what the docks were doing in that extreme earliest stage are lacking.
 
G3 Design and Orders timeline
- from: Buxton, Ian; Johnston, Ian. The Battleship Builders Constructing and Arming British Capital Ships. Seaforth Publishing.

The Director of Naval Construction, Sir Eustace Tennyson d’Eyncourt, and his team of constructors began work bringing together a wealth of accumulated wartime operational experience as well as feedback from Hood which began trials early in 1920. Throughout 1920 and 1921, the DNC’s department developed a large number of designs most of which made a radical break from previous design conventions. With the G3 design complete, drawings were provided and a specification drawn up to enable the tendering process to begin.

August 1921. Provisional orders placed with Armstrong Whitworth and Vickers for the triple 16in main armament mountings and twin 6in mountings for the G3 battlecruisers. The 16in gun mountings were designed by Armstrong and the total requirement of twelve mountings plus three spares was split equally between the two firms. These complex and large mechanisms had to be ordered first to ensure they would be complete when the hulls were launched and ready for installation.

1 September. Invitations to tender sent to the following shipbuilders: Beardmore, Brown, Cammell Laird, Harland & Wolff, Vickers, Swan Hunter, Fairfield, Armstrong Whitworth. The shipbuilders were told that the tender should be based on materials and labour costs, that a fixed sum of £ 700,000 would cover establishment charges and profit and that a bonus for economical construction would be awarded. The bonus, a new tactic developed by the Admiralty to promote economy, was to be based on the average cost of all four ships on completion rather than the individual cost of each ship. Where the individual cost was below the average cost, the Admiralty agreed to apply a bonus of 30 per cent of the difference between the two prices. Completion of the ships was to be within thirty-six months after keel-laying. Contracts would be awarded only to employers who were members of the King’s National Roll Scheme. This scheme was established in 1915 to ensure that disabled ex-servicemen were not excluded from the job market.

8 October. Completed tenders were submitted to the Admiralty and the internal review of each tender, prices, technical strategies to be adopted etc., began.

24 October 1921. Hull and machinery contracts were provisionally awarded to the lowest bidders, John Brown, Fairfield and Swan Hunter. The machinery for the Swan Hunter ship was awarded to Parsons Marine Steam Turbine. Winning tenders. John Brown £ 3,879,000 Fairfield £ 3,900,000 Swan Hunter £ 3,977,175

31 October 1921. Notice given of drawing office work to be subdivided among the four contractors (the fourth had yet to be selected).

1 November. The fourth contract was awarded to Wm Beardmore & Co Ltd, at a tender price of £ 3,786,332 for the hull with machinery subcontracted to Vickers. All four ships were to be completed by 20 October 1924 (1 November for the Beardmore ship).

3 November. The Admiralty provided shipyards, starting with John Brown, with sufficient drawings including offsets to enable the hulls to be laid off.

11 November. A conference was held at the Admiralty attended by the shipbuilders and marine engineers to discuss engineering issues for the 160,000 shp turbine machinery installation.

12 November. Delegates from the leading naval powers gathered in Washington to begin negotiations intended to stop a new naval arms race developing.

14 November. The Admiralty provided shipbuilders with a list of the armour contractors for their ship in the table below.

16 November. The contracts for the ships were suspended until further notice pending the outcome of the Washington Conference.

22 November. Marine engineering personnel from the shipyards met the Engineer-in-Chief, Vice-Admiral Sir George Goodwin, to discuss machinery arrangements.

25 November. New machinery specifications issued. By the end of November, several new designs for battlecruisers of 35,000 tons, mounting 9 x 15in with 112,000 shp for 30 knots light on twin shafts, had been developed by the DNC in the expectation that if the G3s were not acceptable to the Conference then smaller battlecruisers might be required, given likely tonnage

6 December 1921. The Washington Conference concluded with an agreement that brought the existing naval construction plans of the major naval powers to an end. The Admiralty wrote to the shipbuilders stating that any expense incurred relative to the ship’s machinery was to be confined to turbine design arrangements, boiler design, feed arrangements, condenser evacuating arrangements and turbine drive for circulating pumps. Details were not to be considered and no expense was to be incurred with sub-contractors.

9 December. A further instruction from the Admiralty asked that drawing office and experimental work be carried out by John Brown in the following areas:
  1. Tests of electrically-welded deck plates.
  2. Full-sized test of a double bottom tank to determine the suitability of framing and frame spacing.
  3. Theoretical investigation into the strength of the main transverse and longitudinal bulkheads.
  4. Design work in connection with special fittings such as hatchway covers and similar arrangements to protect openings in the thick armour deck including the making of samples of such fittings for tests.
  5. Design of shaft brackets.
Fairfield was asked to continue with items 1 and 4 above and additionally to undertake the design of the stern post castings. Beardmore and Swan Hunter were asked to continue with item 1

13 February 1922. The Controller, Rear-Admiral Frederick Field, held a conference to consider the cancellation of the four battle-cruisers given the draft conclusions of the Washington Conference agreed on 10 February.

21 February 1922. The four shipbuilders were informed that it had definitely been decided that no further work was to be carried out on the hulls and machinery of the four battle-cruisers.

March 1922. Shipbuilders submitted expense claims. In the case of John Brown, this amounted to £ 32,000 covering all the work done by this firm on the G3 contract.

April 1922. Drawings supplied to shipbuilders were returned to the Admiralty.
 

Anderman

Donor
The G3's were so early in construction that you would just design a purpose built carrier and construct that from scratch. Personally, I'd keep C&G as gunships (there was no need to scrap them and they didn't count as capital ships) for gunnery training and station flagships and lay down 2 27,000ton carriers in addition to the Nelson class BB. This will keep the ship building industry afloat with real work rather than just subsidies.
It is very practical that the G3s were that early in construction so that made them nearly a purpose built carrier. :)
Are you sure that C&G didn´t count as capital ships ? They have guns larger than 8 inch and a displacement over 10 000 tons.
 
You'd have to disconnect a few of their boilers to get them below an acceptable maximum speed for training ships.
I could be wrong but I think they were basically ignored by the Washington treaty. I don't think they would even need to convert them. Though if they did not I am sure a later treaty would do something for them.
 
I could be wrong but I think they were basically ignored by the Washington treaty. I don't think they would even need to convert them. Though if they did not I am sure a later treaty would do something for them.
The issue is that one (F) was already or being converted so it might have been assumed or even unofficially agreed that the other two (C&G) were the RN conversions under the WNT?
 
The issue is that one (F) was already or being converted so it might have been assumed or even unofficially agreed that the other two (C&G) were the RN conversions under the WNT?
Maybe. I haven't seen anything about this, but it might be the case. However, Furious was given experimental status under the WNT while Courageous and Glorious were not. It seems strange that one would be designated as Experimental and open to replacement at any time but then be repeated in ships that were more permanent.
 
Maybe. I haven't seen anything about this, but it might be the case. However, Furious was given experimental status under the WNT while Courageous and Glorious were not. It seems strange that one would be designated as Experimental and open to replacement at any time but then be repeated in ships that were more permanent.
Is that not just an arbitrary date cap ie "all aircraft-carrier tonnage in existence or building on 12 November 1921 shall be considered experimental" is it not just that Furious is really the only fast & larger hull so converted and therefore scrapes in as the most useful?

Note that Furious is not really a fully converted CV like she was later, in 1921 she had separate take off and landing decks and was in the process of having them connected/replaced by a proper full flight deck and hangar like C&G had from the start of them being converted to CV in 1924.
 
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Maybe. I haven't seen anything about this, but it might be the case. However, Furious was given experimental status under the WNT while Courageous and Glorious were not. It seems strange that one would be designated as Experimental and open to replacement at any time but then be repeated in ships that were more permanent.
They need a cut off point for what's experimental or not and the signing of the Washington treaty is a logical choice. It's not as if C and G were converted to the same design as Furious, they were significantly improved by the addition of the island.
 

Anderman

Donor
The cut off date for experimental aircraft carriers was November 12 1921 as Article VIII

Article VIII​

The replacement of aircraft carriers shall be effected only as prescribed in Chapter II, Part 3, provided, however, that all aircraft carrier tonnage in existence or building on November 12, 1921, shall be considered experimental, and may be replaced, within the total tonnage limit prescribed in Article VII, without regard to its age.

 
They need a cut off point for what's experimental or not and the signing of the Washington treaty is a logical choice. It's not as if C and G were converted to the same design as Furious, they were significantly improved by the addition of the island.
It wouldn't have needed to be a date. They could have specified individual ships. But none of them were particularly worth saving, and no-one wanted to be the only one stuck with patch jobs when their rivals were building purpose built carriers. So they just said that everything made so far is experimental and the real rules only apply going forward.
 
It is very practical that the G3s were that early in construction so that made them nearly a purpose built carrier. :)
Are you sure that C&G didn´t count as capital ships ? They have guns larger than 8 inch and a displacement over 10 000 tons.

My understanding was that thyey were ignored/forgotten about....as had a number of the US armoured cruisers....nothing to stop them from being rebuilt at cruiser killers.
 
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