G3 Cherry Trees

[perfectgeneral]

25 November 1921. 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

Having received instructions to draw up plans of a battlecruiser to meet the 35,000-ton requirement that seemed about to be agreed at the Washington Conference, the DNC produced two sketch designs, F2 and F3, in November 1921, both of which were armed with 15in guns. These were in either twin (F2) or triple, (F3) turrets, all forward as in the G3 design. Armour protection was generally reduced in comparison with the latter design. Speeds were 29.5 or 18 knots at deep displacement.

The final treaty allows two to be finished like this but the other two must be converted to aircraft carriers with no guns larger than 5.1in. Courageous and Glorious must be converted to large light cruisers, with 12 guns no larger than 6.1in, all others less than 5.1in. What are we looking at here? Could the C&G take on a AAA escort cruiser and dedicated fast tanker role alongside the F3 aircraft carriers? Were DNC plans at the time realistic given the difficulty attaining those design goals with KGV later? Could the cut down (by Washington) 35,000 ton hull (F3) offer a realistic aircraft carrier to match Lexi and Sara?

The eighteen new 15in/45 guns in six new, post Jutland turrets, could offer an upgrade path for the existing 15in/42 guns. When replacements ships A and B are due to be laid down on the Washington timetable (1931?) they might get the go ahead using old guns in the new style turrets to save some money.

http://shipbucket.com/drawings/5872/file

BB 1927 HMS Nelson

www.alternateuniversewarships.com

I do feel that having sacrificed the notion of horizontal (zero degree) firing ahead with the fore and middle turret they may as well go for a higher forecastle and improve the sea-keeping. All forward turrets caused problems with side blast in the bridge when firing aft. Broken windows and such. Hopefully the smaller 15inch gun reduces this problem, but nothing is perfect. Likely the 1930s follow on would have an aft turret.

 

[Peg Leg Pom]

The final treaty allows two to be finished like this but the other two must be converted to aircraft carriers with no guns larger than 5.1in. Courageous and Glorious must be converted to large light cruisers, with 12 guns no larger than 6.1in, all others less than 5.1in. What are we looking at here? Could the C&G take on a AAA cruiser and fast tanker role? Were DNC plans at the time realistic given the difficulty attaining those design goals with KGV later? Could the cut down (by Washington) 35,000 ton hull offer a realistic aircraft carrier to match Lexi and Sara?

Given how far along the G3's were at the time of the treaty (A few plates laid down on the slipways at most) you're effectively starting from scratch using the materials already ordered for the Battlecruisers. Now what would these two 35,000ton practically purpose built carriers be like?

 

[perfectgeneral]

Given how far along the G3's were at the time of the treaty (A few plates laid down on the slipways at most) you're effectively starting from scratch using the materials already ordered for the Battlecruisers. Now what would these two 35,000ton practically purpose built carriers be like?

I was hoping that the Saras would offer some indication. Could they differ all that much from the F3 hull and maintain the fiction that they are conversions of that class? It might look a bit Audacious or a larger Implacable with full height hangers? I'm not sure what they could have done with that much tonnage to play with. An armoured box seems unlikely. Adding plate to the hanger decks later more believable.

 

[EagleKeeper]

Why 5.1" guns? The only caliber limitation in WNT was anything over 8" was a capital ship.

 

[jsb]

Why 5.1" guns? The only caliber limitation in WNT was anything over 8" was a capital ship.

History and Technology - Washington Naval Limitation Treaty of 1922 - NavWeaps

www.navweaps.com

No CVs are limited gun & size numbers wise,

Article IX​

No aircraft-carrier exceeding 27,000 tons (27,432 metric tons) standard displacement shall be acquired by, or constructed by, for, or within the jurisdiction of, any of the Contracting Powers.
However, any of the Contracting Powers may, provided that its total tonnage allowance of aircraft-carriers is not thereby exceeded, build not more than two aircraft-carriers, each of a tonnage of not more than 33,000 tons (33,528 metric tons) standard displacement, and in order to effect economy any of the Contracting Powers may use for this purpose any two of their ships, whether constructed or in course of construction, which would otherwise be scrapped under the provisions of Article II. The armament of any aircraft-carriers exceeding 27,000 tons (27,432 metric tons) standard displacement shall be in accordance with the requirements of Article X, except that the total number of guns to be carried, in case any of such guns be of a calibre exceeding 6 inches (152 millimetres), except anti-aircraft guns and guns not exceeding 5 inches (127 millimetres), shall not exceed eight.

Article X​

No aircraft-carrier of any of the Contracting Powers shall carry a gun with a calibre in excess of 8 inches (203 millimetres). Without prejudice to the provisions of Article IX, if the armament carried includes guns exceeding 6 inches (152 millimetres) in calibre, the total number of guns carried, except anti-aircraft guns and guns not exceeding 5 inches (127 millimetres), shall not exceed ten. If, alternatively, the armament contains no guns exceeding 6 inches (152 millimetres) in calibre, the number of guns is not limited. In either case the number of anti-aircraft guns and of guns not exceeding 5 inches (127 millimetres) is not limited.

 

[Peg Leg Pom]

Just to illustrate how "advanced" construction of the G3's were when they were suspended for the Washington Treaty negotiations that led to their cancellation. Any "conversion" is going to be a clean sheet design.

(This is actually USS United States CV58 construction of which lasted as long as the G3's. The keel was laid and she was almost immediately cancelled )