9.2" HMS Belfast

[YYJ]

If the Royal Navy decided that it would be useful to have some 9.2” cruisers, now that the LNT was kaput and what with the War, would it be possible to fit out HMS Belfast with 4 x 2 9.2” guns? Such a refit would make good use of the time between January 1940 and November 1942 she spent being rebuild from her mine damage.

As near as I can tell, only 6 twin 9.2” turrets were build for the Royal Navy, for the Minotaur Class armoured cruisers, and 2 of them went to the bottom of the North Sea in Defence. I doubt these turrets would swap over to a Treaty cruiser. For one thing they had 7 inches of armour, which would probably make them too damn heavy. And I imagine those turrets would have been cut apart to show that Britain was observing the LNT. So new mounts would have to be designed and build, although some designs might be sitting in a filing cabinet in the Admiralty.

Existing ships as candidates for this conversion I could see would be the 2 Edinburgh class light cruisers and the full size County Class heavy cruisers. Perhaps it would be possible to shoehorn 2 9.2” guns into an 8” turret, but again I doubt it. Up gunning heavy cruisers would be going in the opposite direction from the Royal Navy’s decision to stop building 8” cruisers and that 6” was the best cruiser gun. But a 32 knot 8 x 9.2” cruiser would make a great cheap Panzerschiff hunter. And if Belfast and Norfolk had brought 16 radar directed 9.2” guns to the Battle of North Cape, they could have probably have taken Scharnhorst apart without needing the Duke of York.

 

[WaterproofPotatoes]

Would you be proposing something like a one-off "cruiser with her great aunt's teeth" (like HMS Vanguard using the 15" guns from HM Ships Courageous and Glorious)?

 

[Schlock]

You'd probably need at least a 15,000 ton hull for a balanced design at the bare minimum.

 

[YYJ]

Would you be proposing something like a one-off "cruiser with her great aunt's teeth" (like HMS Vanguard using the 15" guns from HM Ships Courageous and Glorious)?

Maybe, if that was the easiest path. 9.2” guns stopped being naval guns in the RN at the end of WW1, but they were still used as coast defence guns, so maybe they were still being made between the wars or later. 3 were guarding my town until the ‘50s.

I just got thinking about my thread about a crazy rebuild of Agincourt that drifted into a possible useful rebuild with 9.2” guns. But it seemed to me like Agincourt was too much ship for that battery. I was wondering if Treaty Cruisers would work, or if they would be not enough ship

 

[WaterproofPotatoes]

Maybe, if that was the easiest path. 9.2” guns stopped being naval guns in the RN at the end of WW1, but they were still used as coast defence guns, so maybe they were still being made between the wars or later. 3 were guarding my town until the ‘50s.

I just got thinking about my thread about a crazy rebuild of Agincourt that drifted into a possible useful rebuild with 9.2” guns. But it seemed to me like Agincourt was too much ship for that battery. I was wondering if Treaty Cruisers would work, or if they would be not enough ship

Victoria, BC if I remember my IATA codes correctly

The other big problem is that she would be the only ship in the RN using 9.2". Where is all that ammo coming from?

 

[YYJ]

The other big problem is that she would be the only ship in the RN using 9.2". Where is all that ammo coming from?

If multiple ships were converted, then there would be more than one! I figure that since the caliber was still used by coastal artillery the ammunition would still be available. It would be easier if the ship or ships in question operate out of a single port. But they could get replenished at Gibraltar, or Esquimalt, or any other RN base defended by 9.2" coastal artillery. In the same way that ATLs that have Tiger or Iron Duke soldiering on have all the left over 13.5" shells from WWI that are being used for railroad guns. HMS Hawkins and HMS Frobisher went to WW2 with 7.5" guns, which was a pretty orphan caliber by that point.

Yes, Victoria is correct.

 

[StevoJH]

They were still in service as coastal defence batteries, so the ammunition was available.

 

[Paul_Sussex]

Funnily, I was thinking about this a couple of days ago. Weren't the eight twin turrets from the Lord Nelsons also in store? According to Wikipedia "After the scrapping of these ships, these guns and mountings were retained in storage". But didn't they have a fairly short range, even compared to the BL 6 inch?

 

[steamboy]

The 9.2-inch gun was a common coast defence weapon for the UK and Empire and there's probably enough barrels and shells lying around. The UK was apparently looking at a kind of 'super cruiser' to be armed with 9 x 9.2-inch guns at some point in the war, but this was canned as they would have been very big, expensive ships and would have been little cheaper than making a full fledged battleship.

Study 1 (9.2in gun/20,000t): The design was developed in some detail. 39 The ship would be about the size of a carrier; DNC suggested starting with 132,000shp. DNO provided data on a quadruple 9.2in turret. The belt armour would resist 10in shells 40 ° from normal at 16,000yds; the deck was expected to resist 10in shells and also a 1,000lb AP bomb dropped from 8,000ft. DNC suggested a short forecastle design with a hangar and the usual alternating engine and boiler rooms, the machinery box being pushed well aft (as in Belfast). A cross-section showed a 16ft 6in deep belt extending 11ft 6in above the waterline, with an internal deck below the armour deck but well above water, and a side protective system inboard of the belt. Hull depth would have been 35ft 6in. The belt would have been closed by 6in bulkheads. As in recent much smaller cruisers, the belt armour, rather than armour boxes, would have protected the magazines. The 20,000-ton hull actually proved somewhat small, so John tried a 23,700-tonner as well. 40 To get back down, John tried triple 9.2in guns, but found he did not have enough machinery weight to make 33kts. He had to reduce armour. 41 By early February 1938 this design was being called an armoured cruiser.

Study 2 (8in/9.2in 21,750t): DNC next asked what could be done with nine 8in guns (Design A), or with nine 9.2in (Design B). Speed was set at 33kts and endurance at 10,000nm at 15kts. Other armament was six twin 4.5in, four octuple and two single pompoms, and twelve torpedo tubes. Armour should defeat the ship’s own guns at 90 ° inclination (worst case) between 8,000 and 25,000yds (with an inch less over machinery). The deck over the magazines should defeat a 500lb SAP bomb dropped from 10,000ft (over machinery, a 500lb dive bomb); and underwater protection should, as before, defeat a 750lb charge. For the 9.2in gun, this was more than had been asked for before: 10 ½ in C over magazines and 9 ½ in over machinery, with a 3 ½ in deck over magazines and 2 ½ in over machinery. 42 For 8in shellfire it was quite heavy, too: 9in (8in) belt and 3 ½ in (2 ½ in deck). Deck armour was the same in both cases because it was determined by the bombs, not the shells. This was the sort of protection the US Navy later provided in the Alaska class, not even approached in any conventional cruiser. A sketch showed a ship with a waterline beam of 84ft, bulged underwater to 88ft, so that the battleship-style underwater (side) protective system could be 10ft deep. DNC received the report of this pair of designs on 28 February and in turn reported to Controller on 4 March. The ship with nine 8in guns was expected to displace 21,750 tons and to cost £ 5.5 million.

Study 1 (9.2in / 15,000t): Once war broke out, there was no longer any point in a 10,000-ton limit, and Winston Churchill, back as First Lord of the Admiralty, pushed for a powerful ship. John was assigned to develop a new 14,000-15,000-ton cruiser armed with 9.2in guns and protected against 8in shellfire, with a good radius of action, higher speed than the German 8in cruisers (say 33/ 34kts), six twin 4.5in anti-aircraft guns, and four quadruple pompoms; she would have no torpedo tubes. The ship would carry the usual two aircraft and one catapult, and she would be protected against aircraft torpedoes. 49 Given the earlier studies, John chose a 7in belt and 2in deck (3in if possible), considering a 9in belt excessive. Cruisers would generally fight at something other than 90 ° inclination. At 90 ° it took 9in to keep out 8in fire at 8,000yds, but 7in would be enough at 8,800yds at a reasonable 60 ° inclination. The ship quickly grew back to what John had been sketching early in 1938, about 21,500 tons and 700ft long.

This is a seriously large ship, more akin to a Battlecruiser than a heavy cruiser and would have been the British equivalent of a Alaska type ship. But to fit such guns on a Belfast might be a bit of an ask, you'd have to redesign the turrets and barbettes and it might well be easier to make a new ship rathe than alter this. Also the UK preferred faster firing 6-inch guns as a matter of doctrine and i'd say that the 9.2's would probably fire too slowly for anti-cruiser work without a serious redesign. And at the time, there wasn't the dockyard space for such a vessel and if one was laid down she'd probably not be ready any time before mid-late 42 when the RN needed swarms of destroyers and as many Colony class cruisers as they could fart out.

I dunno if the UK was planning on re-using 9.2's from the Great War because they were not that great a gun, they were high velocity but not that accurate. Also these old guns would have weighed a lot so I'd assume that the UK would have gone and made a newer version of the gun instead of using older coast defence guns.

 

[YYJ]

Funnily, I was thinking about this a couple of days ago. Weren't the eight twin turrets from the Lord Nelsons also in store? According to Wikipedia "After the scrapping of these ships, these guns and mountings were retained in storage". But didn't they have a fairly short range, even compared to the BL 6 inch?

Well blow me down, the Lord Nelsons used twin 9.2" turrets as well. So that does give another 8 surplus twin turrets. The Lord Nelson turrets look the same as the twin 9.2" turrets form the Minotaur class, and the ships were build at the same time. Both ships turrets are listed as having 7"-8" of armour, so I am guessing they are identical.
I think the range you are talking about has to do with elevation. The Minotaur's main armament range is listed in Wiki as 16,000 yards with max elevation of 15 degrees. Later versions of the same gun in coastal defence mountings have range listed as 29,500 yards at 30 degrees and 36,700 yards at 35 degrees.

 

[steamboy]

Problem is that the turrets are totally incompatible with the changes in flash protection etc, so you'd have a Vanguard esque issue of having to re-work the interior of the turret and all the gubbins below it. Also the armours old, you're talking nearly 40 year old metal and they are heavy mounts. They would put a lot of strain on the hull and its not just a case of a 1-1 swap. Also I doubt the turrets and mountings themselves would have survived, the guns yes, many were put in storage or used as coast defence weapons, but the turrets themselves would have been scrapped.

 

[Not James Stockdale]

Single 9.2" turrets that went on British monitors, armoured cruisers, and pre-dreadnoughts weighed in the 110 to 130 ton range without armor. You would probably double that weight to accommodate a second gun, so you're already at least 60 tons heavier than the Town class's 180 ton triple turrets, and you don't have any armor, which would probably require 40 to 60 tons. A better option would be the twin 8" mounts of the County class would run up to 220 tons and would probably actually fit inside the ship.

 

[Riain]

dunno if the UK was planning on re-using 9.2's from the Great War because they were not that great a gun, they were high velocity but not that accurate. Also these old guns would have weighed a lot so I'd assume that the UK would have gone and made a newer version of the gun instead of using older coast defence guns.

I agree, they were a very old design and not a 'classic' like the 15". I don't think that the RN can repeat what they were able to do with the 15" with any old gun.

A better bet might be the twin 8" turrets of the county class cruisers.

 

[steamboy]

You could probably reduce the weight of the 8-inch guns and their mounting as they needed hella tall barbettes because of the requirement for high angle AA fire. Eliminate that and you reduce the height and weight of the mounting.

 

[alspug]

The British twin 8 inch used on the Counties was badly conceived due to the need for 70 degree AA fire. Any design for a 9.2 inch cruiser would need to be built from the ground up as such . It is known for example that the Japanese 6 in cruisers had been designed from the beginning to take a twin 8 inch mount . I would guess they designed the 8 inch and then worked out how to make a 6 inch triple fit . Doing it the other way would be more difficult . 8 inch barrel weighed 15 ton however the mounting for a twin was 220 ton . From this it is easy to see that the gun weight to mounting weight is more dependent on protection , flash tightness and traverse/elevation limits and speeds . If the benefit of knowledge with regards to WW2 and after is used then any Cruiser envisioned should be sufficiently armed to kill any peer opponent and sufficiently armoured to defend the same . AON armour is expected . Secondary mounts will be at a minimum 3 twin mounts per side of either 4 or 4.5 . Tertiary mounts can pre war be based on quad Pom Poms again 3 per side . Then throw some twin or quad 50 cal around like you got them cheap . The Pom Pom mounts can be changed to quad US pattern or later twin STAG mounts of 40 mm bofors . Do not expect any change out of 20,000 tons . They would make a great Carrier escort for the Cold War as nothing the soviets had until SSM in the late 60's early 70's would scratch them . As far as dinosaurs go they would be great . Better to spend the money on proper aircraft for the Carriers .

 

[StevoJH]

On 20,000 tons they would probably get the twin 5.25” turrets as secondaries, same as what the King George V class and HMS Vanguard got.

 

[Deleted member 94680]

What’s the purpose of this ship? Cruiser killer? Dedicated fire support vessel?

 

[steamboy]

On 20,000 tons they would probably get the twin 5.25” turrets as secondaries, same as what the King George V class and HMS Vanguard got.

At the time there was a lack of mountings for the guns (its why some Dido's completed with 4.5 inch guns) and wasn't enough guns or mountings to go around, so they'd probably go with the far more available 4.5's.

 

[jsb]

What’s the purpose of this ship? Cruiser killer? Dedicated fire support vessel?

British equivalent of a Alaska type ship.

Why does the RN want this bad idea?

For the same price you can build,
- more 8" or 6" cruisers that will do the job just as well and be in more places at once....
- not many less 15" BBs that can actually fight capital ships...

Why would RN want to destabilize the treaties even after 2LNT? Any ship started after 39 is never going to be ready in time to be worthwhile...

 

[steamboy]

Oh indeed! She's grossly inefficient and is a ship looking for a role *cough*Alaska class*cough* I'm just answering the OP