Shipbucket

I have never liked the Hawkins class with those horrible single hand worked 7.5". The actual 7.5" gun is a good one and should have been kept as the standard UK cruiser gun right through till the 6" cruisers of the Leander type came into production. The "keeping up with the Jones's" mentality meant that the 8" gun was chosen because everybody else had it. The weight saved by fitting the 7.5" in place of the 8" might have given a bit of extra armour that the 10,000 ton Treaty cruisers could have always done with a bit more of.

The Hawkins class was already pushing the treaty limits as far as tonnage was concerned. With a different layout to the main armament the class would have been exceptionally good value. The follow on County class would not have had to have to radical a change to do minor improvements over the original. New bridge structures and room for aircraft would have been made.

"The Hawkins class was already pushing the treaty limits as far as tonnage was concerned."
A proposed reconstruction with four twin 8in would have pushed them over the limits.
7 central pivot 7.5in weigh 7x46 = 322tons.
Four twin 7.5in weigh 4x 175 = 700tons which would also put the Hawkins over the 10,000ton limit.
We've been through this before: Dec 28th.
http://www.shipbucket.com/forums/viewto ... ss#p135505

The first try at a 10,000 ton cruiser design was based on Hawkins and was unsatisfactory (too slow).
The Counties' improvements over the Hawkins were not minor, but significant. Oil fired, flush deck giving stronger hull as well as four twin turrets. The 8in shell weight was 256lb compared to 200lb for the 7.5. That increase was thought worth having for greater armour penetration. The possible advantages of 7.5in over 8in guns were reviewed repeatedly during the 1920s and always rejected, though a simpler twin 8in turret trying for realistic rate of fire and not looking for 70degrees elevation might have been a good idea.

A good question that one "How fast is too slow?" For a cruiser being built at the end of WW1 and expected to be completed in the early 1920's such as the Hawkins, 29-31 knots would be more than fast enough. The 'E' designs aiming at 33 knots were already in the pipeline. The original mixed propulsion system was 60,000shp for 29-30 knots. The pure oil-fired propulsion system produced 70,000shp for 30-31 knots. The big difference between the Hawkins and later Counties is in the armouring. The Hawkins with its 3" belt and other armour was better protected than the Counties. It is of no use having guns with better penetration if a peashooter will go through the side of your ship. This was never put to the test of course as none of the counties or Hawkins types took part in any ship-to-ship engagements. The only time this may have happened is when Norfolk and Suffolk were at Denmark Strait they could have taken on the Eugen but were told to keep clear.

The 70 degree turrets were a mistake, second sight often helps. 45 degrees is enough to do the job. Get the 7.5" twin firing 6-8 rpm and that would be a good rate of fire compared to the 4-5 of the 8". It is like the 4" compared to the 4.5/4.7", the greater rate of fire outweighs the heavier shell.

My thought with the Hawkins drawings was to follow through with improvements to the basic design to see what could be made of it. It is worth remembering that the Hawkins was about the same size as the Edinburgh class of 15 years later. How would the Hawkins hull do with 10-12x6" (2x2-2x3 or 4x3) ?

I don't mind pushing a design to its limits, especially if it started out as a bit rubbishy.

Taking the basic design and making the standard improvements over their lifetimes. First drawing is the cumulative refits and modernisations that would have happened to the ship from completion through to the end of 1936. This includes the replacing of the single 4" with four twins, replacing the single 2 pounder with 4 quads, fitting of aircraft handling facilities. This suited the ship into WW2 when more refits and upgrades would take place. The second drawing is to reflect those additions made between 1939 through to mid/end of 1942. Remove the torpedoes and aircraft. Add a full radar suite and the first 40mm STAAG mountings, lots of 20mm singles.

@Krakatoa: A good question that one "How fast is too slow?
I was not very clear. "The first try at a 10,000 ton cruiser design was based on Hawkins and was unsatisfactory (too slow)." I did not mean that Hawkins was too slow, but that the initial attempt to design a 10,000ton Treaty cruiser (County) was based on Hawkins and was too slow, the initial Staff requirement being 33knots.

As to armour, a 3in belt will no more stop an 8in shell than would Counties' armour, though by the time WWII came, that had been increased with a 4.5in belt. Exeter with a 3 to 5in belt stood up to Graf Spee surprisingly well, but was sunk in the East Indies caught already damaged and alone apart from a two destroyer escort by a force of four Japanese cruisers.

Have you ever read "Second World War Cruisers: Was Armour Really Necessary?" D K Brown Warship 16, 121, 1992. A bit extreme, perhaps, but interesting. No navy got much armour on to 10,000tons + 8in guns in the 1920s. Goodall, DNC at the start of WWII, was quite confident that two Counties could deal with a Deutschland.

How would the Hawkins hull do with 10-12x6" (2x2-2x3 or 4x3) ?
There were three proposals to upgrade Hawkins from central pivot7.5in.
1. 1920s: fit three twin 8in. That would have put Hawkins a few hundred tons over the 10,000ton limit, because the hull aft was not deep enough to take a MkI twin 8in which would have had to be on a raised barbette. Compare Belfast with long trunk triple 6in instead of Southamptons short trunk triples. Also it was thought that RN finding four more 8in cruisers so quickly was contrary to the spirit of the Washington Treaty. 13 Counties were well under construction and the first on trials by 1927.
RN was always very fussy about keeping to the 10,000ton limit, which is why I pointed out that your Hawkins with turrets would have been over it.
2. 1930 after London Treaty limited numbers of RN 8in, four twin 6in were considered for Hawkins class but not adopted. Finance probably, plus faster ships (Leanders) wanted.
3. Hawkins class were due to be scrapped after 1936 but could be retained after 1936 with guns smaller than 8in. Effingham was reconstructed with 9 single 6in. 12 twin 5.25in turrets were ordered to equip Hawkins and Frobisher with six each, but the war came and 5.25 turrets were slow in production and needed elsewhere, with no dockyard capacity to convert old ships, so that too fell by the wayside.

Smurf, you come up with some wonderful information, a Hawkins with 12x5.25", I had never thought of that.

One of the reasons I like to keep the 7.5" is that it is smaller than the 8" and takes the pressure off the Admiralty and their strict adherence to Treaty regulations.

The 6" Hawkins I was thinking of was not a conversion but a new ship based on the Hawkins hull and a Southampton bridge and fittings.

I'm working on some drawings using the same Hawkins hull and the 8x7.5" layout with County fittings to see how they look.

As per my last post I give you a series of 'County' Class cruisers based on the hull and armament of the above Hawkins class cruisers.

An interesting what-if.

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Nice worked like the design and everything on it.

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With 4 more cruisers under construction, the London Treaty changed the format from 8" gunned ships to 6" gunned vessels. Rather than scrapping those ships under construction a new design was worked out with the new streamlined bridge structure and five twin 6" turrets.