Cruisers:
C Class Cruisers / Anti-aircraft ships:
The earlier C class were most likely to receive their conversions during that period 1936-38 and would have used a mixture of twin and single 4" (whatever was available at the time - the modern heavy and light cruisers were replacing their single 4" AA with twins during this period and that was probably where the guns for these conversions were coming from). With the Carolines layout I would have a twin forward, a pair of single 4" on either side of second funnel, another pair of single 4" in line at X position and a single 4" at Y position. One quad 2pd would replace the Q 6" position, a pair of 4x0.5" mg could be sited either side of the aft mast. I would not alter the superstructure at all. None of the AA conversions kept any torpedo tubes. The HACS (Mk1 at this age) would have been fitted on a tripod like Novice shows on his Caroline 2000, in a foretop that Novice has for the Coventry in 1936, the HACS aft would be fitted like the Coventry's. That would give the ships a respectable AA outfit and control system.
The Caledon sub class were used in WW2 with their original 6" armament and provided sterling service (in secondary roles). Converting the three ships of the class to AA cruisers would have livened up their WW2 careers. The variant shown below is as the surviving units were armed from 1942 onwards. Single and twin 20mm replacing the quad 0.5" mg's is the main change in armament.
Virtually each 'C' class AA conversion had its own template and the ships were very rarely converted to the same standard. So with 25 or so C's to play with you can have a fine old time designing different outfits for each ship.
The most common single 6" gun was used on all these types, Queen Elizabeth, Royal Sovereign, Arethusa, "B", "C", "D" and "E" cruiser classes, the mounting (from Navweaps) weighed in at 15,428 pounds. The twin 4" weighed, 4,500 pounds. The twin 4.5" UD mounting weighed, 6,304 pounds. Quad 2 pounder weighed 8.58 tons. So all of these mountings could be exchanged on a one-for-one basis and save weight.
D Class Cruisers / Anti-aircraft ships:
A few of the D class were to start being modernised as AA ships in a similar manner to the C class. The conversions were to commence in 1939. Only four of the twelve had commenced their conversions by the time war started. The most likely layout is number one with the quad 2 pounder in B position, while the real Delhi conversion and the twin 5" are possibilities if the US can be persuaded to assist. (twin 5"/38 weighed 75,250 complete. 6" singles, 17 tons.) The unmodernised ships went through the war with their single 6" and minor upgrades to the light AA as space and topweight permitted.
3 x E Class Cruisers:
The 'E' class were to be the fastest cruisers in the Royal Navy for over 10 years. The long lean hull and 80,000shp produced a speed of 33.5 knots. With three twin six inch turrets arranged one forward and two aft, the ships inspired the future Town class cruisers which had a different layout on a similar sized ship. Originally completed with single 4" and 2pdr AA guns, these were upgraded over time to twin 4", quad 2 pounder mountings, and 4 barrel 0.5"mg. With WW2 the ships added 20mm in single and twin mounts in place of the 0.5" mg's and the torpedoes and aircraft were removed while radar and other electronic equipment was added.
Frobisher Class Cruisers / Anti-aircraft ships
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. These are not conversions of the Hawkins, but a new design using the same hull.
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.
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.
Smurf said: there was even a proposal to arm Hawkins class with six twin 5.25". Though the proposal was not proceeded with, here is my take on what that might have looked like. The designs I drew went through many iterations before reaching the 4.5" version I have placed here in this thread. As per previous notes, I have not used the 5.25" at all in this thread so the 4.5" would be the gun of choice. The second drawing was done by BCRenown who postulated that one of the class could well have been sent to the US and converted under the Lend/Lease deal.
County Class Cruisers:
My new 'County' class cruisers use the same hull and armament as the Hawkins class, but improvements to layout and fittings make them a separate sub-class of their own. Any improvement that saved weight was put back into the design in improvements to the armour schemes. The ships were added to and subtracted from throughout their service lives. Aircraft fitted and upgraded then these facilities started being removed again in the 1940's. Radar and modern AA guns being added as refits came due.
G Class Cruisers:
The Admiralty was always conscious of the need for numbers of cruisers not just large cruisers. To this end instead of 13 County class, 3 are cancelled and replaced with six 5,000 ton light cruisers.
The 'G' class cruisers were based on the 1928-29 design for the return to the 6" cruiser. The basic design was altered and the latest models of superstructure were designed into the new ships. The Royal Navy had been introduced to the 5.5" gun with the two Greek cruisers taken over by the RN and commissioned as the Chester and Birkenhead. This had proved to be a very handy weapon and was fitted to many ships of all sorts of different classes. (This allows me to have an extra gun size in the armouries). Four twin light splinter proof turrets were fitted with these weapons. 4" AA guns provided the heavy AA while two 4 barrel 2 pounder pom poms were fitted as the light AA armament. Two banks of triple 21" torpedoes, a catapult and handling facilities for one aircraft.
With the completion of the last few Town class cruisers in 1938, the need for the smaller 'G' class as Patrol cruisers was obsolete. However the need for the new Anti-aircraft Cruiser type was of much more importance. The 'G' class were perfect for conversion. The first two were taken in hand in 1939, the second pair in 1940, and the final pair were converted in the US under Lend-Lease in 1941.
Neptune Class Cruiser:
With 4 more County class 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. These ships were an interim step while a new design was worked out for the new 6" cruisers that would populate and start replacing the oldest of the 'C' class cruisers that were fast approaching their 'use by' dates.
Town Class Cruisers:
The Town class cruiser were the evolution of the previous C, D, E, series of cruisers. The C and D had single 6", the E's (and Neptune) had twins. The Town class introduced the triple turret to RN cruisers with 3 mountings to be fitted on a hull approximately the same length as the E's. The beam was required to be wider to take the triple 6" mounting and went from 56 feet to 62 feet. Length was 563 feet. At 8,000 tons standard they were a very good return to the smaller cruiser that the RN needed. Eventually 16 of these vessels were completed between 1933 and 1938. From 1940 the new Colony class were introduced which were almost duplicates of these ships.
Andromeda Class Cruiser:
These are my replacement ships for the Arethusa class light cruisers. They are not as fast as the Arethusa type at 31 knots but have more armour and more staying power. The cross deck catapult was able to be fitted as the utilisation of the triple 6" required a broader hull. They are a cut down version of the previous Town class cruisers and showed what could be produced on 6,000 tons.
Dido Class Anti-Aircraft ships:
At 463 feet, these ships were big enough to be classed as cruisers, even though they were more over-large destroyers in their hull composition. A box of 2" armour around the magazines and propulsion systems was their one concession to armour. The twin 4.5" turrets only had splinter protection. The propulsion system produced 70,000shp for 34 knots, allowing their use with destroyers and part of their original role was to be as minelayers as well (with removable mine rails). The lack of cruisers meant that these ships were used regularly in that role. What they were purpose built for was as anti-aircraft escorts to the big new aircraft carriers.
Sirius Class cruisers:
While the RN was building small economical 6" cruisers, Japan and the US were building the Mogami and Brooklynn classes with fifteen guns each. Not to be outdone the Admiralty ordered the Sirius class with four quadruple six inch turrets for 16 guns. Originally to be a class of four, only two were completed, the materials for the other two were incorporated into the following Colony class. Arbitrarily classed as 'light' cruisers because they were armed with 6" guns, the ships were bigger than most of the RN's heavy cruisers. Because they were built outside Treaty limits the 10,000 ton limit was allowed to grow to 12,000 tons to enable a better armour scheme to be fitted. The belt armour went out to 5" and the deck armour to 3".
Leander Class Cruiser:
The Leander class cruisers came about from the rebuilding of the Nelson class battleships with dual purpose weapons. That work made 16 twin 6" turrets available for fitting on a new class of cruiser. Four ships were laid down based on the Dido class that was then in production. The hull was lengthened, but the ships retained the same power plant which in the Dido's made 34 knots, in the Leanders a respectable 32 knots was made. At 481x48 feet they were not large for cruisers. No thought was given to aircraft handling facilities on such a small cruiser. It was considered more important to have a decent AA battery, which with four twin 4" and four quad 2 pounder mountings they had plenty. 20mm cannons were added while the ships were still building.
Colony Class cruisers:
For class details, see page 12.
Niteroi Class Heavy Cruiser.
Once the Admiralty had time to take stock of what was under construction, what had been halted on outbreak of war, and what was still needed to be ordered, they found the Brazilian order for six H/I type of destroyers, and one heavy cruiser of an improved Sirius type. It may be hard to envision an improved Sirius with its 16x6", but Armstrong Whitworth had tried very hard. The Brazilian cruiser had been launched as the BNS Niteroi and was 75% complete at the outbreak of war when construction was suspended. At 640x72 feet the ship was not huge but the armament, armour and propulsion pushed it out to over 14,000 tons standard and 18,000 tons full load. The main armament of 12x8" gave it an advantage over any cruiser then in existence. Which was what it was supposed to do as the Argentinians had a cruiser under construction in Germany at the same time. Armour was also made to protect the ship against the same ship with 6" side armour and 3.5" of deck armour. Propulsion had not been stinted either with 120,000shp for 32 knots.
In early 1940 the Niteroi was purchased from the Brazilians and work on the ship recommenced. The ship being renamed Agamemnon. Completion was slated for late 1941, with new specifications for the electronics suite which the ship would not have originally been built with. The RN was not willing to give away its new toys to anybody. The main armament of 12x8" was a strange one for the RN as the rest of its heavy cruisers were armed with 7.5" guns. AW's had forseen that in the original specs by making the guns able to take US pattern 8" shells. The lesser armament had not been forgotten, 12x4" dual purpose guns with 16x2pd and 18x20mm AA weapons. British ships were still mounting torpedoes and two triple mountings of 21" were fitted.
Princess Royal Class Cruisers:
I have always liked Hoods Wesworld Super-CA HMS Princess Royal. It is a well balanced design for a large cruiser of the mid 40's and would compare well with its German and US counterparts. The design was started to outmatch the German Hipper class which had caused quite a stir when details were found out. My thought was to take the Wesworld version and bring it into our world as a ship designed in 1939-40, completed 1944-45, refitted in the 1950's and rebuilt in the 1960's. So the following 5 drawings reflect each of those time periods. Whether I have got the right stuff for the right time periods I am never sure of once I get past the end of WW2. Hood has been a great help with which Radar should go where, but all the mistakes are mine from ignorance.