The cancelled Surrey Class, the last pre-war Washington Treaty heavy cruisers to be planned, had an interesting genesis.
Alongside the smaller B Type heavy cruiser (HMS York), the 1927-1928 Programme projected another A Type cruiser.
5-Turret County (2 layouts) 1927
In May 1927, during the Geneva Conference, the DNC began sketch designs on a 5-turret County. One had the fifth turret admidships and the other had it placed forwards. The midships layout restricted the arcs to 95 degrees on either beam and sacrificed habitability and protection. The forward arrangement would seriously affect the bridge with blast. The midships layout is drawn from the real sketch plans, the plans for the forward version have not seemingly survived. It has been drawn by John Roberts with C turret facing aft, but smurf and I feel there were several possible layouts and that Roberts' drawing was his own design. I've put the guns facing forward, which makes slightly more sense, but its possible other arrangements (raised C, back to back A & B etc.) were thought about.
Design X - early version 1927
The First Lord decided the cruiser should be a repeat Dorsetshire with increased protection. Armament on all is 4x2 8in, 4x1 4in, 2x8 pom-poms, 2x4 21in torpedo tubes and 2 aircraft (one Fairey IIIF spotter and one Fairey Flycatcher, although a 2-seater might have been carried - in any case the 8in turret could not support a catapult)
Smurf's research has seemingly uncovered a little known early version with a long 3.5in belt protecting the machinery spaces. On top was a 2in deck and 2in bulkheads to create a box. The magazines having 3in box protection (top and sides).
Design X 1927
The Design X most worked on and compared against the Design Y had 1,620 tons of armour. The machinery had a 5.75in thick belt covering the after boiler and fore turbine spaces to create a mini protected unit, the 2in bulkheads were still at the ends and some rearrangement was necessary to stop splinters entering the protected area. The deck was 2.25in thick and the magazines had 5.75in (top), 2.5in (lower) sides and 3in deck and bulkheads. Her machinery made 80,000hp for 32kts.
Design Y 1927
The DNC offered a better protected version of Design X which was slightly smaller, had a more compact 60,000hp machinery set for 30kts. The armour weighed 2,010 tons, essentially the extra weight allowing her smaller machinery spaces to be covered by the 9ft high 5.75in belt. The 3in deck would be assessed as proof against 8in shells to 20,000 yards and immune to 6in. To regain stability an extra foot of beam was added and her torpedoes were lowered.
The Controller actually preferred the faster Design X, seeing the extra armour of Y a poor compromise given X was faster and even if her unprotected machinery set was knocked out, the other could maintain 28kts. He felt X was better armoured than most Washington types. After much argument is was felt for trade protection duties, the loss of 2kts was not a handicap and a reasonable compromise for much better protection to her machinery. Ian Sturton argues in his Warship article that the Controller was correct, in WW2 poor speed was criticised in cruisers far more than lack of armour. In May 1928 the Admiralty approved the design. It would cost £126,500 more than Norfolk, £232,500 would be spent on armour. In November the legend was approved.
Design Y - later design with straight funnels and masts 1928
During the summer of 1928 the Director of the Senior Officers Technical Course discussed straight masts and funnels to deny the enemy easy judgement on course and speed. This was approved for all forthcoming cruisers despite potential smoke issues, although it was felt it would improve placing of catapults and boats. HMS Exeter's design was changed at the same time.
The probable appearance of the Surrey Class as they would have been built based on plans dated 1928.
An Exeter-style tower bridge was discussed and its possible these ships would have had them on completion, possibly a deck lower when the turret catapult was dropped. However, the 1928 plans show a bridge modelled on that of the later County series. The lower magazine side strake was upgraded from 2.5in to 3in during 1929.It is also possible that two fixed catapults fixed angled outboard (as shown in the 1929 Modified Surrey) would have been fitted during construction too. The drawing is in no way a complete rendition of how Surrey may have looked completed, but rather the state of play as she was planned to be laid down.
Two ships, HMS Northumberland and HMS Surrey, were to be built under the 1928-29 programme for completion by May 1932 (named 5 May 1929). They were never laid down due to budget cuts and a political focus by the Labour government on disarmament and all work was suspended on 23 August 1929 and both were officially cancelled on 14 January 1930.
Modified Surrey Design 1929
Two further ships were planned for the 1929-1930 Programme. The pom-poms were replaced by two quadruple 12.7mm Vickers machine-gun mounts. The Surrey design came out 100 tons under 10,000 tons so a small amount of additional armour was added; the boiler room fan chambers being up-armoured (4in side, 3in ends and 2in deck; Surrey had 2in side and 1in ends and deck); 2in on the deck above the transmission station (1in in Surrey), and 1in added to the turret ring supports (1in in Surrey). New endurance requirements were applied which meant 2,405 tons of oil was required, but the design capacity officially remained unchanged at 2,200 tons. The Board stamp was approved on 11 July 1929 but preparations for the 1930 London Conference proved an opportune moment for the Government and the Admiralty to stop the construction of expensive 8in cruisers.
There were a series of basic investigations by the DNC into further changes to the Surrey design. One involved replacing the 60,000shp machinery with 72,000hp to attain 30kts deep (Surrey 29kts). Early in 1929, Lillicrap looked at restoring the 80,000hp plant of the Counties for 31.5kts at standard displacement and 30.5kts deep. The machinery and longer armoured box would mean an increase of 430 tons but it was hoped 395 tons could be trimmed elsewhere and most ships completed below the target weight anyway.
Another study was to fit three triple turrets, the forward turrets fitted well but the narrow stern caused problems aft and extra beam would be required. The roller path for the triple was 22ft (twin was 18ft). Some oil capacity would be lost. A 3x3 8in ship with 80,000hp would save 144 tons, leaving 60 tons to perhaps add uniform deck armour over the machinery or add 0.5in on the belt. Further work in July 1929 using 120,000hp destroyer machinery came out 250 tons more than the 80,000hp County machinery or 50 tons more than the 60,000hp Surrey machinery. About 250 tons of oil would be lost, reducing range by 1,000nm (8,000nm at 12kts).
Special thanks is due to smurf for all his help, ideas and source materials. It had made a redux into an entire series of interesting ships.