Shipbucket

I'm currently working on the M2 and M3 battleship designs.

I have a query concerning the secondary 6in armament of the G-N series of battleships and battlecruisers.
I've had a brief chat about this with Smurf, and while I agree with his logical points, I thought I'd open this discussion up in the hope someone might know more.

My question is were turreted 6in secondaries always planned for these ships. We know G3 and N3 had them but did earlier designs? Many artist's impressions and fan art have depicted turrets copied from Nelson and G3 etc., but is this really accurate?
As Smurf points out, on the plans secondary armament is only marked out by circles on the deck plans and vertical rectangle blocks on the side plans. So they are placeholders. Smurf and me agree that given the protection of the ships that only armoured turrets would suffice. However the layouts have a variety of inconsistencies with that.
The H Designs seem to feature sided mounts mounted close to the side of the upper deck, my thought is that its feasible they might be casemates or single shielded mounts. The Ls look much the same. The rear superstructures of M2 and M3 feature a triangle section between each lower 6in mount that reaches to the side of the hull. This feature denies the 6in mounts 180 degree arcs and the circles representing the barbettes are fitted snugly into the corners where the extension meets the base of the triangle/superstructure side. There would be no room for a turret to traverse given the rear overhang of the turret. The G3 features clear cut-outs allowing turret traverse, the Ms do not. Also, the later G3 design featured its 6in guns inside large slit-like apertures in the superstructure. Where the guns in turrets inside these casemate like features as some kind of blast protection or where they shielded mounts?
I have never heard of planned shielded twin mounts for the battleships at this time, but is it possible that the switch to turrets was made during these design studies? I have not read anything to confirm or deny this theory, other than the turret armour was cut down in G3 to save weight.

Does anyone have any further info or opinions on this matter?

_________________
Hood's Worklist
English Electric Canberra FD
Interwar RN Capital Ships
Super-Darings
Never-Were British Aircraft

I would think that the timeline of each of the designs would make your job of mating secondaries to them a bit easier. It sounds like the earlier designs feature single shielded six inch in Admiral type slit arrangement. The later designs would have been to mate with the twin 6" introduced in 1926-27. Navweaps gives the design of the twin 6" as 'about' 1921. So any design after that date could easily have made allowances for the new weapons. Same with the 4.7", the first design was 1918, the one for G3 and Nelsons was dated 1925 with service entry in 1926.

The timeline for each of the designs would be your most significant tool.

Generally the letter designation increases with time.
You would assume these little circles and crosses would be next to cut-outs or recesses in the superstructures as with all sided turret layouts. This seems not to be the case. Either the sketch plans were not going to be chosen anyway so they didn't bother/ too lazy or a much more compact mount was hoped for. Enterprise's turrets are not exactly small. The fact so many of these mounts were next to the superstructure, with only a couple atop them, also makes me wonder, especially with the weird triangular projections, almost like forts.

_________________
Hood's Worklist
English Electric Canberra FD
Interwar RN Capital Ships
Super-Darings
Never-Were British Aircraft

Twin turrets for all the ships is the short answer.
Now the longer one. First, the nature of the drawings:
When a design is first proposed (sometimes in response to new formal Staff Requirements, sometimes simply to put forward ideas for developments of existing designs) the proposal may be accompanied by drawings which may be drawn by hand by a Constructor, or by a draftsman. Both are typically a few inches long, and may be approximately to scale, but they do no more than indicate the general layout of the proposed ship. The design is then developed by discussion in an Admiralty Committee, with a view to putting it forward for Board approval. During this stage sketch designs are prepared in more detail, usually to a scale of 1/16in to a foot (in 1918!). The resulting drawings (3 to 5ft long) depict a ship the positions of whose component parts are known accurately enough to be sure that the ship will float level. The drawing Hood posted on p2 of the "pre-Leander" Never Built thread is an example of a 1/16in =1ft drawing reproduced on a Warship page (and not very well scanned long ago by me!) It is however not necessary at that stage for the exact sizes, final positions and shapes of items like gun turrets to be known. Those may indeed change to an extent which requires these drawings at this "sketch design" stage to be redrawn. If and when the design is approved by the Board for construction, there follows a period of some months during which detailed "as-fitted" drawings (usual scale 1/4in = 1ft) are produced to govern the actions of the builders.

Secondly, in the particular case of these battleships, it appears that all (L,M,N and K,J,I,H and G to list them in order) progressed to the sketch design stage. At that stage at first glance the L designs had their secondary armament in positions which look like the Revenge class casemates [see the recent Never Built designs thread re the Royal Sovereign designs T1 and W1 whose original drawings are a few inches long in Tennyson d'Eyncourt's Notebook]. Others had their positions indicated by circles. Examination with a lens of the drawings reproduced across a single page of Warship No2 [article by NJM Campbell] including the L class, shows that all of them were to have "twin 6in BL guns", which is written alongside them though only crosses or circles appear on the diagrams. To the best of my knowledge, there was no twin 6in mount in existence. With such a mount being required for these ships, its development would be placed with the major gun makers (Armstrongs, Vickers) and design work would begin at the time of production of the first ship sketch designs, and could well (in fact did) take several years. Ship and gun design work went on in parallel, but it is clear that the post WWI capital ships were all intended to have twin 6in secondaries.
Only the G3 design advanced so far as to be ordered. For that design, "as-fitted" plans were prepared, showing the secondary armament layout in twin turrets. (Those plans also showed AA armament - 10-barrelled pompoms - guns and mountings never actually produced with more than eight barrels, only appearing for trials at the end of the 1920s)
For a parallel example, in the 1930's proposed destroyer armament (twin 4.7in mounts) showed great weight increases between the times when their installation was proposed and when building the ships actually started. It was hoped these would be ready for the 1936 ships, including a 62lb shell, but neither appeared until the J and L classes laid down from the end of 1937 with the heavier shell gun ready for only half the L class laid down in 1939. HMS Hereward tested the twin 4.7in mounting in January–March 1937.