In mid-August ACNS announced a Sea Lords meeting about a month
hence to discuss the design of what was now called a 35,000-ton
battlecruiser. He asked for a 27-knot ship, the reduction buying either
protection or gun power. Design 14F (9 September) had the same three
quadruple turrets as 14C, but it was shorter (700ft pp) with less power
(80,000 SHP for 26 knots; 2375 tons of machinery). A lighter hull and
lighter machinery bought 13in (6in deck) over magazines and 12in (4in)
over machinery. At 90° inclination the belt over magazines should be
immune to the 14in 2900ft/sec gun outside 15,000 yds (at a 70° angle,
outside 13,500 yds). The belt over machinery would be immune at
17,000yds (15,500 yds at 70°). Deck armour over magazines could not be
penetrated at all; over machinery it could be penetrated outside 36,000 yds.
The decks over the magazines could not be penetrated by a 500lb SAP
bomb. A 1000lb AP bomb would have to be dropped from 15,000ft, at
which altitude hits were most unlikely. The same bomb would penetrate
the deck over machinery from 7000ft and the SAP bomb would penetrate
the machinery deck only from above 12,000ft – again, an altitude making
hits unlikely.
At about the same time (3 September) DTD pointed out that the choice
of main battery calibre was now urgent. By this time the Germans had
announced that their new ships would have 15in guns, so ACNS added
that weapon to the mix (Design 16A was rejected). To ACNS the choices
were a 30-knot ship, slightly better protected than 14D, mounting nine 15in
(three triples); a 27-knot ship, with full (battleship) protection as in 14E,
mounting nine 15in (three triples); and a 27-knot ship, better protected than
14E, mounting eight 16in (two triple, one twin mounting). Although there
was no interest in reviving the Nelson design, it was necessary to ask what
armament a modernised Nelson might mount. Concentrating the turrets
forward would save about 800 tons in a 35,000-ton battlecruiser. If that
were true, further possibilities arose: (a) a 30-knot ship protected like 14D,
with nine 15in; (b) a 30-knot ship with eight 16in guns (two triple, one
twin) protected slightly better than 14E; (c) a 27-knot ship with eight 16in
and battleship protection (as in 14D); and (d) a 27-knot ship with nine
16in, slightly better protected than 14E. ACNS asked Controller to produce
appropriate design figures.
King George V Cover No. 4 Folio 58A/58B is a set of statements about the logic of
the new battleship designs provided to CNS in June 1939. They claim that a sketch
design with a Nelson arrangement was worked out but found to be no more
economical in weight than the divided battery adopted, owing to the increased length
of machinery space. Moreover, ‘the possible introduction of bombs and torpedoes
exploding under the bottom made it desirable that the main armament should not be
concentrated as in Nelson. This last argument does not seem to appear in the Cover
detailing the different designs. The reference is to ‘B’ bombs and to non-contact
(magneticfuzed) torpedoes.
Given all the previous work, DNC could offer alternatives without
preparing detailed sketch designs: (a) 15A: a 30-knot ship protected like
14E (but with deck over machinery reduced to 4½in), armed with nine
15in; (b) 15B: a 27-knot ship armed with nine 15in, protected like 14D, but
with deck over magazines reduced to 6in; and (c) 16B: a 27-knot ship
armed with eight 16in, protected like 14E. In 16B about 600 more tons
were available, so magazine side armour was increased to 14in, machinery
side to 13in and magazine deck to 6in. Although grouping the main battery
together had saved considerable weight in Nelson, that arrangement was
no longer likely to work given the considerable space the new ship would
require for a dual-purpose secondary battery and for her aircraft. Nor was
it likely that the machinery could be accommodated in the narrow after end
of a fast ship.
Given the German announcement, on 20 September 1935 a Sea Lords
conference decided that the first two post-treaty ships should be armed
with nine 15in guns. This design was to be investigated in detail as 15C.
King George V Cover No. 1, Folio 50; there is no reference to the conference
elsewhere in the Cover.
It had more powerful machinery (108,000 SHP for 28.5 knots). It soon
turned out that the Americans would accept a 14in gun limit, a great prize
from the British point of view – provided the Japanese would go along. A
few days later (10 October) First Sea Lord (Chatfield) wrote that the 15in
designs were not well enough balanced (i.e., both fast and sufficiently
protected). That was probably a convenient way to live with a decision
forced by the treaty conference. The 15in design was dropped.
Chatfield asked for new 14in designs protected like Design 14D and
capable of 29 knots. Without detailed investigation, four outline designs
were offered:
14G: three quadruple 14in, 27 knots, protected as 14D.
14H: three triple 14in, 30 knots, protected as 14D.
14J: three quadruple 14in, 28 knots, protection less than 14D.
14K: three quadruple 14in, 29 knots, protection less than 14D.
