The British 16" Mark I
Gun and Mounting
By Terry Duncan
Updated 01 January 2004
Summary
This is a description of
the path a shell took from the magazine to the gun and details of the crew
duties in these controversial weapons. Also included are details of some
of the major differences between these mountings and the type originally
intended for the G3 Class ships from which they were derived, and of the
corrective measures taken, or under review by 1938.
Loading Arrangements
The projectiles were
stored horizontally in bins set around the shell rooms, which were themselves
set around the shell handling room. They were lifted from their stowage
by powerful grabs and carried on overhead conveyors to a power-operated
traversing tray and a hydraulic rammer. When operated, the rammer thrust
the projectile through an aperture in the shell room bulkhead, onto a pivoted
tray in the adjacent shell handling room. A watertight door opened to
allow the projectile to pass and closed as soon as the shell room rammer had
withdrawn. By having a traversing tray, it was possible to load one of
its two troughs while the other was in the ramming position.
The shell handling room
surrounded the revolving turret trunk, to which a pair of contra-rotating,
power-driven, geared rings were attached. These could be clutched to
drive four shell bogies, set 90 degrees apart. When three projectiles,
from three separate shell rooms had arrived on the pivoting trays, the bogies
were traversed around the trunk to a lined-up position, and then locked
"to ship." Each pivoting tray was then revolved until it lined
up with a shell bogie and an integral tray rammer transferred the shell.
The rotating power-driven gear-rings were next connected to the bogie bodies
through a complex arrangement of power drives and clutches. The bogie,
now connected to the rotating rings, was of cradle style with a geared quadrant
and, in being turned through 90 degrees , it caused the shell to take up an
upright attitude. When the three bogies had thus tipped, they were
"unlocked from the ship", reclutched to "traverse" and
driven around the trunk until each was in line with a shell hoist. The
three shell hoists - one for each gun - were themselves displaced 90 degrees
apart, so that one of the four bogies was unused. This, referred to as
the master bogie, was normally kept upright and was used solely as a position
from which all four bogies were traversed. It was, of course, used as a
spare when one of the others became defective as the bogie traverse could be
controlled from any of the four positions, their operating levers being
mechanically linked together.
Having located the
bogies opposite the shell hoists, the complete bogie ring was locked to the
trunking and would then revolve with it should the turret train. Each
shell, now resting on its base, was next moved towards the hoist by the bogie
rammer (again powered by the common power drive), all bogie movements being
mechanically interlocked to prevent accidental malfunction. For example,
it was impossible to unlock "from ship" until all three working
bogies had been tilted upright, nor would the bogie rammer function until the
bogie had been locked to the trunk.
Between the shell bogie
and the hoist base there was a cylindrical drum, called a scuttle which
accepted the shell when it was rammed inwards. The scuttle was rather
like an enormous pistol cylinder, with two shell positions diametrically
opposite each other, and it too, had to be locked before the bogie rammer could
operate. Once the shell had been transferred and the scuttle unlocked,
the latter was engaged with the shell hoist mechanism. Its down-stroke
operation spun the scuttle around half a turn, placing the shell at the bottom
of the hoist tube, and at the same time exposing the empty shell
position. These automatic scuttle drives gave persistent trouble and were
prone to shear completely. In 1936 the automatic feature was removed, the
scuttles being modified for hand rotation, and an extra rating was added for
each gun.
The shell was moved
upwards towards the gunhouse by a pusher hoist that worked on the ratchet
principle. As soon as all shells had been transferred to their respective
hoists, the bogies were unlocked and traversed back to the nearest convenient
pivoting tray; and so the process went on until the three hoists were
full. By this time, they held a vertical column of four shells each (the
highest shells having reached the gunhouse) and there were thus twelve tons of
shell in the hoist trunks.
In the cordite handling
room the six cordite charges were laid in trios into the hopper trays, swung
into the hopper trunking and then power rammed horizontally into a
double-cylinder canister. A wire rope skip tipped it vertically upwards
and hauled it to the gunhouse in one movement, where it appeared alongside the
waiting shell, ready for loading.
The Gunhouse Loading
Arrangements
Remembering that there
were three guns in each mounting, we need only consider the loading process for
one gun. However, it is worth mentioning that the left gun breech hinged
open on the left-hand side, whereas the right and centre guns had right sided
breeches. This was not particularly significant since, clearly the centre
gun had to be "handed" on one side or the other, but it did, of
course make the layout of the hoists in the turret asymmetrical. British
interrupted screw breech mechanisms opened, door-wise, either to the right or
left, but the U.S. favoured a mechanism hinged at six o’clock, so that,
even in a multi-gun turret, the breeches were identical, gun to gun.
A gun's crew consisted
of three men. The Captain of the Gun (CoG) operated the loading control
levers and the chamber wash out squirt; No2 looked after the electric firing
circuits and the air-blast gear (to discharge the cordite fumes from the
chamber when the breech was re-opened); and No3 worked the shell and cordite
hoists by operating two levers. He could see immediately when a shell was
available by its presence at the top of the shell hoist, but had to wait until
a mechanical telegraph plate moved to reveal "Cage Loaded" before
raising the cordite.
The CoG now took over,
operating his two hand-levers. These were known as "churn
levers" by the crews due to their motion around three sides of a square
box. Complex mechanical interlocking rods (similar to the type found
beneath a railway signal box of the period) were fitted to prevent
malfunction. The first movement was towards "Lock Slide",
whereupon the gun was divorced from the layers control and automatically moved,
as required, in either elevation or depression, until it reached the fixed
angle of 3 degrees. There, heavy pawls engaged it, holding it
rigidly. Shifting the same lever sideways aligned it with the "Tilt
Tray" tipped the tray downwards to the 3 degree loading angle. The
cordite canister, linked to the tilting gear, tipped automatically to the same
angle so that both shell and cordite were now aligned alongside each
other. At this stage, however, they were to one side of the breech, clear
of the guns recoil, so, as soon as the tipping motion of the shell tray was
complete, it tripped a traverse gear which carried it sideways on a carriage,
pulling the cordite canister after it. At this point, the situation was;
1. Gun
locked at loading angle
2. Breech
open
3. Shell
tray tilted and traversed to position in line with chamber
The CoG now operated his second lever towards "Ram Shell", whereupon
a seven-section telescopic rammer extended from a rammer casing anchored to the
turret deck plate, and thrust the shell through the chamber until its copper
driving band bit into the commencement of the rifling. When he returned
it to the "Withdraw" position, it became aligned with the lateral
"Traverse" slot. Moving it in this new direction caused the
whole assembly to traverse a step inwards, so bringing the first three charges
into line between the rammer and the chamber. The same lever, pulled
backwards into the "Ram Cordite" slot, again extended the rammer, but
its stroke was automatically reduced as the cordite did not have so far to
travel as the shell. The rammer was withdrawn by returning the lever to
the "Withdraw" position again, the assembly traversing another step
inwards automatically, to bring the second trio of charges into the ramming
position. The rammer was then extended for the third time, pushing the
second three charges into the chamber and shunting the first three before them.
The first movement of
the reverse sequence traversed the shell tray and cordite canister back towards
their hoists, where the empty cordite container re-entered the hoist skip-cage
and the shell tray reconnected with the hoist tilt gear. Thereafter, the
shell tray was tilted upright, the breech closed, a firing tube inserted into
the lock, the slide unlocked, and the layer resumed elevation control of the
gun (the gun-drill order "Free the slide" was adopted in the messes
as a request to "pass the butter" and is still sometimes used today,
although its significance is seldom appreciated by those using it. So in
a small way these guns are still remembered!).
Once the cordite
canister had returned to the top of its hoist trunk, and the tray had been
tilted upright by the CoG, No3 sent the cordite cage back down to the lower
quarters for reloading and brought another shell up into the shell tray by
operating his "Raise Cordite" and "Raise Shell" control
levers. The three drill positions were;
1. Gun
Loaded. Guns on pawls and loaded, no tube in vent; firing circuit
interceptor open; shell tilting tray loaded; shell hoist full; cordite cage up,
and full.
2. Half-cock.
Gun loaded; tube in vent; interceptor open; gun free from pawls.
3. Gun
Ready. Gun loaded; tube in vent; gun layer "on", by matching
receiver pointers; interceptor closed.
In the rear corners of the gunhouse there were two auxiliary stowage positions
for shells, each with an associate radial crane capable of plumbing a
striking-down hatch, through which shells could be returned directly to the
shell room. The normal shell supply arrangements, described above, were
not reversible and there had to be a means of emptying the hoist and stowing
the shells there from, should the type of projectile be changed during an
action. The hydraulic radial cranes could plumb the adjacent outer hoist,
the shell bin and the striking-down hatch, making the process for the outer
guns fairly straightforward, but the centre shell hoist was beyond the span of
either crane and special slinging arrangements had to be arranged to unload it!
The 16" Gun
Mounting Crew
The full turret
crew were as follows;
Gunhouse, "silent
cabinet" and training engine space.
1
captain of turret (quarters rating, 1st class).
3 gun's crews of 3 men each.
1 rangetaker, plus one, for rangefinder.
1 LDS layer.
1 LDS trainer.
1 sight-setter.
1 OOQ.
1 telephone operator.
Plus for
quarters firing:
1
range officer.
1 rate officer.
1 Dumaresq calculator operator.
3 Gunlayers (quarters ratings, 3rd class), senior gunlayer in charge.
1 turret trainer.
Shell handling room.
1
second captain of turret (QR1).
4 shell bogie operators.
4 pivot tray operators.
3 shell scuttle operators (after modifications).
Shell room.
1
petty officer in charge of 24 men ("B turret only - 6 men per loading
tray; "A" and "X", with only three trays, had 18 men).
Cordite handling room.
1
petty officer plus 15 men (5 per gun).
Magazine.
1
petty officer, plus 24 men ("B"), or 18 ("A" and
"X") - 6 men per supply scuttle manned).
Guncrew Duties.
1. Gunhouses
etc (see earlier descriptions).
2. Shell
Handling Room:
(i) Pivot tray number - loads shell bogie and operates serving
port.
(ii) Shell bogie number - controls the bogie and loads the revolving
scuttle at the hoist.
(iii) Shell scuttle number - revolves scuttle by manual operation.
Loading Procedure
(i) opens serving
port.
(i) of shell room, advances shell room rammer; withdraws rammer, trains
pivot tray into line with shell bogies.
(ii) puts bogie tilt lever to "Tilt Lift"; when bucket is
horizontal, replaces tilt lever to "Locked to ship".
(i) advances pivot tray rammer; withdraws pivot tray rammer.
(ii) puts bogie tilt lever to "Tilt Right"; when bucket is
vertical, replaces tilt lever to "Locked to ship".
(i) trains pivot tray back to serving port.
(ii) of master bogie, puts churn lever to "Train Right" or
"Train Left".
(ii) of other bogies, put their churn levers to "Locked to Trunk"
(Note: All bogies lock to trunk automatically when in line with
hoist). In the case of "B" only, its fourth tray was initially
loaded but then remained in line with its serving port.
(ii) of loaded bogies, ram projectiles into scuttles, withdraw rammers and
clutch scuttle "To Hoist" as soon as rammers have withdrawn
(Note: Drill changed when scuttles were modified).
(ii) of master bogie, trains back to pivot trays.
(ii) of working bogies, lock bogies "To Ship" and tilt buckets to
horizontal (Note: The master bogie is kept free with bucket vertical).
The cycle was repeated until the shell hoists were full and the tilting
trays in the gunhouses were loaded.
State on completion
of "Load Hoists"
1. Shell
hoists full.
2. Shell scuttle loaded and clutched "To Hoist".
3. Shell bogies loaded and "Locked to Ship".
4. Pivot trays loaded and in line with serving ports.
5. Serving ports closed.
At the order
"Load"
When scuttle has
rotated, (ii) of working bogies "Lock to Trunk", reload scuttles,
clutch scuttles "To Hoist" and free bogies from trunk.
Duties of shell room
crew
PO
takes general charge in the main shell room.
No1 (in charge of the crew) works rammer of traversing tray.
No2 traverses tray.
No3 removes grab at traversing tray.
No4 works lifting and traversing levers of the overhead shell gantry.
No’s 5 & 6 work in shell bins, placing grabs.
Duties of
cordite handling room crew
PO
takes general charge of all cordite supply.
No1 operates cordite rammer and is in charge of hoppers.
o2, 3, & 4 - cartridge supply numbers.
No5 operates flashtight scuttle between handling room and magazines.
Loaded State
1.
Cordite cage up and loaded.
2. Cage telegraph showing "Cage Not Down".
3. Both hoppers loaded and closed.
4. Flashtight scuttle open to cordite handling room, closed to
magazine, and empty.
5. No other cordite in handling room.
Procedure to test cordite loading gear.
1.
"Open right hopper" No3 opens right hopper.
2. "Advance rammers" - should not be possible.
3. "Close right hopper, open left hopper" - No3 closes
right hopper, No2 opens left hopper.
4. "Advance rammers" - should not be possible.
5. "Close all hoppers" - No2 closes left hopper.
6. "Out cordite rammers" - No1 advances rammers.
7. "All cordite rammers out" - report passed to captain
of turret.
8. "Open both hoppers" - should not be possible.
9. "Withdraw rammers" - No1 withdraws rammers.
10. Cordite cages can now be raised.
Safety
Interlocking Gear
The following list of
the interlocks is taken from the operating instructions, and is to say the
least, a little daunting!
Gunhouse Controls
1. Cannot
put lever to "Open Breech" until slide locking pawls are out.
2. Cannot put lever to "Close Breech" until shell tray
is tilted up.
3. Cannot put lever to "Tilt Down" while the hoist is on
up stroke.
4. Cannot put lever to "Tilt Down" until breech is open.
5. Cannot put lever to "Tilt Up" while ramming or
traversing.
6. Cannot put lever to "Ram" until shell tray is tilted
down, or while trays are traversing.
6A. Cannot put lever to "Ram Shell" after trays have traversed
to cordite loading position.
7. Cannot put lever to "Traverse" with trays tilted up.
8. Cannot put lever to "Traverse" unless rammer is right
back.
9. Cannot put cordite hoist lever to "Lower" unless
cordite tray is tilted up.
9A. Cordite tray cannot be tilted up unless cordite tray is at top
of hoist to receive canister.
10. Cannot put cordite hoist lever to "Raise" when bottom
flash door is open, or until it has been opened and closed since the hoist was
last lowered.
11. Cannot put shell hoist lever to "Lower" until hoist
has completed an upstroke.
12. Cannot put shell hoist to "Raise" until shell hoist
has completed a down-stroke.
13. Cannot put shell hoist to "Raise" unless shell tray
is tilted up and empty.
13A. Cannot put lever to "Tilt Down" while shell hoist
lever is being put to "Raise", and vise versa.
A. Cannot put ramming lever to "Withdraw" until shell
ramming stroke is complete.
B. Cannot put ramming lever to "Withdraw" until cordite
ramming stroke is complete.
Additional notes on
gunhouse controls
1. Slide
could also be locked by a hand operated bolt.
2. No 1A interlock (slide cannot be unlocked unless breech is
closed) removed during development; replaced by No1 (later reinstituted - see
modifications).
3. The cordite cage could not be raised unless the cordite room
rammers had been withdrawn.
Shell Handling Room
15. Cannot
put pivot tray levers to "Slew" or "Ram" unless shell room
rammer head is back.
20. Rammer lever on pivot tray is locked until shell bucket is
horizontal.
21. Bogie is "Locked to Ship" until telescopic portion of
pivot tray is home.
21A. Shell bogies cannot be "Unlocked from Ship" unless
pivot tray is trained to a serving port.
22. Shell bucket of bogie cannot be tilted to vertical until pivot
tray is clear.
23. Bogie cannot be "Unlocked from Ship" unless shell
bucket is vertical.
24. Cannot put pivot tray lever to "Slew" unless bogie is
"Locked to Ship"
28. Cannot put bogie lever to "Ram" unless bogie is
"Locked to Trunk" and shell scuttle is locked in the receiving
position.
29. Cannot "Unlock bogie from Trunk" unless bogie rammer
is right back.
31. Cannot "Unlock bogie from Trunk" until shell scuttle
has been clutched "To Hoist".
38. Cannot put pivot tray lever to "Slew" unless rammer
lever is to "Withdraw".
39. Cannot put lever to "Slew" while pivot tray lever is
out.
40. Cannot put lever to "Ram" unless slewing lever is
hard over to "Train Bogie".
41. Cannot put lever to "Ram" unless pivot tray is in
line with serving port.
Shell Room
14. Cannot
put rammer lever to "Ram" until watertight door is open.
14A. Cannot put rammer lever to "Ram" until pivot tray is
in line with serving port.
16. Cannot put watertight door operating lever to "Close"
until shell room rammer is fully retracted.
Cordite Handling
Room.
33. Cannot move loading lever to "open Bottom Flash Door"
unless both hopper doors are closed.
34. Cannot put loading lever to "Ram" until bottom flash
door is fully open.
35. Cannot put loading lever to "Withdraw" until rammer
has completed its stroke.
36. Cannot put loading lever to "Close Flash Door" until
rammer is right back.
37. Cannot open hopper doors until bottom flash door is closed.
Early Problems
The mountings were
installed during 1926-27 and the gear gave trouble almost immediately. In
July 1927 Rodney's (and Nelson's too, upon inspection) roller paths showed that
the inner edge of the lower roller paths were cutting into the flanges of the
turret rollers. Initially, training speeds were reduced while a set of
vertical rollers were made to take the side thrust of the rotating mass.
Upon the fitting of these, the training speed restriction was lifted, and the
no further excessive wear took place.
1932: The shell
handling room pivoting tray rammers in Nelson's "B" turret were
changed from wire operation to hydraulic ram, and "signal box"
interlocks were introduced for all pivoting tray operations.
1931-32:
Arrangements for leading electric power on to the rotating structure were
changed from cable winding gear to cable platform gear.
1933-34: All
turrets in both ships were modified as above.
1933-34: The
original automatic tray traverse mechanism in the gunhouse was changed as an
outcome of a modification suggested by Chief Ordnance Artificer (COA) Waterson
(thereafter known as "Waterson's Mod".
May 1934: For the
first time, Nelson's mountings were subjected to a test of prolonged firing of
16 rounds per gun.
Dec 1934: A
conference, attended by representatives of the Home Fleet, Admiralty, and
gunnery experts from HMS Excellent, was held in Nelson to discuss material
breakdowns.
July 1935: The
gunslide on the right of "A" mounting in Nelson was found to be
cracked, and similar cracks were found in the centre gun slide of "B"
in Rodney.
May-June 1936:
Persistent shearing of the drives from the shell hoist gear made it necessary
to disconnect the shell scuttle drives from the shell hoist gear; thereafter
they were rotated by hand and three extra men added to the mounting crew to
operate them.
Summary of
modifications in hand or under consideration in 1938
Detail.
1. Improved air blast. (Fitted in Nelson)
2.
Reintroduction of No1A interlock. (Fitted in Nelson)
3. Solid
forgings for traversing tray cross heads. (Fitted in Nelson)
4.
Modifications to run-out control arrangements. (Under consideration)
5. Redesign
of breech obdurator pads. (New pads pressed to 8 tons per sq. in and
supplied to both ships).
6.
Modification to depression control gear. (Fitted in Rodney)
7.
Modification to elevating gear. (Gear manufactured, awaiting fitting to
both ships)
8. Redesign
of bogie training arrangements. (Under consideration)
9.
Conversion of shell scuttles to hand operation and interlocking gear
modified. (Complete in both ships)
10.
Modification to control valves of shell room overhead gantries. (Fitted
in Nelson)
11. Fitting
of interlock to prevent double loading of cordite cage. (Under
consideration)
12. Fitting
of oil coolers. (Complete in both ships)
13.
Modification of pump governors. (Two fitted in Nelson for trials)
14.
Cross-connection to run turret pumps in parallel. (Under consideration)
15. Fitting
of access doors to cordite hoists above flash doors. (To be fitted in
both ships.
The Early Designs
The design for the
16" gun mounting fitted to the Nelson class differed in many ways from the
initial designs, as more safety features were worked in, and weight savings
became more important. Indeed, many of the later problems experienced
with these guns were due to the desire to have as far as possible, a fully
automated supply system which was flashtight, made out of the lightest, and
therefore sometimes less robust materials.
Some of the major
changes during the transition of the design from the "G3"
Battlecruisers to the "O3" Battleships that became the Nelson's are
as follows;
1. The
hydraulic mains (normally water in Royal Navy ships), were switched to oil, to
allow the use of steel piping as opposed to the heavy duty brass pipes in
previous classes. This gave a reasonable weight saving, and was less
costly. However, the steel pipes were never felt to be as good as the
earlier brass ones and seem to have suffered from leaks more frequently.
2. The
independent shell bogies for each gun were abandoned to save weight and due to
the difficulty in co-ordination. The three fixed position bogies were
lighter than three independent ones would have been, but this caused the
loading cycle to be slowed considerably. This was due to the fact that
all the guns had to be loaded together, whilst due dispersal problems, it was
desirable to fire the wing guns separate from the centre guns in each turret.
3. The
cordite bogies (similar to the shell bogies) were replaced by cordite hoppers
in the final design. This led to a requirement for more men in the turret
crew.
4. The
supply rate of cordite to the turret also caused problems, as whilst the shells
took 35-45 seconds to reach the guns, the cordite took 45-55 seconds to reach
the same point. This was partly due to the greater distance the cordite
had to travel, and partly due to the safety interlocks reducing any chance of
speeding up the process. Initially, there was a lesser degree of
automation in the mountings, and less interlocks also. These were added
during the design process, as ways of saving weight and reducing manpower
became more important, especially after changes 2 and 3 were adopted.
5. The
roller paths that caused problems in 1928, were 18 inches less in diameter than
those for the "G3" design, and indeed the corrective measure of a set
of vertical rollers, was already allowed for in the initial designs.
Again, this feature seems to have been changed in an attempt to save weight.
6. The
turrets for the "G3" design were to weigh 1830-1900 tons (though a
figure of 1730 is also quoted, though this seems a little light), whilst those
for the Nelson's were 1464-1485 tons. This difference was due (other than
the slightly smaller size of the mounting) to the replacement of various pieces
of machinery with the lighter and mostly more fragile versions that later
caused so many problems. It can be seen that in the 1939 Lion design, the
turrets are heavier than those of Nelson, whilst having a slightly reduced
scale of protection.
These are the major
changes to the gun mountings and were certainly the ones that caused most
problems for the designers and for the crews once in service. There were
many other changes in the finer details adopted for the "O3" design
(Nelson) that have also led to the ships themselves being thought of as sub-standard
or badly built. The most criticism comes from the supposedly poor
performance of HMS Rodney during the final stages of the Bismarck chase, and
relate to the damage she caused to herself due to the blast effects from the
main armament.
One of the two most
notable defects was the adoption of aluminium alloys for most of the minor
ships fittings, such as kit lockers, mess racks, store cupboards and indeed the
fittings holding some items in place, especially with regards to the crews
lockers and wash facilities. These were all shaken up badly by the main
armament being fired, and indeed many became loose and some were even thrown
around the cabins and mess decks. Nobody was injured by these unexpected
happenings, though many were shocked by the level of destruction that
resulted! In WWII, the shortage of
aluminium for aircraft production led to the use of heavier metals for such
fixtures in ships of the Fiji class onwards, resulting in an additional 100
tons displacement.
The other major fault
was the adoption of Douglas fir for the upper deck, instead of the normal
teak. This was deemed acceptable by the designers due to the weight
saving, even though the resulting loss of appearance and durability were
appreciated. However, the fir proved to be less acceptable in service, as
it proved to be less resistant to the blast effects from the 16"
guns. Indeed, it seems to have surprised many people quite how much the
fir was ripped up when the guns were fired over it. This appears to have
occurred on all bearings at low elevations, and from "A" and
"B" when firing forwards, even at higher elevations. The
resulting destruction of the decks was viewed with extreme distaste by some
senior officers who wanted the ships to be "tight and tidy" at all
times, very similar to the Victorian officers who disliked gunnery practice as
it caused soot marks and chipped the paintwork!
Neither of these two
faults, though very noticeable caused any loss of fighting efficiency
whatsoever! With hindsight, as the ships
turned out 1500 tons (Nelson) and 1100 tons (Rodney) under the Treaty
restrictions, it is a great pity that some of the measures taken to save weight
were ever adopted in the first place!
One of the other things
noted about Rodney, is that she seemed to wear out quicker than Nelson.
This was largely because Nelson was nearly always used to test modifications
and new equipment. Rodney was fitted second, as and when/if money could
be spared. When WWII broke out, she was already in need of an engine
refit. She was destined to never receive this much needed refit
throughout the war, despite her extensive service, as she was looked upon as
too valuable a unit to spare from duties for any period of time, if she was
still capable of service. By the time she could be spared, in 1944, there
seemed to be little point in sending her for the refit, as the need for her
type had largely passed.
The Shells
The following are the
specifications for the G3 and N3 designs, and show how the design altered until
the 16"/45cal Mark I of the Nelson's was arrived at. Also, for
comparison, I have included the few details that are relevant from the 18"
designs for the N3’s.
|
Gun |
Projectile |
Muzzle Velocity |
|
16.5"/45cal |
2,552 lbs. |
2,385 fps. |
|
16.5"/45cal |
2,552 lbs. |
2,425 fps |
|
16"/45cal. |
2,330 lbs. |
@ 2,450 fps. |
|
16"/45cal. |
2,048 lbs. |
2,670 fps. |
|
16"/45cal. |
2,048 lbs. |
2,575 fps. |
|
18"/40cal. |
3,320 lbs. |
2,500 fps. |
|
18"/40cal. |
2,916 lbs. |
@ 2,750 fps. |
|
18”/45cal. |
2,916lbs |
@
2,900fps. |
|
|
18”/45cal.
|
3,350lbs |
@
2,550fps. |
|
With regards to the 16”
(and 16.5”) shells, there was considerable discussion as to the relative merits
of the high weight – low velocity combination adopted for the 13.5”, 15” and
18” guns already in service, when compared to the low weight – high velocity
combination favoured by the German navy.
Several sets of trials were carried out, and some of the early ones did
favour the latter combination, although faulty shells seem to have distorted
the results from the first tests. Later
tests proved far from conclusive as to the superiority of the lower weight
shells. Sadly, the documentation for the
crucial trials, which it appears were conducted between September and October
1920, that led to the adoption of the light weight shell – high velocity gun
combination is missing in its entirety, and despite much searching, I have
found no author or source that can shed any reliable light upon why this was
the chosen solution. All the
documentation remaining seems to indicate that the heavier shell produced at
least as good a result (and far better at higher angles of impact) as the
lighter shells after the initial trials, which were conducted with a batch of
shells that did not pass quality testing for acceptability.
When the 18” gun is
considered, there are very few details that survive, although it seems likely
that power loading for the charges was to have been adopted as standard as well
as an auxiliary power source for each mounting from the start. The guns themselves would have been
exceptionally powerful weapons, although a formidable blast effect was to have
been expected from them. This does not
seem to have caused any great concern at the time, and seems to indicate that
the superstructure and fitting would have been strengthened to allow for such
effects (the results from Furious and General Wolfe using the far less powerful
18” 40cal weapon using supercharges were well known in the service).
There are various other
figures from different sources, although they are found less often, and are
possibly less reliable. The greatest difficulty arises in duplication of
figures, such as the 18"/45cal firing a 3,600lbs shell at a velocity of
3,600 fps! Mostly this stems from confusing data for the 18"/40cal
mounted on Furious and General Wolfe in 1918. This gun fired a 3,320 lbs.
shell at 2,270 fps (there are notes that suggest that a 3,600lbs shell for
bombardment purposes was produced, but details are few). However, when
used for shore bombardment, the gun had supercharges that raised the velocity
to 2,400 fps with the same shell. It was with these normal shells and
supercharges that General Wolfe engaged a railroad bridge in Belgium on 28th
September 1918 at a range of 36,000 yards, the longest range at which a Royal
Navy vessel has fired upon an enemy. The
bombardment was ranged from British Army map co-ordinates, and was complimented
by air spotting. Several hits were
scored upon the bridge, along with some near-misses, and the operation was
considered a great success. The gun had
performed at least as well as was expected and proved to be very accurate by
any standards (the hits on the bridge certainly being the longest ranged hits
achieved by any naval gun at the time), certainly given the rudimentary
spotting and ranging available at the time.
For much of the above
information I have used the following sources;
"The Big Gun" by Peter Hodges.
"British Battleships of World War II" by Alan Raven and John Roberts.
"Battlecruisers" by John Roberts.
"The Grand Fleet" by D.K. Brown.
"Warship Vol 1" article by John Campbell.
"Ships Cover for G3 Class Design" National Maritime Museum.
I must also give thanks
to the staff of the National Maritime Museum and the Imperial War Museum in
London for their help over the years, as the above subject is somewhat hard to
find any exact information without their help!