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[Colin Bishop]

I have been looking through R A Burt's book on pre dreadnought battleships and am intrigued by the photos which often show the central main deck ports for the 6 inch gun secondary armament in the closed position with no guns visible. Other photos show the gun barrels poking out when firing. This does seem to suggest that the 6 inch guns in the battery were run well in when not in use and must have taken up a great deal of internal space. The most forward and after guns do seem to permanently show their barrels though. Does anyone know just what the internal arrangements for stowing and running out these guns actually were?

Colin

[Geoff]

I think much depends on the age of the ship and the particulat mounting used. Later ships had pedestal mountings and the guns could not be run in. Earlier ships were on slide type mountings and the barrel could be slid virtually all the way back.
 
Its not just the gun one has to consider but the mountings which were constantly being improved and sometimes very different from each other.
 
Cheers
 
G

[Colin Bishop]

Thanks Geoff. Before they used the pedestal mounts the guns must have taken up a lot of room internally in the battery.

Colin

[ballastanksian]

The Vevaussier (SIC) mounts were very long for the largest of guns but seem to have become more compact as recoil cylinders and buffers were introduced. Could the barrels have made it past the opening edges if the weapon was rotated 90 degrees?

[victorian]

I've often wondered about this. This picture of the secondary armament in Amphitrite (Vickers, 1898) shows notches in the gun port covers allowing them to be closed around the barrels.



This view of the gun deck in Niobe (also Vickers) shows the 4" guns on pedestals with no provision for running in. Every photo of the ship shows them run out, even when alongside for coaling. But it's not impossible that the smaller guns could have been unshipped of course.

[raflaunches]

Perhaps this might help...

















These are of the Majestic class Predreadnought but I couldn't find anything I have so far of the main deck 6 inch armament and how they retract into the hull but the upper ones seem to rotate backwards (the 12pdrs) or stay where they are and get locked into place by the gun doors (the 6 inch).

[derekwarner]

This is an interesting casemate for the 6" guns Nick B......we see that they can be trained 29 degrees astern of midships, however no nomination of the operation train fwd

Lets hope they had good non-firing zone limits as they could be trained & stowed at 90 degrees fwd of midships ......

Another interesting point is that the casemate shell plating is depicted as somewhat thicker [~~8"?] over the rotating mantlet plate of ~~6"?         Derek

[raflaunches]

Let's hope so Derek   Don't fancy standing in front of the barrel even if it wasn't loaded. I've got a picture of sailors sitting in front of them presumedly during a quiet day in the navy!


I never noticed the thickness difference between the gun shield and the superstructure armour, maybe it's a weight saving thing!

[Colin Bishop]

Reading Burt's book, there are also blast implications which affect the training arcs. Of course you have to remember that at this period, the job of the secondary batteries was to destroy the superstructure of the enemy ship at fairly close range and generally on the broadside. The big 12 inch guns with their slower rate of fire were intended to deliver the coup de grace to actually sink the enemy. Brutal stuff really! Not so far removed from the Nelsonic policy of closing with the enemy and battering them to destruction.

Colin

[derekwarner]

''sitting front of a barrel?".........yes Nick....I understand in days of olde junior weapons artificer types cleaned the spiral fluting of the barrel with chimney sweep circular steel wire brushes on long metal rods.....

Again, the breach block was locked closed .....after the brushing/sweeping was completed the air blast was used to displace all of the black burnt ash.... Derek

[Colin Bishop]

Again, the breach block was locked closed .....after the brushing/sweeping was completed the air blast was used to displace all of the black burnt ash....

Did they have air blast available in pre dreadnought days? I find it quite interesting that all the naval books refer to armament in general terms but in reality there were all sorts of practices going on to actually operate the weapons which were continually being improved. Much of this knowledge seems to have been lost but at the time very high skill levels were required. As Derek says, firing the guns left a lot of crud inside the barrels which had to be regularly cleared out.

Colin

[ballastanksian]

The diagram in the Big Monitors of the 12 inch gun turret shows air bottles but wether these were added during the modification of the mounting to increase elevation to 30 degrees I cannot say.

[derekwarner]

Air blast for ordinance was developed by Vickers as a prerequisite when the open barbette evolved into the closed turret...circa~~approx. 1902......attempts were also made to have a positive air pressure of 5 PSI [over atmosphere] within the closed turret...however this proved near impossible to maintain

Air bottles [receivers] were fixed components in the turrets however were high pressure [1000 PSI] & supplied from compressors in machinery spaces below decks [you carry a greater usable volume of air at higher pressures which required pressure reducing valves]

Hale-Hamiltion was British manufacturer of among other things, pressure reducing valves of bronze/stainless construction ...The RN exclusively used HH valving up to the building of the Oberon class submarines. The RAN shipbuilding programmes up until post WWII also used HH pneumatic valving

A shoebox sized [1" BSP ported] pilot operated HH bronze pressure reducing valve 30 years ago had an RAN book value of AUD$4000.00  ....

Train and elevation function was achieved by electro/mechanical or hydraulically, recoil function was mechanical/hydraulic...........Derek 

[ballastanksian]

The majestics had turrets with 'Sunroofs' covered with canvass so I suppose the gasses would have escaped out that way, and this basically means that the bottles shown as I mention were later additions when the turrets were modified. Inyteresting topic!

[Colin Bishop]

The older pre dreadnoughts were essentially fitted with barbettes rather than turrets. The assumption was that battle ranges would be short so there was no need to protect against plunging fire as shell trajectories would be horizontal. So there was no need for armoured roof protection. Things changed quite quickly though!

Colin

[Geoff]

To add a little more there is an excellent book on the development of guns and their mountings - "The Big Gun". It explains in laymant terms how they were developed and worked with particular emphasis on the mountings and the almost universal use (in the RN) of hydraulic machinery and why this was retained. The systems were develped to a superb level of engineering with nothing to be desired in terms of their accuracy and relisbility. It is interesting to see how they managed to move a gun turret weighing 500/1,000 tons plus by half of one degree without overshooting! Fascinating book.
 
Whilst the books focus is mainly on 12" and above there is a detailed section on 6" and their mountings and again it explains the development. It takes the development from "Majestic" times to the end of WW2. Highly recommended.
 
Today we tend to consider the 6" gun as a secondary weapon but in the "Majestic" times it was considered very much an integral part of the main armamant.
 
When considering the design of these ships we need to reflect that battle ranges were universally short in the 3,000 yard range at this time and shell trajectories were essentially flat. The fire control instruments simply did not exist to hit a moving target from a moving, rolling and pitching platform at greater range. The development of fire control is another story but it dictated large guns and more of them to make it viable - hence Dreadnought.
 
Despite throw away comments about the RN being conservative they were in fact at the very leading edge in design and techniology at this time

[derekwarner]

Yes Geoff....complex mechanical computers at the turn of the Century controlling electro/mechanical/hydraulic systems...... ...far smarter than most of 'we mere mortals'........ Derek

Courtesy if WIKI.......

The Dumaresq was a mechanical calculating device invented around 1902 by Lieutenant John Dumaresq of the Royal Navy. It was an analog computer which related vital variables of the fire control problem to the movement of one's own ship and that of a target ship. It was often used with other devices, such as a Vickers range clock to generate range and deflection data so the gun sights of the ship could be continuously set. A number of versions of the Dumaresq were produced of increasing complexity as development proceeded.

Further reading would suggest that both the US and German navies were on par with the RN at this time, and possibly evening sharing new technology

[Colin Bishop]

Thanks Geoff, I have ordered a copy of the book.

Colin

[raflaunches]

I've just found some pictures on ebay which may explain the mystery of the 6inch guns fitted to pre dreadnoughts, I'll upload a copy of them when I receive them but it looks like they sit on mount and are retracted on a beam like structure into the hull.
Going to buy the book recommended by Geoff too!

[Colin Bishop]

I have been reading the book most of today, fascinating really. The engineering described is amazing.

Colin

[Geoff]

Colin,
 
Glad you like it. I agree it quite fascinating how they solved the engineering problems. What I found interesting is that the book explains the principles in laymans terns with good schematic drawings so you can actually understand how it worked. It's not full of indecipherable drawings which are really too complex to understand.
 
A very interesting book for those into that sort of thing! 
 
Cheers
 
Geoff

[ballastanksian]

Do you have the Author and publisher there Colin and/or Geoff? It sounds like a good bed time read:O)

[raflaunches]

Pictures as promised, these are from 'The Engineer' dated 18 December 1896 of the HMS Prince George.




















Ian- The book is:

The Big Gun: Battleship Main Armament, 1860-1945 1 Jan 1981
[by [Peter Hodges

[ballastanksian]

Thanks Nick, you are a top chap :O) The 6inch must have been a beast to move in anything but a calm sea way, even with proper contrivances.

[derekwarner]

Nick.....I suggest one of the contributors to confusing our minds in how these gun structures were moved  is that all of the drawings or images are stripped down and  only represent a limited view of the actual structure and associated components

One example here [6" Gun Housing Gear] is the barrel resting on two pedestals.....we also see the barrel trunion ring and a trunion pin....we also see an arc segment of the elevation rack on axis or about the trunion pin

So whilst it is speculative, without any evidence of train [slew] machinery is would be fair to consider this image is of a 6" gun in the turret that can slew

Another point to consider is the actual location of the trunion axis...... a carefully balanced 5 ton barrel mass could easily be elevated and depressed by a hand propelled worm reducer.....Derek