A question re RN twin 4 inch HA/LA guns

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Kev D
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A question re RN twin 4 inch HA/LA guns

Post by Kev D »

A question for any gunnery experts reading this if I may.

Would anyone know what would happen with regards gun elevation when all power was lost to the twin 4" HA/LA guns as used as Exeter's secondary armament? That is, would they the be locked in whatever elevation they were at, or would they automatically depress to about (+/-) level?

TIA.

Below a couple of images pulled from video of HMAS Hobart doing shore bombardment with those type of guns.
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Dual-4-inch-loading.jpg
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Dual-4-inch-barrels.jpg
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We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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marcelo_malara
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Re: A question re RN twin 4 inch HA/LA guns

Post by marcelo_malara »

Hi Kev. For what I can see (http://navweaps.com/Weapons/WNBR_4-45_mk5.php) these mountings were manually trained and elevated.

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Kev D
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Re: A question re RN twin 4 inch HA/LA guns

Post by Kev D »

Thanks Maecelo. But that data 'seems' to be just for the single mount Exeter originally had. Given they were replaced with the twin barelled mounts during her refit in 1940 I wonder if that manual elevation still holds true?
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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marcelo_malara
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Re: A question re RN twin 4 inch HA/LA guns

Post by marcelo_malara »

Sorry, I did not know they had been upgraded. Anyway, http://navweaps.com/Weapons/WNBR_4-45_mk16.php are listed also as manual training/elevation, EXCEPT those fitted with RPC. Had Exeter guns been so fitted? In this case, I believe that if power goes off the gun remains elevated, because they are approximately balanced at the trunnions.

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Re: A question re RN twin 4 inch HA/LA guns

Post by Kev D »

marcelo_malara wrote: Thu May 26, 2022 2:30 pm Sorry, I did not know they had been upgraded. Anyway, http://navweaps.com/Weapons/WNBR_4-45_mk16.php are listed also as manual training/elevation, EXCEPT those fitted with RPC. Had Exeter guns been so fitted? In this case, I believe that if power goes off the gun remains elevated, because they are approximately balanced at the trunnions.
Regards
I didnt look at that page Marcelo. Very good! But, pardon my ignorance, what does 'RPC' relate to / mean in your above?

BTW, below a pic of Exeter's 4" mount (the historical image has been 'flipped' horizontally to align with diagarmas). Looks like a 'normal shield, to me. (?)
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We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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marcelo_malara
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Re: A question re RN twin 4 inch HA/LA guns

Post by marcelo_malara »

Ohh, yes, RPC stands for Remote Power Control, a then nascent technology for remotely controlling a gun mounting. The movement of the director was sensed and duplicated in the remote mounting. Before it "follow the pointer" was used, there was one dial with two pointers in the mounting, one dial showed the position of the director and the other of the mounting, an operator moving a training/elevating wheel would try to make them coincide, and in this way follow the movement of the director.

In the case of this mounting, follow the pointer would have been used, so the actual training/elevating was manual. In case RPC was installed, electric power was used, but I do not believe lost of current would make the guns muzzle fall, or go up in case the breach was heavier.
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Re: A question re RN twin 4 inch HA/LA guns

Post by dunmunro »

The Gunnery Pocket Book section on the 4in twin mount:

https://maritime.org/doc/br224/part1.htm#par117

B.R. 257, Handbook for the 4 Inch Q.F. Mark XVI* Gun on the H.A. Twin Mark XIX and Single Mark XX Mountings:

https://maritime.org/doc/pdf/br257.pdf

AFAIK, in 1941 4in twin mounts were hand operated but RPC had been used in trials in 1938. By 1942 RPC was being fitted to 4in twin mounts.
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Re: A question re RN twin 4 inch HA/LA guns

Post by dunmunro »

Kev D wrote: Wed May 25, 2022 7:49 am A question for any gunnery experts reading this if I may.

Would anyone know what would happen with regards gun elevation when all power was lost to the twin 4" HA/LA guns as used as Exeter's secondary armament? That is, would they the be locked in whatever elevation they were at, or would they automatically depress to about (+/-) level?

TIA.

Below a couple of images pulled from video of HMAS Hobart doing shore bombardment with those type of guns.
Can you give a link to the actual videos?
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Re: A question re RN twin 4 inch HA/LA guns

Post by Kev D »

dunmunro wrote: Fri May 27, 2022 12:54 am
Kev D wrote: Wed May 25, 2022 7:49 am A question for any gunnery experts reading this if I may.
Would anyone know what would happen with regards gun elevation when all power was lost to the twin 4" HA/LA guns as used as Exeter's secondary armament? That is, would they the be locked in whatever elevation they were at, or would they automatically depress to about (+/-) level?
TIA.
Below a couple of images pulled from video of HMAS Hobart doing shore bombardment with those type of guns.
Can you give a link to the actual videos?
Thanks for the input Marcelo and Duncan.

Duncan, I do not have a direct link to that video, just some screen grabs. I just did a search for it and could not directly find it, as I just don't have time to look though all the Hobart AWM pages, as going away on a business trip out-of-country Sunday, so a bit swamped here at moment preparing. Came up with another (first film going down page at first link below) with some interesting footage from August 7th Guadalcanal at end, but not the guns as above. Anyway, if you care to look through all the many Hobart pages, the other footage may be there.

Also, although a bit off topic, further below a link to an interesting page on HMAS Hobart.

https://www.awm.gov.au/advanced-search? ... rue&page=1

https://www.navy.gov.au/hmas-hobart-i
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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marcelo_malara
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Re: A question re RN twin 4 inch HA/LA guns

Post by marcelo_malara »

Here is the video.

https://www.awm.gov.au/collection/F01735

Regards
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