Gun range for 8' British cruiser guns?

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Kev D
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Gun range for 8' British cruiser guns?

Post by Kev D »

Assuming HMS Exeter's 8" guns could elevate to 70, could anyone give me the approximate range if elevated to near max (say 65°) please? (And I only say 'assuming' as although most stats say she had only the 50 degree turret, photos from wreck seem to prove different.)

Questions is asked so as to try and ascertain range to a certain group of targets.

Any help much appreciated. :ok:

EDIT: Opps, just found I already had :stubborn: the 45-50 (from Naval Weapons site) from some time ago, so have removed above question re same. So, just the 65-70 elevation range is all I am after please .

PS. Not sure what attachment is now showing as it usually would?

8-inch-gun-elevation---range.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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Re: Gun range for 8' British cruiser guns?

Post by dunmunro »

Kev D wrote: Tue Oct 12, 2021 8:11 am Assuming HMS Exeter's 8" guns could elevate to 70, could anyone give me the approximate range if elevated to near max (say 65°) please? (And I only say 'assuming' as although most stats say she had only the 50 degree turret, photos from wreck seem to prove different.)

Questions is asked so as to try and ascertain range to a certain group of targets.

Any help much appreciated. :ok:

EDIT: Opps, just found I already had :stubborn: the 45-50 (from Naval Weapons site) from some time ago, so have removed above question re same. So, just the 65-70 elevation range is all I am after please .

PS. Not sure what attachment is now showing as it usually would?


8-inch-gun-elevation---range.jpg
We'd need an RN 8in range table to get an accurate figure. However, this 5in/38 range table should allow you to estimate the range at 70deg elevation, by multiplying maximum range by 5in range at max range/range at 70deg elevation, which is ~.6 as per the attached range table.
5in_RT.jpg
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Bill Jurens
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Re: Gun range for 8' British cruiser guns?

Post by Bill Jurens »

This post seems to be 'drifting' a bit, and it seems a previous posting of mine seems to have gone astray.

The ballistics are relatively easy to calculate in simple form, i.e. neglecting the probable inability of the projectile to properly 'trail' at the summit. These calculations can be done, but would require the addition of a fair amount of information generally unavailable, e.g. the projectile spin decay coefficient. Generally, these sorts of things don't affect the overall answers too much. Assumed initial velocity was 2805 f/s, projectile weight 256 lb., Projectile Type 8.

The following figures assume a sort of generic standard atmosphere, so changes in the assumed air densities, etc. might affect things somewhat, but not too much. Figures are given between commas as: Angle of Departure (deg), Range (yds), Striking Velocity (ft/sec), Time of Flight (seconds), and Maximum Ordinate (feet).

50,39650,1486,62.66,105.1,44104
65,26458,1346,73.80,114.6,52106
70,22683,1375,76.78,119.1,56292

These should be pretty close to correct if I haven't made a typing error.

Bill Jurens
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Re: Gun range for 8' British cruiser guns?

Post by Kev D »

Thanks very much for that input Duncan and Bill. And yes ballpark is good enough, given the unknown knowns.

Now, pardon my ignorance Bill but.....could you breakdown just one line of your figures above as not sure what the row means / signifies. For instance - 65,26458,1346,73.80,114.6,52106 ?

Again, pardon my ignorance :oops:
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: Gun range for 8' British cruiser guns?

Post by marcelo_malara »

Any elevation beyond 45° decreases horizontal range, like mortar fire, its only use is as anti aircraft fire.

About Bill posting, there seems to be some mistake, as there are 6 commas but 5 variables.

Angle of Departure (deg) 65
Range (yds) 26458
Striking Velocity (ft/sec) 1346
Time of Flight (seconds) 73.80
? 114.6
Maximum Ordinate (feet) 52106
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Re: Gun range for 8' British cruiser guns?

Post by Kev D »

marcelo_malara wrote: Wed Oct 13, 2021 3:53 pmAny elevation beyond 45° decreases horizontal range, like mortar fire, its only use is as anti aircraft fire.
Understood Marcelo, and thanks for the input, but the main guns weren't being used as AA weapons at the time of Exeter's demise. So what it does show (or will show I assume) is approximately where at least one echelon of the enemy's southern forces were (i.e. at approx what range) near 'the end' when the killer blow landed (and knocked out all power) and left all her guns 'locked in place / train' so to speak
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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Re: Gun range for 8' British cruiser guns?

Post by Bill Jurens »

My apologies for the confusion. My mistake; as I suspected I might, I made a typing error.

Variables are Angle of Departure (deg), Range(yds), Striking Velocity (f/s), Angle of Fall (deg),Time of Flight(sec), and Maximum Ordinate (ft).

I am wondering what this information might be used for, as refinements might be made if the variables that are of most immediate relevance were known.

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marcelo_malara
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Re: Gun range for 8' British cruiser guns?

Post by marcelo_malara »

So, it would be:

Angle of Departure (deg) 65
Range (yds) 26458
Striking Velocity (ft/sec) 1346
Angle of Fall (deg) 73.80
Time of Flight (seconds) 114.6
Maximum Ordinate (feet) 52106

Regarding Exeter´s guns, I think that Kevin is trying to evaluate visually the angle of elevation? That´s tricky, angles tend to be difficult to asses just by sight.
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Re: Gun range for 8' British cruiser guns?

Post by Kev D »

Bill Jurens wrote: Wed Oct 13, 2021 4:36 pmI am wondering what this information might be used for, as refinements might be made if the variables that are of most immediate relevance were known.
Bill Jurens
Hi Bill (and Marcelo),

First, thanks for your input!

Re your above, if you look at below, you will see what I am ballpark trying to achieve. Captain Gordon's "chart" for enemy positions at 1055am is on right, my 'modified' version given the main gun angles (as found on wreck) is to the southern group of cruisers, whom I believe they were firing at at 1120am when the fatal shell came in, is on left. So am just trying to get a ballpark range to those southern cruisers for my 1120am 'chart' using the gun elevation angle. I realise I can guestimate it from the range Captain Gordon gives at 1055, but....................thought I'd see what the experts said. :wink:

Kevin D
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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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Re: Gun range for 8' British cruiser guns?

Post by marcelo_malara »

If am not wrong, that shell passed thru an AA gun mounting before entering machinery room?
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Re: Gun range for 8' British cruiser guns?

Post by Kev D »

marcelo_malara wrote: Wed Oct 13, 2021 5:24 pm If am not wrong, that shell passed thru an AA gun mounting before entering machinery room?
No Marcelo, that was the hit on afternoon of 27th. Came in through the Stbd rear DP twin gun mount, killing all the crew of one gun only, and then on into the machinery spaces where it killed some more, knocking much of her power plant off-line in the process.

Nothing really as positive IIRC re location of hit on 1st, but from talking to survivors / veterans, it also hit on Stbd side just aft of bridge superstructure and before fore-funnel itself, and this time knocked out all power.
Last edited by Kev D on Wed Oct 13, 2021 6:33 pm, edited 1 time in total.
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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Re: Gun range for 8' British cruiser guns?

Post by Steve Crandell »

Don't gun elevations on a wreck reflect their elevation angle when the ship sank, i.e. when she was listing heavily and the guns were elevating to compensate for the list and the range to the target?
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Re: Gun range for 8' British cruiser guns?

Post by Kev D »

Steve Crandell wrote: Wed Oct 13, 2021 6:31 pm Don't gun elevations on a wreck reflect their elevation angle when the ship sank, i.e. when she was listing heavily and the guns were elevating to compensate for the list and the range to the target?
Yes often the case Steve, but with Exeter no time. She was engaging tne enemy and going the clackers (well supposedly 25 / 26 knots by then) and on an even keel when hit. And all power went out immediatley shell hit, and more were bracketing. And abandon ship was ordered very soon after the hit. There was no effort whatsoever to save her, as a matter of fact the opposite by opening seacocks and setting det charges. So all guns were left 'stuck' at whatever angle, both elevation and direction wise they were pointing at that exact moment the hit hit, or so the story goes.
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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Re: Gun range for 8' British cruiser guns?

Post by marcelo_malara »

Are there photos of the wreck showing the guns?

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Re: Gun range for 8' British cruiser guns?

Post by Kev D »

marcelo_malara wrote: Wed Oct 13, 2021 7:56 pm Are there photos of the wreck showing the guns? Regards
Yes and, well, yes, more or less.

That is, yes for the two Port secondary DP, the octuple 40mm, and quad .50 (both Stbd DP, .50 and most of 40mm buried in seabed / seabed build-up on that side of wreck). And 'not really' for the 8" except some video grabs in not so great visibilty, but main gun elevations and turret angles of train can be made out / ascertained. When I am at my computer again (on tablet at present) I'll see what I can dig out (although am moving house at present, literally, and just about to deconstruct my office tomorrow, so pics might not be till next week :? ). For main guns though, rear 8" basically at max elevation, both forwards down for reloading, all three trained off to the Stbd quarter.

Or I should say 'were', as wreck no longer there! :kaput:
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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