Triple and quatruple turrets

[Thorsten Wahl]

according
Unterlagen und Richtlinien zur Bestimmung der Hauptkampfentfernung und der Geschoßwahl Heft h Schlachtschiffe Bismarck und Tripitz 1940
for 25 km distance ( target height 10 m and -width 30m)
hit probability for MPI on target should be 15,5%
or 2,5 hits per minute out of 16 shots

in 1941 ther was a program for reducing dispersal using
1)projectiles of only one weight class (only +-0,5% weight deviation allowed for all projectiles on a ship)
2) same absolute state of powder charges - allowing for any combination of all fore and rear charges on board
how far the probabilities have been changed by these measures I dont know.

[alecsandros]

Thorsten,
The 15.5% percent hits is against moving or stationery target ?

Hessen was a smaller target, with 6m freeboard and 22m width at the maximum.

[Thorsten Wahl]

moving target -broadside

[alecsandros]

moving target -broadside

Those appear to be excellent results.

Any more info on target speed perhaps ?

[alecsandros]

I've done some digging, in order to compare the figures with US Navy firing trials.

I found 2 interesting trials:

1) 1935 USN exercise, with 13 battleships firing simultaneously on a battle raft.
Range: 17000y, fire with reduced charges. Simulated range: 27450 yards
Target: 520 sq. feet battle raft, moving at 20kts.
Shooting conditions: not ideal.

Findings: 60 hits out of 1179 shells fired.
Extrapolating the battle raft size to battleship size, the conclusions indicated that "3.3 hits/minute/ship" might be expected. [a very good result ]

2) 1940 USN exercise,
Several battleships attacked independently a battle raft, simulating a 785ft battleship, moving at 20kts, 19000y distance.

Shooting conditions were bad throughout, and several 30* changes of course (as imposed by the exercise) made things even worse.

However, average performance was 1 hit/minute/ship, with several battleships doing better...

[Ersatz Yorck]

Does anyone know what the normal salvo size was for the German nine-gunned ships (S&G). Did they fire three guns to a salvo, and if so, one turret or one gun from each turret? How about the Deutschland class, did they normally fire one turret to a salvo?

[tommy303]

normally salvo fire was three guns by turret salvos.

[Ersatz Yorck]

Thanks! That is interesting! In comparison, the Austrians in WW1 apparently fired one gun per turret in each salvo with the Tegetthof class.

But isn't three rounds too few for good spotting, given that some shells might be outliers? I have gathered that four rounds is optimal?

[tommy303]

Three was considered the useful minimum. In general terms, turret salvos were preferred to firing one gun from each turret, as in the Austrian example you gave; the main reason was less need to calculate convergence, and the hoists in a turret normally operated together rather than independently as in British turrets.

[Ersatz Yorck]

But in WW1 it seems that one gun per turret per salvo was the standard practice. From Campbell's Jutland for example it is clear that this was the most common method of firing both for Germans and British. While turret group salvoes did occur, it seems they were the exception rather than the norm. See this picture of the König at Jutland, clearly firing one gun per turret while the other is in the reload position.

While a painting, the artist, Claus Bergen, accompanied the HSF on exercises because the Kaiser wanted nice accurate paintings of the Jutland battle, so the paintings are likely to depict real practice.

König at Jutland by Claus Bergen.

KonigJutland.JPG (73.4 KiB) Viewed 4516 times

[Dave Saxton]

At North Cape during the stern chase segment, Scharnhorst settled into firing 6 gun salvoes. It would quickly jink to the south unmasking Bruno and then fire a six gun salvo togeher with Ceaser and then return to its escape course toward the east. It was only firing intermitantly this way, however. Previous to Bruno being brought back on line it only had C turret available. It seems to have been firing all guns in each turret together through out, though. Against Glorious Scharnhorst and Gneisenau are firing all three guns in each turret. In the famous frame of Scharnhorst opening fire at 26,000 meters, it appears that Scharnhorst fires all six guns from Anton and Bruno together. Or do others see it different?

[tommy303]

But in WW1 it seems that one gun per turret per salvo was the standard practice.

Yes indeed. However post war in the Reichsmarine (later Kriegsmarine) this was done away with to simplify procedures within the turrets and to improve safety by reducing the number of cartridges in transport between handling room and gun house (with the older method of firing half the guns in the turret, while the other reloaded, there was always a set of charges in transport). I should add it was also easier to reduce the size of the salvo pattern with turret or turret group salvos which made spotting easier.

As to the action against Glorious, there are some photos or stills from film showing turret salvos. Often turret salvos with the triples or turret groups with twins might be used until range was found and target acquired, then broadsides or simultaneous salvos employed to finish off the target.

[tommy303]

I do seem to recall that Luetzow or Derfflinger fired by turret groups at Jutland, but it has been a while since I have read the accounts and need to check.

[Byron Angel]

I do seem to recall that Luetzow or Derfflinger fired by turret groups at Jutland, but it has been a while since I have read the accounts and need to check.

Quite so. Lutzow did indeed conduct its fire by fore and aft turret groups - the four gun salvoes from A & B turrets alternating with the four gun salvoes from C and D turrets. IIRC, an eight-shot broadside was also fired during the action, but not repeated due to spotting difficulties.

B

[Ersatz Yorck]

Quoted from Campbell:

With the exception of the Lutzow, the German ships fired APC shell with salvos of one gun per turret, but the flagship fired her four forward and four after guns alternately and used uncapped semi-AP. One full salvo was tried but it fell mostly short, obscuring the Lion with its numerous water columns. The British ships fired salvos of one gun per turret, and the 13.5in ships all used APC. The New Zealand apparently began with CPC, but on straddling changed to nose-fuzed HE.

IIRC von Hase of the Derfflinger does not mention firing by turret groups but it was some while since I read it. I do remember he mentioned ships of the Queen Elizabeth class firing full 8 gun salvoes at one point. Edit: I just had to check. von Hase clearly states he was firing one gun from each turret to a salvo.

At a guess, it might have been more logical to fire turret groups of 2 turrets and four guns from a ship with 4 double turrets, while in most of the earlier dreadnoughts with ten guns in five double turrets it might have been nearer to hand to fire one gun from each turret to a salvo. In a ship with triple turrets, turrets salvoes is even more logical.

I wonder what the practice was in a ship with 6 guns in three double turrets like the Renown and Repulse? I guess one gun from each turret to get three rounds to a salvo.