PoW secondary 5.25inch - 133mm guns at DS

[Antonio Bonomi]

Hello everybody,

it is time to open a thread about this subject, so who wants to deeply analyze it can do it with the right reference base.

Here an useful forum to refer to for the overall gun knowledge :

http://warships1discussionboards.yuku.c ... 7Lbob5H7s1

Here a movie to refer to ( from the above link ) were everyone can see the guns in action and their ROF ( rate of fire ) from min 1.50 until min 2.15 :

http://www.britishpathe.com/video/home-fleet-at-sea

Following the 2 main statements regarding the utilization at Denmark Strait of those guns by the HMS Prince of Wales.

From Capt J.C. Leach narrative :

"Hood" had a further 2 blue flying when, at 06.00, just after "Bismarck's" 5th salvo, a huge explosion occurred between "Hood's" after funnel and mainmast and she sank in three or four minutes.
"Hood" had fired five or six salvos but fall of shot was not seen, possibly because this coincided with firing of "Prince of Wales'" guns.
"Prince of Wales" starboard 5.25" battery was now in action.
Course had to be altered to starboard to avoid remains of "Hood"; meanwhile "Bismarck" had shifted main and secondary armament fire quickly and accurately onto "Prince of Wales".
A heavy hit was felt almost immediately.
And at 0602 compass platform was hit and majority of personnel killed. Navigating Officer was wounded; Commanding Officer unhurt.
The same salvo severed all fire control leads to the port forward H.A. Director and put the starboard forward H.A. Director out of action temporarily jamming it in training.

From PoW gunnery report :

7. The 5.25-in. armament opened fire at a range of 18,600 yards.
After firing a deflection triple, a 15-in. shell passed through the superstructure supporting the H.A. directors.
The shot caused the director to jam temporarily in training and the Control Officer of the latter ordered all turrets to go into "aft control".
This was carried out, but about the same time a 15-in. shell burst on the boat deck and seriously upset the after starboard H.A. director.
The crew of this director had already been considerably blasted by "Y" turret firing on a forward bearing.
The 15-in. shell burst threw the Control Officer off his feet, broke his telephone lead, and a splinter hit his earphones and very slightly wounded him.
By the time he had regained control of the situation, the target was lost behind smoke astern.
A careful inquiry has been held into the reason why the fore H.A. director jammed and no satisfactory explanation has been arrived at; the director was found to be "free" after the action and it is possible that the locking bolt jumped down and the Control Officer was too hasty in ordering "after control."
This fact has not, however, been proved and it is also possible that the severe shaking the director had caused it to "bind" temporarily in training.

Bye Antonio

[Steve Crandell]

As far as I can see, the respective secondary batteries were ineffective in this engagement. They were close to the limit of the ability to spot splashes effectively and some they might have otherwise seen were probably hidden by heavy shell splashes.

I think the British secondary directors were severely handicapped by being open to the elements, what with the concussion from the aft 14" guns firing on a forward bearing. Wind, rain, nearby hits and near misses would all have a deleterious effect on their efficiency.

German practice was to use a main battery director; usually the one above the conning tower. They don't seem to have hit anything either, though.

[Antonio Bonomi]

Hello everybody,

into Geoffrey Brooke book " ALARM STARBOARD " at page 56 you can read more about the 5.25 battery being in action for quite some time that morning.

Even if this book is not 100 % reliable about many battle events sequence and related timing, ... it is another available witness report.

Bye Antonio

[dunmunro]

A deflection triple was 3 rapid salvos fired to establish the correct line for the target. The options would be 3 rapid half salvos (4 rounds each) or 3 rapid full salvos of 8 rounds each so time to fire was on the order of 15 sec - 45 seconds.

[Antonio Bonomi]

Hello everybody,

@ Dunmunro,

thanks Duncan, ... that is a very important input to have.

So, here again we have another clear mismatch among various reported events.

If we assume being correct the opening fire reported into the PoW gunnery plot, ... than either the secondary did NOT fire ONLY the deflection triple ( PoW Gunnery report ) ... or both Capt. Leach and Geoffrey Brooke reported event/timing are NOT correct.

Similarly, assuming that it was the unavailability of the forward HACS directors the reason why they ceased fire ( reported both by Capt. Leach and PoW Gunnery report ) than we know the timing this event occurred, ... and it was well after 06.00, ... around/after 06.01 battle time, ... both for the forward as well as for the after ( crane + funnel + HACS hit ) directors.

Bye Antonio

[Antonio Bonomi]

Hello everybody,

here the layout of the PoW 5.25inches ( 133 mm ) secondary HACS directors.

PoW_HACS_directors.jpg (101.64 KiB) Viewed 4381 times

PoW_HACS_forward_directors.jpg (105.12 KiB) Viewed 4381 times

PoW_HACS_aft_directors.jpg (190.43 KiB) Viewed 4381 times

Bye Antonio

[Antonio Bonomi]

Hello everybody,

and here Tarrant description on how they were controlled.

Tarrant_PoW_Secondary_directors.jpg (111.78 KiB) Viewed 4380 times

So, FOUR ( 4 ) corners, ... 2 each side, ... 2 on port side ( fwd and aft ) and 2 on starboard side ( fwd and aft ).

Now Bismarck was on PoW starboard side ... which HACS director was damaged and by which shell ?

Here the list referencing above provided pictures :

1 - HACS director forward starboard side
2 - HACS director forward port side
3 - HACS director aft starboard side
4 - HACS director aft port side

Bye Antonio

[Alberto Virtuani]

"........After firing a deflection triple, a 15-in. shell passed through the superstructure supporting the H.A. directors........"

I think this is the key sentence. When you read it, it immediately leaves the impression that the 5.25" guns ONLY fired a deflection triple (as per Dunmunro post, max 45 seconds).
However, as the first assessment of the gunnery officers was that the hit in the fore directors support was a 15", it leaves NO doubts about this hit was received well after 6:00, with BS already having switched target and hit PoW.....
We know that this hit was in reality a 8", but the fact that the GAR states a possible 15" points to the 5.25" battery firing much more than a simple deflection triple.

Does anybody knows how we can get a report about the quantity of ammunition that was loaded on PoW after the actions on May 24 ? Where were the ship magazines replenished and when ? How many 5.25" shells and cartridges were taken on board

Bye, Alberto

[Antonio Bonomi]

Hello everybody,

@ Alberto,



... in fact if you refer to the Crane Hit Nr 3 thread, ... where I am analyzing the HACS declared OUT of ACTION sequence and their analysis by the PoW damage report ... there is a lot more to be discovered about what has been written ( or NOT written ) about the PoW secondary guns and their directors.

CUI PRODEST ? ... who took advantage of all this ?

Here an useful link about how the HACS worked :

http://www.navweaps.com/index_tech/tech-066.htm

Bye Antonio

[dunmunro]

Clift, Maurice William Mynard was an electrician stationed in the 5.25in transmitting station:

http://www.iwm.org.uk/collections/item/object/80008137 ( part 4, at ~24:00)

he places the HADT hit as happening before Hood was lost.

[Antonio Bonomi]

Hello everybody,

@ Dunmunro,

very interesting and thanks !!! ... this is a real help on researches ... let me just listen to it today and I will be back to you about it.

Bye Antonio

[Antonio Bonomi]

Hello everybody,

@ Dunmunro,

here is a quick extract of that interview :

Going out chasing the Bismarck ...rendez-vous with Hood across Greenland

Tell me as much details as much as you recollect the chase of the Bismarck

Jelly Cold at sea .. we were still working up …. Working up still doing gunnery exercise … …

We closed up at action station … my Action station being in charge of the weapon control … of the 5.25 turrets … the HA turrets

I was down at the forward transmitting station on the starboard side …. and than I had to kind of organize after both of those forward transmitting stations … port and starboard … when we closed up there …. By the way …

That particular transmitting station was down below 6 decks … well down below the waterline

We closed up and we knew that we were firing at the BS and PG … we had to go at the Prinz Eugen as well … we were firing at her …

All of a sudden we had been hit, … which made an effect to our gunnery … because it shot away our starboard director, …which was the rangefinder for the HA …. And …

All of a sudden … I am sitting down there, …. On the transmitting station … because the operators are all down there sitting by … a message came down from the bridge, …. the Hood has been hit …and within a few explanation … exclamation … a voice said “ she’ s gone, ... she’s gone, she’s disappeared .. .as quick as that … shes’s being sunk

We wanted to chase after … we were told by the admiralty ... as you know on the battle at sea ... against the Bismarck … we were certainly organized by the Admiralty … they told us to pull down at any action and to shadow her … that is exactly what we did, …we shadowed her … than we lost radar contact that night …

Admiralty told us to return to Rosyth because of our damage to our bridge, .... on the bridge the Captain was injured…. a famous man was blinded, and it was Esmond Knight on the bridge at the same time … … this was the blow of the Bismarck …on the bridge, .. when they shut at the directors

On the way back to Rosyth it was my job to repair those directors … the control of directors shot away by the pillar structure they on top ….electrical damage … control leads … port and starboard directors, … electric control of the circuits …down to the stations ….I had to go down there and organized the rewiring … max 8 core … organized a control party … hundreds of leads …. 36 leads colors, … 8 by 8 … 48 hours job … we worked right thru connecting every lead … we checked thru … fire control and rangefinders, … stop fire and cease fire and GONG’s … we did not wrong any connection … we checked it …and it worked perfectly ! I went to bed …and then the dockyard people came onboard and took photographs how did it work … and 24 hours after … they put the proper dockyard cables,…but they told that the temporary job was done perfectly.

What do you think about it Duncan ?

Bye Antonio

[Antonio Bonomi]

Hello everybody,

now that you have all the originals, I can publish this comparison about how the damages on the HACS directors have been reported on ADM 267/111 :

HACS director damages from POW damage report ADM 267/111

Hit Number 2

Damage description :

The H.A. support was distorted and the starboard H.A. director was jammed temporarily for training. There were no other mechanical failure.
Electric leads and junction boxes to the port director were severed (the leads were replaced by temporary wiring, rigged by ship’s staff, in little more than 24 hours).

Effect on Fighting Efficiency :

Port H.A. director out of action. Starboard H.A. director temporarily out of action.


Hit Number 3

Damage description :

Four splinters entered the port H.A. director and severely wounded one member of the crew.

Effect on Fighting Efficiency :

After H.A. director temporarily out of action.

Do you notice anything strange ?

Bye Antonio

[dunmunro]

Hello everybody,


What do you think about it Duncan ?

Bye Antonio

He has lots of interesting recollections including being on HMS Exeter during the Battle of the River Plate but the main point is that he placed the HADT hit as happening before Hood is lost.

[Antonio Bonomi]

Hello everybody,

@ Dunmunro,

YES, I have noticed that, ... but his recollection of the battle was only those 2 events, ... the first one involving himself personally after ... and the Hood explosion.

He does not recall anything else, ... no timings, ... no event sequences to rely on, .... no references, ... just those 2 things that were important for him ...

Than many errors, ... no shooting away of any director ... no firing at Prinz Eugen by PoW ... no messages from the Admiralty to stop fighting the Bismarck ...

Than he is associating the blow of Bismarck on the PoW bridge ... when they shut at the directors so, ... what was the correct sequence on his mind ....

I will keep this one of course among many other witness reports, ... but I do not considered it so definitive as I would have liked it to be for the moment .... since we still have stronger evidence of the events occurred on a different sequence than this guy was telling ...

Anyway, ... a very good input and right on the spot for the forward director port side cables, ... with related repair activities ... that was perfect.

What do you think about the PoW damage report above ?

You gave me a good interview to listen to, ... and I thank you for that, ... here is one for you now, ... pretty interesting indeed ...

http://www.iwm.org.uk/collections/item/object/80023587

... some errors as well ... but some very good inputs ... from a very important PoW position, ... the Plot Room !

NOTE : I have had in my hands the plot he was referring to ...

Bye Antonio