Question about RN & USN 6" Shells from WW2 compatib

[Iron Duke]

While chatting to a mate from this message board this very question arose. In the Pacific theater during WW2 were the 6" guns of the RN cruisers able to use the USN 6" shells and visa versa.
On the face of it both were 6" but I am sure there were differences between them. Was this enough to make them incompatable or not? Does anyone have any knowledge or thoughts on this? Thx in anticipation.

Like most things in life I am sure there is not a clear cut answer....

[Guest]

I'm surprised no one has grabbed this one yet...

The short answer is that they were not mutually compatible. This is perhaps even more attributable to the guns themselves, than to the shells. It only takes one variance between them to preclude cross-compatibility, and in most cases there were many variances.

Most naval guns of the period and the projectiles they fired were so thoroughly systemic, that introducing even a small change among their many parameters could throw everything out of whack.

Projectile dimensions and weights, gun barrel characteristics, breech configurations, and loading/handling of ordnance and propellants (just to name a few) were all critical factors.

For more detail on ordnance and lots of interesting stuff, visit:
http://www.navweaps.com (one of my favorite sites!)

Enjoy!

[Guest]

Yet the French 380mm guns on the Richelieu were able to fire British 15" (381mm) ammunition with just a very modest machining of the liners. The breech, chamber, and everything else seem to have caused no problem.

The French 15" guns on the Richelieu were the only ones to successfully employ a true all-angle loading system that really worked at all angles up to 45 degrees. Everyone else's all angle loading arrangement quit at about 20 degrees elevation because beyond that, the shell and powder would slide back out with the rammer before the breech could close. This is one reason why Hood's gun elevates up to 30 degrees but load only up to 20, and why everyone else but the French abandoned all angle loading once the gun elevation passed beyond 20 degrees or so. This suggests the French loading and breech mechanisms are quite unique.

[Michael Potter]

John Campbell wrote in Naval Weapons of WW2:

In 1943 when the Richelieu was refitted in New York, the four guns from Jean Bart's A turret were transferred to her as replacements and spares. The Richelieu's guns were re-bored to take British shell, apparently to 381mm (15.00in), though it had been determined before the war that the optimum for this shell was 14.985in (380.62mm).

A month or two ago someone (Richard Worth? ["Tiornu"]) wrote that a special outfit of about 400 shells was produced in the US for Richelieu. These events suggest that RN shells were never compatible with Richelieu's guns.

[ar]

There appears to a contradiction here, on its face.
If the guns were altered to take British shells, (and Campbell is very good), then why would there be the need to make a special batch? What source was used for the latter piece of data?

[Michael Potter]

Good question. I don't know tne answer. http://www.navweaps.com/Weapons/WNFR_15-45_m1935.htm modifies the mystery:

It is apparently untrue that Richelieu's guns were bored out to 15.0" (38.1 cm) during this time, as French records indicate that they remained at 380 mm (14.96"). Sometime after this refit, new AP and HE shells designed to meet French specifications were specially built for her by the Crucible Steel Company of America.

Even if the RN shells were compatible, it's conceivable that the RN did not have a surplus of 15-inch shell to offer, or simply that the US shells were practically free so why expend the effort to ship RN shell to the US.

[Seasick]

IIRC US manufacturers produced 15 inch shells for RN and French BB durring WW2.

Starting in 1958 the USA and the Commonwealth adopted the international inch which is defined as exactly 25.4 millimeters. Before the US inch was

UK Pre-1959 1 inch = 25.399956 mm
USA Pre-1959 1 inch = 25.400508 mm
1959 onward 1 inch = 25.4 mm

The difference is slight but for mechanical design with tight tolerances its very significant.

US and UK ordinance manufacture had both switched to metric before ww2.

[Ron Smith]

There appears to a contradiction here, on its face.
If the guns were altered to take British shells, (and Campbell is very good), then why would there be the need to make a special batch? What source was used for the latter piece of data?

Gee Alan, not all that hard to find at the source, NARA. No Alan, you cannot simply call them up and get copies anymore.

[Laurence Batchelor]

For Richelieu the ever questionable Whitley states her ammunition on being deployed to the British Eastern Fleet "could only come from US sources".
He does not quantify if this was only her AA or also her main armament shells as well.

He does state in bombardments between 27th April to 7th May 1945 she fired 133 rounds of 15-inch at targets in the Nicobar Islands which reading between the lines she would not have done if she could not obtain a ready supply of main armament shell.

Garzke & Dulin state the following for Richelieu whilst she was under refit in New York between February 1943 - August 1943 "380-mm guns were manufactured by the Crucible Steel Company of America to specifications of the French Navy" note they do NOT mention SHELLS were made, but Crucible merely made her GUN BARRELS! p94.

Thus I feel the USA dockyards merely copied the existing 380mm gun barrels she had onboard to give her all 8 barrels functioning properly. They do mention that most of the repairs they had to carry out to the rest of her damage and systems were 'custom parts'.

To blur the picture somwhat in a later caption to a photograph Garzke & Dulin state the following: "These two photos of the Richelieu in her wartime camouflage were taken while she was undergoing trials and training in Chesapeake Bay in September 1943. The main-battery guns were overhauled and replaced, and all the main-battery guns were rebored to 381mm to accept British shells of that calibre. Note that the 381-mm guns are mounted on seperate sleeves permitting individual firing" p96.
They fail to mention this data in their text or in Richelieu's characteristics post modernization table.

I suggest as soon as it was known that she would likely be deployed to the Eastern Fleet it was deemed necessary to carry out the later modifications to accept British shell which was done whilst she was undergoing this refit.

If you examine any Richelieu photograph and you see she has the seperate black sleeves for her barrels then this is after she had the modifications to accept to British shells.

I would check my detailed Richelieu book by Robert Dumas, but I can't read French!

[Guest]

Garzke & Dulin state the following for Richelieu whilst she was under refit in New York between February 1943 - August 1943 "380-mm guns were manufactured by the Crucible Steel Company of America to specifications of the French Navy" note they do NOT mention SHELLS were made, but Crucible merely made her GUN BARRELS! p94.

I find this impossible to believe. The process of manufacturing battleship a gun barrel takes 2-3 years from start to finish. If a battleship and her guns are ordered at the same time, then the length of time it takes to make her guns controls the tempo at which a new battleship can be built. It is impossible for the US to have made replica barrels for the Richelieu by 1943 unless they begun in 1940.

-CHuck

[Iron Duke]

[quote="Anonymous"]I'm surprised no one has grabbed this one yet...

The short answer is that they were not mutually compatible. This is perhaps even more attributable to the guns themselves, than to the shells. It only takes one variance between them to preclude cross-compatibility, and in most cases there were many variances.

If this was the case, in WW2 then the RAN & RNZN must have had real issues to get supplies of shells for use in their cruisers and other vessels from half way around the world in wartime and the related shortages of everything. I am not aware of the Australians producing their own shells. I know the Kiwi's definitely did not.
Like to see if anyone has more information. May be a question to ask the RAN & RNZN museums.

[ar]

What does Dumas say?

[Laurence Batchelor]

I find this impossible to believe. The process of manufacturing battleship a gun barrel takes 2-3 years from start to finish. If a battleship and her guns are ordered at the same time, then the length of time it takes to make her guns controls the tempo at which a new battleship can be built. It is impossible for the US to have made replica barrels for the Richelieu by 1943 unless they begun in 1940.

-CHuck

My apologies I deleted something from the qoute and made it erronous.
For "380-mm guns were manufactured by the Crucible Steel Company of America to specifications of the French Navy"
Should read "Shells for the 380-mm guns were manufactured by the Crucible Steel Company of America to specifications of the French Navy"

Further 2 barrels were taken from Jean Bart to replace damaged ones in turret II.
I really should get some sleep

What does Dumas say?

You evil man you don't you know I have work to do!
If I must.....I've got the book out I'll scan where the refit might be detailed and I'll try and translate the text for all to read.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Examined Dumas and could find no mention of the above, although I consider looking for english key words throughout this book a flawed thing to do.

It does state this on p37 which appears is where the USA refit is detailed:

"Armament - principal Artillery: three parts (5-7-8) of turret II are remplaced by cellespreIevees on the Jean Bart! (I). Braies of sealing protegent the embrasures of the turrets. - secondary Artillery: the armatures of the conver�tisseurs are remade. All defective electric wiring is exchange. Moreover, important work concerns the installations of supply of these two artilleries. - Artillery of D.e.A. rapprochee: it is in this field that the change is most important. Certain superstructures of the armour are modifiees to allow the installation of 14 quadruple mountings of 40 mm Bofors and 50 simple mountings of 20 mm OerIikon. ~ Sites of the affiits of 40: 2 mountings on both sides of turret II of 380; 2 mountings on the bridge castle on both sides of the blockhouse; 2 mountings?. on both sides of the footbridge of navigation and below t.d' el1e; 2 mountings on the bridge passerel1e, on both sides of the!Cheminee; 2 mountings on the bridge castle, in the transverse axis rclu telepointor B of principal artillery et4 mountings on the beach!jrdere."

As one can see Babaelfish online translation tool struggles with technical French text. He confirms she had 2 barrels from Jean Bart, but I could find no mention of reboring to accept British 15" shells or if French shells were made in the USA.
I'm surprised as this book is very detailed at some 128 pages on her including every conceiable thing drawn in plan form.

[warspite63]

Hello, all.

Sorry I can't remember where I read it (possibly a thread on the excellent Warships1.com forum). but apparently the re-boring from 380mm to 381mm never took place. I find this easy to believe in light of the fact that the US was able to make ammo for the 100mm guns (as well as the 152mm guns?) - making 380mm ammo would surely be simpler than re-boring the main battery guns. Not to mention the fact that this would have left the post-war Marine Nationale with 2 BB's, each of which had a main battery whose calibre differed by 1mm, as Jean Bart got Clemenceau's guns.!

[Guest]

Actually, Jean Bart's main battery was never made entirely operational. Only one of the 2 turrets were made fully serviceable. The other one was mothballed incomplete (Although fireable). The main armament fire control was also never completed to the degree that would have rendered it capable of a sea engagement. So the often repeated claim that Jean Bart was last battleship in the world to be completed in 1955 is not entirely accurate. She was never entirely completed.

[RoddersUK]

Well guest, your comments are an eye opener. I presume your statement comes from knowledge, though it does not surprise me.
The French are renowned for their style. Engineering wise is one of the reasons why they never ever defeated the British. They just aint got it.
Where the rest of the world will accept certain engineering parameters and produce products to these parameters the French will not. The French have to produce their own products to a French design. The fact that their designs are below normal standards as compared to the Japanese, the Germans, the British or the Americans seems to escape them. The French will do nothing for themselves or the world unless there is something in it for France.