16"/45 Mark 6 Turrets face is Class A or Class B?

[ssvcrtfi]

16"/45 Mark 6 Turrets face is Class A or Class B?

[TopHatter]

16"/45 Mark 6 Turrets face is Class A or Class B?

Class B

Armor Schemes on W.W.II Battleships

[ssvcrtfi]

Class B

Armor Schemes on W.W.II Battleships

Thank you

[Tiornu]

The issue is unclear regarding Washington and North Carolina. The decision to switch to Class B was made around that time, but may have applied only to later ships. The switch to Class B was linked very specificially to an increase in the thickness of the faceplate armor in the SoDak class, but I know of no indication of a thickening in the NC class.

[ssvcrtfi]

The issue is unclear regarding Washington and North Carolina. The decision to switch to Class B was made around that time, but may have applied only to later ships. The switch to Class B was linked very specificially to an increase in the thickness of the faceplate armor in the SoDak class, but I know of no indication of a thickening in the NC class.

NC Class's Turret face is Class A?

[Tiornu]

The decision to use Class B for the SoDak faceplates was officially made on 20 Jan 1940. This would seem a little late for NC, but then, I can't say a separate order for NC did not come earlier. It seems unlikely, however. I don't think NC had Class B faceplates, but it is not certain.

[RustyBattleship]

Since the turrets are usually facing the enemy, it was discovered that the turret face was more likely to get a direct hit with little or no obliquity of the incoming shell. I think an Italian BB found this out the hard way and its face hardened turret plate shattered like glass.

Class B armor doesn't have the brittleness, yet it is still tough but has to be thicker. Class A armor was set in places or structures where the incoming would be at an extreme enough angle to break up or deflect the shell casing.

If we were to design a new Battleship today, in all likelyhood no Class A armor would be designed into it as large caliber high velocity artillery shells are not our worry anymore. But where you need thick steel Class B (or an equivilant to it) would be chosen. It's cheaper too as its manufacture skips past the face hardening steps that are long, tedious and subject to delamination if quenching is not done correctly.

[ssvcrtfi]

Is there any relevant information ？thanks！

[Tiornu]

I think an Italian BB found this out the hard way and its face hardened turret plate shattered like glass.

Maybe you're thinking of a French ship. No Italian battleships suffered any turret penetrations.

[RustyBattleship]

Maybe you're thinking of a French ship. No Italian battleships suffered any turret penetrations.

Could have been French. The information was given to me by an armor and artillery shell expert from Port Hueneme back in 1981.

[Tiornu]

I think this is the incident you have in mind. During the British attack on the French at Mers el-Kebir in 1940, a 15in shell struck the battleship Dunkerque on the forward angled portion of the turret roof. The armor, designed with German 28cm shells in mind, was somewhat overmatched by the British shell weighing more than twice at much. Even so, the angle of the hit might have caused a relatively harmless ricochet if not for the French decision to use face-hardened armor in the turret roofs. The 15in shell did not penetrate, but the brittle face of the armor allowed the impact to scrape a notch through the plate. Bits of shell and broken armor went shooting into the gunhouse interior, striking crewmen and exposed powder. The entire crew on that side of the gunhouse were killed by the fragments and asphyxiation.
The Japanese were the only others to fit face-hardened armor on their turret roofs. I suspect this would have had a negative effect in the event of a duel with American ships, equipped with shells that were especially rough on horizontal armor.
I think I can scan a photo of the Dunkerque hit, if anyone wants a peek.

[Dreadnought]

I think this is the incident you have in mind. During the British attack on the French at Mers el-Kebir in 1940, a 15in shell struck the battleship Dunkerque on the forward angled portion of the turret roof. The armor, designed with German 28cm shells in mind, was somewhat overmatched by the British shell weighing more than twice at much. Even so, the angle of the hit might have caused a relatively harmless ricochet if not for the French decision to use face-hardened armor in the turret roofs. The 15in shell did not penetrate, but the brittle face of the armor allowed the impact to scrape a notch through the plate. Bits of shell and broken armor went shooting into the gunhouse interior, striking crewmen and exposed powder. The entire crew on that side of the gunhouse were killed by the fragments and asphyxiation.
The Japanese were the only others to fit face-hardened armor on their turret roofs. I suspect this would have had a negative effect in the event of a duel with American ships, equipped with shells that were especially rough on horizontal armor.
I think I can scan a photo of the Dunkerque hit, if anyone wants a peek.

*The turret roofs being more lightly armored then other portions of the turret such as face,rear sides was the norm for battleship design as any shot coming in hitting the turret would indeed ricochet of the roof due to the mathematical arc that gunfire follows. There have been cases in the IJN where the turret roof was peeled open like a can but they cannot subscribe this to a turret hit from gunfire but more likely an aerial dropped bomb since no records existed of the hit that peeled the turret open.

[lundgrenr]

Ise

Ise when she was bombed at Kure had two turret roofs holed by HC bombs near the sight hoods. Though the bombs were rejected the impact successfully punched out an armored plug through the roof which was 6-inch thick. I believe it was turret three and turret one. Both turrets were knocked out of commission. I have their full damage reports at home. These are the only two battleship main battery gun turrets that I know of that suffered a roof hit of any kind. If there were others I would be interested in finding out.

I have questioned if the older class ships used VC plates for the roof because the photos show many bolts in the armor. You should not bolt through the hard face to my knowledge without ruining the face of the plate. If it was done somehow it would prove to be a weak spot in the armor. The Japanese technical mission which the damage report comes from specifically says NC or non-cemented. Other Japanese sources say VC or Vickers cemented. It would make more sense if a plug was punched out if they used VC especially to a HC bomb that exploded on impact.

[Dreadnought]

I would have to check on either Morgami or her sister Mikuma as they have suffered from an aerial dropped bomb in the turrets as well days after the retreat from Midway.

[Tiornu]

The Mogamis have just an inch of armor on their gunhouses, so there won't be much to learn from them.