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fusing shells

Posted: Tue Dec 25, 2018 9:23 pm
by paul.mercer
Gentlemen,
How were shells kept in the shell rooms of ships?
I understand that they would have been kept in holders or containers until they were moved to the lift to the turret, but were they all kept ready fused or were the fuses inserted before the went up? What puzzles me is that some ships like Barham exploded as she rolled over which would suggest that all her shells were 'live'. So what was the procedure, as if they were surely there could always have been a danger of one breaking loose in heavy seas?

Re: fusing shells

Posted: Sat Jan 12, 2019 7:54 pm
by Dave Saxton
Tommy303 can give you much more detailed information.

Armor piercing units are screwed into the base of the main body like a bolt is screwed into something by wrench. They work by inertia, so when the shell encounters sufficient deceleration it goes off. The deceleration causes a firing pin to strike an explosive primer or the other way around. They are designed so it takes a short period of time before it will ignite the shell's explosive filler. Technically these are call Graze Action fuses. Fuses must be "permanently" installed in such cases. They are always "armed" as I understand it.

High Explosive shells and some semi armor piercing have a nose fuse. These are also percussive fuses. Since the shell strikes the target by the nose the firing pin is triggered by contact with the target. Technically these are called Direct Action fuses.

With either type a falling or tumbling shell could have its fuse could go off.

A bomb or a torpedo may need to have the fuse "armed" first before the firing pin or other actuator can work. This is is often done by some kind of a spinning motion. In the case of a torpedo it might have a small propeller that spins as the torpedo travels through the water. A bomb may use the same principle as it travels through the air.

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Re: fusing shells

Posted: Fri Jan 25, 2019 2:16 am
by tommy303
Sorry to have been so long away. During wartime, the shells were fuzed and ready for use. Normally this would not have been a major safety issue as the fuzes had built in safety devices which prevented the shell from arming.

Re: fusing shells

Posted: Sun Jan 27, 2019 12:21 am
by Byron Angel
tommy303 wrote:
Fri Jan 25, 2019 2:16 am
Sorry to have been so long away. During wartime, the shells were fuzed and ready for use. Normally this would not have been a major safety issue as the fuzes had built in safety devices which prevented the shell from arming.
A belated Happy New Year to you, Tommy - happy, healthy and prosperous.

Byron

Re: fusing shells

Posted: Mon Jan 28, 2019 10:52 am
by paul.mercer
Gentlemen,
As usual, many thanks for your replies, they explain why so many ships blew up as they rolled over. Looking at some pictures of 15" shells being hoisted aboard a QE class, I wonder what might have happened if one slipped out of its cradle and on to the deck or pier, big bang?