Explosion of shells

Guns, torpedoes, mines, bombs, missiles, ammunition, fire control, radars, and electronic warfare.
alecsandros
Senior Member
Posts: 3990
Joined: Wed Oct 14, 2009 2:33 pm
Location: Bucharest, Romania
Contact:

Explosion of shells

Postby alecsandros » Fri May 18, 2012 12:46 pm

Hello,

When heavy shells impact water, do they (usualy) explode shortly thereafter, or do they become duds ?

And, are the high columns of water created by the explosions of the shells, or simply by the high-velocity impact with the surface of the water ?

User avatar
marcelo_malara
Senior Member
Posts: 1072
Joined: Sun Oct 02, 2005 11:14 pm
Location: buenos aires

Re: Explosion of shells

Postby marcelo_malara » Fri May 18, 2012 1:44 pm

Yes, they explode, there are many instances of splinter damage from a nearby impact.

Regards

User avatar
RF
Senior Member
Posts: 7490
Joined: Wed Sep 20, 2006 1:15 pm
Location: Wolverhampton, ENGLAND

Re: Explosion of shells

Postby RF » Fri May 18, 2012 5:03 pm

As far as I am aware the surface tension in water would form a substantial obstacle to a shell and cause its detonation?
''Give me a Ping and one Ping only'' - Sean Connery.

User avatar
marcelo_malara
Senior Member
Posts: 1072
Joined: Sun Oct 02, 2005 11:14 pm
Location: buenos aires

Re: Explosion of shells

Postby marcelo_malara » Fri May 18, 2012 5:51 pm

That´s right Robert, an object striking the water at 500 m/s is almost the same as striking earth or rock, people falling to the water from 50 m height can die.

User avatar
tommy303
Senior Member
Posts: 1526
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Re: Explosion of shells

Postby tommy303 » Tue May 22, 2012 7:55 pm

When heavy shells impact water, do they (usualy) explode shortly thereafter, or do they become duds ?

And, are the high columns of water created by the explosions of the shells, or simply by the high-velocity impact with the surface of the water ?


Water will certainly provide sufficient check to a base fuzed shell to initiate fuze action, and unless something goes wrong with the fuze, detonation will occur at the end of the designed delay period. Nose fuzed shells will detonate almost instantaneiously. Things can of course go wrong, as there are very considerable stresses involved with water impacts.

The water column thrown up an impacting projectile is pretty much from kinetic energy rather than the explosion of the shell. AP shells, which have both small explosive charges and a fuze delay create much higher splashes than nose fuzed shells which detonate on impact. In the later case, the explosion of the shell's payload tends to disrupt the full formation of a normal shell splash.

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

User avatar
Gary
Senior Member
Posts: 706
Joined: Mon Apr 17, 2006 3:37 pm
Location: Northumberland

Re: Explosion of shells

Postby Gary » Thu May 24, 2012 10:10 pm

At Dogger Bank, Seydlitz clocked Lion with a hit that ricocheted off the water and pierced the 5 inch aft armour but the shell failed to explode suggesting that this was a defective shell.
This was the hit that caused Lion Dynamo's to become flooded
God created the world in 6 days.........and on the 7th day he built the Scharnhorst

User avatar
RF
Senior Member
Posts: 7490
Joined: Wed Sep 20, 2006 1:15 pm
Location: Wolverhampton, ENGLAND

Re: Explosion of shells

Postby RF » Fri May 25, 2012 5:54 pm

Talking of richochets, I am reminded of the tale once mentioned by Barnes Wallis about Nelson - how he used his cannon fire to deliver ''yorkers'' because the force of richochet gave the cannonball much more impact power.

Before anyone asks - as any English member of the forum should know, a yorker is a delivery in cricket bowled at the batsmens feet to take out the base of the cricket stumps, uprooting them out of the ground and sending them cartwheeling past the wicket keeper. In the case of Nelson we are talking of the target ships' waterline as the base of the cricket stump.
''Give me a Ping and one Ping only'' - Sean Connery.

User avatar
tommy303
Senior Member
Posts: 1526
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Re: Explosion of shells

Postby tommy303 » Fri May 25, 2012 7:57 pm

A direct shot against an enemy vessel's hull would normally result in a fairly neat, easily plugged hole due to the relatively high velocity of a usual 24---36-pdr broadside guns of the old sailing era line of battle ships. Skipping a round across the water rapidly reduced the velocity (and made a waterline hit easier to achieve) to a point where the large, slow moving iron shot would tend to smash through planking and frames and making much larger, more jagged holes (somewhat like the low velocity carronade).

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

lwd
Senior Member
Posts: 3810
Joined: Sat Jun 17, 2006 2:15 am
Location: Southfield, USA

Re: Explosion of shells

Postby lwd » Tue Jun 19, 2012 11:56 pm

I doubt that they would loose a lot of energy skipping off the water. From seeing a cannonbal hit the ground and roll along it and from skipping rocks off the water this just doesn't fit. What might occure though is for some of the energy to be converted to rotational energy so when it hits the opposing ship it tends to have enough spin to react more with the components there of.

User avatar
tommy303
Senior Member
Posts: 1526
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Re: Explosion of shells

Postby tommy303 » Mon Jun 25, 2012 7:19 pm

I seem to recall, that in the case of projectiles, be it a stone or cannon ball, each successive ricochet off water is half the distance of the previous bounce, and this would indicate a rapid falling off of velocity.

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

Byron Angel
Senior Member
Posts: 730
Joined: Sun Mar 06, 2011 1:06 am

Re: Explosion of shells

Postby Byron Angel » Tue Jun 26, 2012 2:47 am

tommy303 wrote:I seem to recall, that in the case of projectiles, be it a stone or cannon ball, each successive ricochet off water is half the distance of the previous bounce, and this would indicate a rapid falling off of velocity.





..... A great deal would depend upon what range would see the first strike of the ball. Boudriot ("The 74 Gun Ship") IIRC wrote that such ricochet fire was considered in French naval gunnery service top be reasonably effective out to 900 meters. In any case, a more modest striking velocity would trend toward an awkwardly shaped hole with a great deal of peripheral splintering, whereas a hit at great velocity would tend to result in a round easily stoppered hole with minimal splintering effect.

B

User avatar
tommy303
Senior Member
Posts: 1526
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Re: Explosion of shells

Postby tommy303 » Tue Jun 26, 2012 4:57 am

Exactly. At closer ranges it was more effective to double shot the guns which both lowered the muzzle velocity and doubled the number projectiles.

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

User avatar
Rick Rather
Member
Posts: 139
Joined: Sun Nov 06, 2011 4:15 am
Location: Dallas, Texas USA

Re: Explosion of shells

Postby Rick Rather » Tue Jun 26, 2012 6:15 am

I recall seeing 5" projectiles ricochetting off the water. They were fired by a Mk42 5"54 mounted on a Belknap-class CG. Elevation was close to horizontal. The first splash was several k-yards out, and second splash appeared near the horizon (I was standing on the first deck, <20 off the water). Obviously the rounds were non-explosive. The splashes were tall, thin columns of white water. I am guessing, but I believe these towers were actually the secondary splash caused when the water rushed back in to fill the hole left by the initial impacts, which displaced most of the water horizontally. Either that or recoil from the impact against an incompressable medium. As I said, I observed the effect, but am guessing at the cause.
Just because it's stupid, futile and doomed to failure, that doesn't mean some officer won't try it.
-- R. Rather

lwd
Senior Member
Posts: 3810
Joined: Sat Jun 17, 2006 2:15 am
Location: Southfield, USA

Re: Explosion of shells

Postby lwd » Tue Jun 26, 2012 7:51 pm

tommy303 wrote:I seem to recall, that in the case of projectiles, be it a stone or cannon ball, each successive ricochet off water is half the distance of the previous bounce, and this would indicate a rapid falling off of velocity.

I was curious about this and after a quick search found:
http://arxiv.org/pdf/physics/0210015v1.pdf
on page 5 it states:
The important point to note is that the energy loss during one collision, Eq. (17), is independent of the velocity Vx0 before the collision.

Which would suggest that a halving relationship is not characteristic of such collisons.

paul.mercer
Senior Member
Posts: 569
Joined: Fri Mar 26, 2010 10:25 pm

Re: Explosion of shells

Postby paul.mercer » Tue Jun 26, 2012 8:04 pm

Gentlemen,
Thre have been reports of ships firing their heavy guns into the water against low flying aircraft, presumably trying to get the splash to bring them down, if this is true, would those shells have exploded or just skipped accross the water like a stone on a pond due to the low angle at which they were fired?


Return to “Naval Weapons”

Who is online

Users browsing this forum: No registered users and 1 guest