Shell hits
Re: Shell hits
Occasionally ready service ammunition will be set off.
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Byron Angel
Re: Shell hits
Hi alecsandros,
I ran the US 16in 2,240lb AP projectile (2550 fps MV) and arrived at the following results -
range - 8,090 yds
angle of fall - 4.5 degrees
striking velocity - 2,097 fps
At this range and conditions, this projectile (at 2,240 lbs including cap and screen) requires 2,097 fps to cleanly penetrate 1.6 inches of Japanese NVNC deck armor.
If the projectile were to first pass through 6in KC WW1-era vertical plate with line of fire at approx 35 deg to target centerline, it would achieve complete penetration by an intact projectile, but losing AP cap and windscreen in the process. Upon exit from the vertical plate, the projectile weight would be 1969 lbs with a remaining velocity of 1,740 fps. Based upon this, I would venture that this particular projectile would have failed to penetrate an armored deck of equivalent 1.75 inches thickness.
The US 2,700 lb 16in projectile COULD penetrate the armored deck in question at approx 8,000 yards, but not if it had to pass through 6in vertical plate first (if I am interpreting the results correctly).
Also, consider this - at an angle of fall of 4.5 degrees, a projectile passing through a vertical plate four feet above deck would only strike the deck after travelling about 50 ft. If the vertical plate were of armor thick enough to have initiated the fuse, the projectile would have been at or extremely close to the deck when it exploded.
BRgds / Byron
I ran the US 16in 2,240lb AP projectile (2550 fps MV) and arrived at the following results -
range - 8,090 yds
angle of fall - 4.5 degrees
striking velocity - 2,097 fps
At this range and conditions, this projectile (at 2,240 lbs including cap and screen) requires 2,097 fps to cleanly penetrate 1.6 inches of Japanese NVNC deck armor.
If the projectile were to first pass through 6in KC WW1-era vertical plate with line of fire at approx 35 deg to target centerline, it would achieve complete penetration by an intact projectile, but losing AP cap and windscreen in the process. Upon exit from the vertical plate, the projectile weight would be 1969 lbs with a remaining velocity of 1,740 fps. Based upon this, I would venture that this particular projectile would have failed to penetrate an armored deck of equivalent 1.75 inches thickness.
The US 2,700 lb 16in projectile COULD penetrate the armored deck in question at approx 8,000 yards, but not if it had to pass through 6in vertical plate first (if I am interpreting the results correctly).
Also, consider this - at an angle of fall of 4.5 degrees, a projectile passing through a vertical plate four feet above deck would only strike the deck after travelling about 50 ft. If the vertical plate were of armor thick enough to have initiated the fuse, the projectile would have been at or extremely close to the deck when it exploded.
BRgds / Byron
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alecsandros
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Re: Shell hits
From the way I understand Lundgren's paper and the drawing inside it, it appears that the alleged explosions occured on the upper deck. If this is true, than there woudl be no prior vertical armor penetration.
The shells used, for what I know, were 16"-2700pds mark8's, which had an angle of fall of 5.4* at 8000y.
If facehard.exe is to be used, we get:
exit velocity - 1764ft/s, projectile reamining body-weight 2352.5pds.
Then, with M79APCLC.exe, we have the shell clearly piercing 1.6" of Japanese H-armor, at 5.4* fall... Exit velocity 1749ft/s...
Indeed, if the fuse were activated on impact with the vertical armor, the shell would have traveled some distance before exploding. If we take a 0.030 - 0.040 interval of the fuse, and 1764ft/s exit velocity, the shell would travel 53 - 70.5 ft before exploding. That would be 15-20 meters... Inside the ship...
The shells used, for what I know, were 16"-2700pds mark8's, which had an angle of fall of 5.4* at 8000y.
If facehard.exe is to be used, we get:
exit velocity - 1764ft/s, projectile reamining body-weight 2352.5pds.
Then, with M79APCLC.exe, we have the shell clearly piercing 1.6" of Japanese H-armor, at 5.4* fall... Exit velocity 1749ft/s...
Indeed, if the fuse were activated on impact with the vertical armor, the shell would have traveled some distance before exploding. If we take a 0.030 - 0.040 interval of the fuse, and 1764ft/s exit velocity, the shell would travel 53 - 70.5 ft before exploding. That would be 15-20 meters... Inside the ship...
Re: Shell hits
I believe it's possible for a shell to detonate on contact. Not at all desirable and the US tended to use one of the least sensitive explosives from what I recall but it could happen. Also I'm not at all sure the amour penetration programs like facehard take glancing into account. After all shells can glance off the surface of the water.
Re: Shell hits
When detonation on impact happens, it's usually against thick armor, such that the shell is subject to a very large shock on impact.lwd wrote:I believe it's possible for a shell to detonate on contact. Not at all desirable and the US tended to use one of the least sensitive explosives from what I recall but it could happen. Also I'm not at all sure the amour penetration programs like facehard take glancing into account. After all shells can glance off the surface of the water.
When shells ricochet there is a much higher probability of a dud, because of the tremendous G forces affecting the fuse. I'm thinking of a blow which changes the path of the shell substantially, such as bouncing off of a barbette. I doubt richochet off water would do that because the angle would have to be very small or it would dive.
Re: Shell hits
A minor note here, the Mk21 BDF used in US APC shells did not have a graze action element to allow it to initiate after a shallow angle ricochet off water (or anything else for that matter). This is in contrast to the German C/36 or C./38 BdZ fuzes which were graze action types. A US shell was very unlikely to detonate at all in a post ricochet situation, even if subsequently hitting a target, due to yaw-induced irregular stresses which could jam elements of the fuze and prevent final arming.
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.
Re: Shell hits
Hi Byron
Thanks for your detailed reply and in the majority I agree. The SEYDLITZ performance was quite exceptional when compared to what was thrown against her. The Blucher (please forgive the spelling) by staying afloat caused valuable shells to be directed to her rather than her fleeing companions. However, whether destroyed by a hit to the magazine or a chain explosion is rather mute in the British battle-cruiser's case as the result is the loss of an operating ship. Was it the SEYDLITZ or one of her sisters that brought awareness of the chain explosive affect to the attention of the Germans at Dodger Bank? Had not a crew member being so proactive the story might have been different. In my readings a great many hits and the damage they caused are considered lucky but that is the lot of battle.
As for the Tiger performance I suppose again that is the lot of a war time ship as POW, Bismark, amongst others did not have much lead time in working a ship up. The counter for an older ship, say the Hood, is the firing control equipment was not up-to-date so there is always a reason.
A battleship is a serious commitment of a country's resources so if say half become inoperable after a few hits or fail to land hits then is it a failure of design or fact of life? For the first then why was the design so bad and if the second then why direct resources to a battleship?
Programs and books that slam certain designs annoy me as they appear to take a few samples and use them almost as a clique. I like to study why decisions were taken as this process is to me more enlightening as today sitting down are military planners and designers making similar decisions and I wonder if much thought is actually given to the decision making process. I.e. is the best carrier a super carrier or two or three smaller carriers, etc.
In the 1930's designers of battleships I imagined to have analysed shell hits and armour protection schemes to defeat them along with fire control system, yet the results where not inspiring in battle. How did they get it so wrong?
Cheers Brett
Thanks for your detailed reply and in the majority I agree. The SEYDLITZ performance was quite exceptional when compared to what was thrown against her. The Blucher (please forgive the spelling) by staying afloat caused valuable shells to be directed to her rather than her fleeing companions. However, whether destroyed by a hit to the magazine or a chain explosion is rather mute in the British battle-cruiser's case as the result is the loss of an operating ship. Was it the SEYDLITZ or one of her sisters that brought awareness of the chain explosive affect to the attention of the Germans at Dodger Bank? Had not a crew member being so proactive the story might have been different. In my readings a great many hits and the damage they caused are considered lucky but that is the lot of battle.
As for the Tiger performance I suppose again that is the lot of a war time ship as POW, Bismark, amongst others did not have much lead time in working a ship up. The counter for an older ship, say the Hood, is the firing control equipment was not up-to-date so there is always a reason.
A battleship is a serious commitment of a country's resources so if say half become inoperable after a few hits or fail to land hits then is it a failure of design or fact of life? For the first then why was the design so bad and if the second then why direct resources to a battleship?
Programs and books that slam certain designs annoy me as they appear to take a few samples and use them almost as a clique. I like to study why decisions were taken as this process is to me more enlightening as today sitting down are military planners and designers making similar decisions and I wonder if much thought is actually given to the decision making process. I.e. is the best carrier a super carrier or two or three smaller carriers, etc.
In the 1930's designers of battleships I imagined to have analysed shell hits and armour protection schemes to defeat them along with fire control system, yet the results where not inspiring in battle. How did they get it so wrong?
Cheers Brett