The Ship Model Forum

Tshipley wrote:Ron, by chance have you read "Boys of the Battleship North Carolina" by Cindy Ramsey? It is a great read about the crew stories tying them to the ship's log.

Nope, I've read her decklog and damage reports and have full copies of the latter.

Ron, by chance have you read "Boys of the Battleship North Carolina" by Cindy Ramsey? It is a great read about the crew stories tying them to the ship's log.

Werner wrote: I wonder if the "smoke" was not indeed dust and paint flakes dislodged by the compression waves that would have proceeded across the width of the ship and for some odd distances fore and aft....

Could be, it was reported a grey or yellowish grey. Some could also be pulverized ceramic as a head and shower were pretty much crushed. One man was showering and died there.

The handling room flooding was a rate of 50 gallons per hour leakage caused by a deflected rollerpath support and loosened rivets. Flooding second deck and above was due to ruptured or loosened seams where the compartments immediately below were flooded. A number of compartments were deliberately counter flooded to remove the list, she was list free and resumed steaming within six minutes of the hit. Total weight gained from all flooding 970 tons, at no time was flooding severe enough to endanger the ship. At Tongatabu Vestal cut away some blown out plating along the hull, assisted in shoring the damaged structures, sealing leaks and retrimming the ship 7 feet down at the stern. During the trip to Pearl the few leaks that existed were dealt with using temporary pumps run for 15 minutes each watch.

All smoke was believed to be from the initial explosion, no fires resulted. Probably the initial flash of the explosion scorched a few things that contributed to the smoke. Compartments A-310-L and A-317-T are the only compartments to report a confirmed flash. Reported but unconfirmed flash powder handling room and access trunk. A magazine fire was reported but no evidence of fire was ever found in the magazine. As a precaution only the sprinklers were activated in the powder handling rooms and magazines of turret 1, they were turned off quickly as no fires were evident.

Turret 1 had a distorted roller path with burrs that prevented training, the burrs were removed and the turret could be trained. Its use was restricted to "situations of extreme gravity" until it could be adequately tested. Part of the structural concerns were bulkheads crushed against the turret stool and the possibility it was forced off axis or had hidden damage.

Most severe in terms of combat capability was the increased vibration to the forward fire control instruments and the shock damage to the main radar antenna.

No cause was ever determined for the 4 dead men with singed hair.

Dick J wrote:

Tshipley wrote:Turret One was out of commision until she returned to Pearl Harbor as Ulithi did not have the proper facilities to repair her.

Just a minor point, but Ulithi was not yet in US hands. Forward base repairs were being done at Esprito Santo, and no drydock facilities were available there.

Done specifically at Tongatabu assisted by Vestal.

Werner wrote: That's what I thought, too. I didn't say anything because I didn't have the reference handy (and I already goofed on the weight of mild steel). The innermost bulkhead is meant to be deformed many feet without rupture in North Carolina. In the later classes, they extended the armor down to the inner bottom with negative consequences for torpedo protection. North Carolina was probably the safest modern US battleship in the area of torpedo defense.

The relative advantage of extending side armor down to the bottom is a debated issue. Experience of Bismark and POW clearly shows the potential for long range steeply diving shells to penetrate below normal belt is no joke. It is in principle plausible, and by no means yet disprove as an actuality, that the penetrating hit which destroyed the Hood was an underwater hit that pierced the TDS.

Anonymous wrote:

Werner wrote: 30 pound steel is 1 1/4 inches, is it not? As I recall, the innermost bulkhead was mild steel, the others ductile steel.

For comparison, a Gato's pressure hull was 11/16 inch of mild steel.

The singed hair sounds like it may have been a consequence of electrostatic effects of the explosion. That sounds even more dangerous than flash.

That's backwards. The innermost bulkhead in the TDS is the one intended to absorb any remaining explosive force by elastic membrane deformation, and then return to its original shape after the explosive force is spent. To allow this bulkhead to deform as necessary, it is usually unsupported in the middle by any frame and rely on its own strength for structural integrity. So this bulkhead is usually fairly thick, strong, and built of elastic high tensile steel.

The intermediate bulkheads inside the TDS were sacrificial, and intended to progressive absorb the force of the explosion by rupturing one after another. So those bulkheads are usually ductile mild steel. Furthermore, in the process of rupturing, these bulkheads must not generate fragments and splinters so massive such that when propelled by the remaining explosion they could be driven through the inner most bulkheads. So these intermediate bulkheads are usually fairly lightly built.

That's what I thought, too. I didn't say anything because I didn't have the reference handy (and I already goofed on the weight of mild steel). The innermost bulkhead is meant to be deformed many feet without rupture in North Carolina. In the later classes, they extended the armor down to the inner bottom with negative consequences for torpedo protection. North Carolina was probably the safest modern US battleship in the area of torpedo defense.

Werner wrote:

Tiornu wrote:That's a good point. The 3rd deck, just 30-lb outboard of the inner belt, was completely mangled. The potential path of flash from that space to other inboard spaces is not readily aparent from the material I have, but it is cerrtainly conceivable.
While none of the powder was scorched at all, the four crewmen who died at the point of the blast had their hair singed off.

30 pound steel is 1 1/4 inches, is it not? As I recall, the innermost bulkhead was mild steel, the others ductile steel.

For comparison, a Gato's pressure hull was 11/16 inch of mild steel.

The singed hair sounds like it may have been a consequence of electrostatic effects of the explosion. That sounds even more dangerous than flash.

That's backwards. The innermost bulkhead in the TDS is the one intended to absorb any remaining explosive force by elastic membrane deformation, and then return to its original shape after the explosive force is spent. To allow this bulkhead to deform as necessary, it is usually unsupported in the middle by any frame and rely on its own strength for structural integrity. So this bulkhead is usually fairly thick, strong, and built of elastic high tensile steel.

The intermediate bulkheads inside the TDS were sacrificial, and intended to progressive absorb the force of the explosion by rupturing one after another. So those bulkheads are usually ductile mild steel. Furthermore, in the process of rupturing, these bulkheads must not generate fragments and splinters so massive such that when propelled by the remaining explosion they could be driven through the inner most bulkheads. So these intermediate bulkheads are usually fairly lightly built.

Tiornu wrote:A 30-lb plate is .75in. In this portion of the hull, the innermost torpedo bulkhead was the thickened inner belt of 2-3.75in STS. Bulkheads 1-4 are not labeled, so I take it to mean they are mild steel.

You're right. I was thinking of the weight of 1/2 inch steel. My bad.

A 30-lb plate is .75in. In this portion of the hull, the innermost torpedo bulkhead was the thickened inner belt of 2-3.75in STS. Bulkheads 1-4 are not labeled, so I take it to mean they are mild steel.

Tiornu wrote:That's a good point. The 3rd deck, just 30-lb outboard of the inner belt, was completely mangled. The potential path of flash from that space to other inboard spaces is not readily aparent from the material I have, but it is cerrtainly conceivable.
While none of the powder was scorched at all, the four crewmen who died at the point of the blast had their hair singed off.

30 pound steel is 1 1/4 inches, is it not? As I recall, the innermost bulkhead was mild steel, the others ductile steel.

For comparison, a Gato's pressure hull was 11/16 inch of mild steel.

The singed hair sounds like it may have been a consequence of electrostatic effects of the explosion. That sounds even more dangerous than flash.

That's a good point. The 3rd deck, just 30-lb outboard of the inner belt, was completely mangled. The potential path of flash from that space to other inboard spaces is not readily aparent from the material I have, but it is cerrtainly conceivable.
While none of the powder was scorched at all, the four crewmen who died at the point of the blast had their hair singed off.

NC's torpedo bulkhead is situated inboard of the lower edge of the armor belt. Consequently there is a relatively unprotected passage leading over the top of the TDS into the upper decks inside the citadel. It is seem possible that after rupturing the outer shell, some of the explosive gases vented themselves upwards along one of the unruptured bulkheads of the TDS into the space above the torpedo bulkhead, but behind the belt armor and below the armor deck. From there they can then propagate into the ship's citadel. This may account for the smell in the ship after the torpedo explosion.

Since the decks behind the armored deck is at or above waterline, it would be possible for gas emanate from there into the ship without subsequent flooding of the same passage. However, the powder magazine is underwater, and any passage allowing the penetration of flame or smoke, unless by an extremely circuitous route, would manifest itself in subsequent flooding.

- Chuck

Tiornu wrote:There was flooding in the magazines. One would think that smoke from the explosion (there was no other smoke and no fires at all) would indicate compartments that would also be subject to flooding, but that turned out not to be the case; smoke was detected in all compartments near the point of impact
The crew made some minor repairs to turret 1, after which the turret "trained without difficulty." Use of the turret was restricted out of structural concerns.

I wonder if the "smoke" was not indeed dust and paint flakes dislodged by the compression waves that would have proceeded across the width of the ship and for some odd distances fore and aft....

There was flooding in the magazines. One would think that smoke from the explosion (there was no other smoke and no fires at all) would indicate compartments that would also be subject to flooding, but that turned out not to be the case; smoke was detected in all compartments near the point of impact
The crew made some minor repairs to turret 1, after which the turret "trained without difficulty." Use of the turret was restricted out of structural concerns.

The effects Chuck refers to are called "phosphenes" and is a well-understood phenomena. It is reasonable to assume this is the case in any number of reported explosions, especially those reporting "blue" or "greenish blue" light.

You can safely duplicate the effect by gently pressing in on the white of your eye while in the dark.

Tiornu wrote: There were reports of flame in a powder room but no signs of it could be found. Flash was reported, not in a powder room, but a handling room. There is a possibility that the crewmen were not seeing flash but instead experiencing an illusion caused by the compression of the eyeballs by the force of the detonation. However, the smell of smoke was strong, and it must have come from somewhere.

Was there flooding in the powder room? If the flash of the explosion indeed penetrated the powder room, then surely it must have done so through an aperture punctured from the site of the explosion through the torpedo bulkhead. Since the USN did not use water exclusion barriers in the French manner, any such aperture would cause flooding in the powder room once the explosion gases have vented. So if there were no flooding in the powder room after the hit, then there were no real flame or flash from the explosion. Perhaps a electric spark from shock response.

BTW, I believe that after the torpedo hit, the guns of A turret can still be fired, but the turret itself can not longer train. So its availability in an emergency was completely theoretical and unlikely to have any practical effect.

The notion that the magazine explosion may have come immediately before, and was the proximal cause of, Scharnhorst's sinking was advanced in the documentary covering the Norwegian underwater survey of the hull. The reasons, if I recall, advanced for this suggestion were the following:

1. The ship was clearing going to sink as result of battle damage but the actual foundering was surprising abrupt. Evidence of impending loss of stability was not clearly observed minutes prior to the capsizing.

2. The ship was observed minutes prior to capsizing and minutes after capsizing, but was obscured at the time of capsizing. However large flashes, rather more sustained than can be accounted for by a torpedo detonation, was seen at approximately the time of the capsizing.

Based on this the documentary suggested that a torpedo impact penetrated the TDS near forward magazine and detonated it while the ship was still on the surface.

My own suggestion is that, if this had happened, it could have come about as result of one several factors:

1. The TDS on Scharnhorst noticeable narrows towards the fore and aft turrets. Thus is effectiveness there are reduced from the what is assessed at the mid-ship section.

2. The hit near A turret may represent the second torpedo strike on the same section of TDS around the turret. A TDS section that has absorbed a torpedo losses almost its entire protective value to any second hit.

3. The ship might have listed sufficiently, or the rough sea might have effect torpedo depth control, such that the hit struck against the bottom rather than TDS.

I am not saying Scharnhorst was blowup on the surface by magazine detonation. But I see not reason why such a scenario would be intrinsically difficult to accommodate within the ship's design and her state just prior to sinking.

JWintjes wrote:

Anonymous wrote:The wreckage suggests that the Scharnhorst suffered a forward turret magazine explosion which may have been caused by a similar torpedo hit as described above.

Could you go into more detail about that? As far as I know the evidence of the survivor's doesn't suggest a magazine explosion.

Jorit

The Norwegian survey of Scharhorst's wreckage shows the hull around A and B barbettes has apparently been completely demolished in a manner strongly suggestive of magazine detonation. The hull was intact from behind B barbette to just behind the rudder post. But the tip of the stern has also been violently destroyed or torn away in a manner much more brutal than the loss of Bismark's stern.

JWintjes wrote:

Tiornu wrote: Scharnhorst survivors confirm that her big explosion came after she sank. Considering the German magazine arrangement, I suspect she was less susceptible to torpedo-induced magazine explosion and more susceptible to gunfire-induced magazine explosions. During the battle, 14in shells caused fires in two 28cm magazines and one 15cm magazine.

Ah, ok - an explosion after she sank is indeed what I remember from sifting through the survivors' accounts (which admittedly is quite some time ago).

Jorit

Considering the physical properties would make an explosion underwater seem more powerful, we have to remember that a sunk ship will experience several loud "explosions" as the remaining watertight bulkheads collapse and let out any large remaining air pockets. I would expect this to be more true of a large warship than a commercial vessel.