Pearl Harbour and other ships

From the Washington Naval Treaty to the end of the Second World War.
paul.mercer
Senior Member
Posts: 557
Joined: Fri Mar 26, 2010 10:25 pm

Pearl Harbour and other ships

Postby paul.mercer » Thu Sep 07, 2017 9:43 am

Gentlemen,
i watched a hypothetical film on Youtube on what WW2 ships would be revealed if the ocean could be drained, in it was sinking of the Arizona. The commentator stated that she was hit in the forward magazine by an armour piercing bomb which effectively blew off the bow. I was wondering if this really was the case as the Japanese planes did not seem to be able to carry a very large bomb and given the low altitude of the attack would a bomb go through all that armour, or was it actually one of their long Lance torpedoes that did the damage?
On another part of the film the old question of whether Bismarck was scuttled was raised, I know this has been discussed at length in other topics, but the images put together suggested that it looked like the plating was actually blown outwards suggesting an internal explosion and they stated that when Bismarck sank she was already full of water so no compression occurred as she reached the depths. However it was also said that she was literally shot full of holes like a colander so I wonder if this might be the reason for her filling up so quickly, also, could the plating busting outward be due to the tremendous impact of around 50,000 tons hitting the sea bed?

OpanaPointer
Member
Posts: 107
Joined: Wed Jul 06, 2011 1:00 pm

Re: Pearl Harbour and other ships

Postby OpanaPointer » Thu Sep 07, 2017 11:08 am

The bomb was a 16" shell shaved down to be more aerodynamic and fins added. The bombers were high-altitude level bombers.

Kev D
Member
Posts: 26
Joined: Mon Jul 25, 2016 5:27 am

Re: Pearl Harbour and other ships

Postby Kev D » Sun Sep 10, 2017 6:21 am

Double post. Removed :negative:
Last edited by Kev D on Sun Sep 10, 2017 6:54 am, edited 2 times in total.
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941

Kev D
Member
Posts: 26
Joined: Mon Jul 25, 2016 5:27 am

Re: Pearl Harbour and other ships

Postby Kev D » Sun Sep 10, 2017 6:48 am

Another double post. Again, removed. :stubborn:
Last edited by Kev D on Sun Sep 10, 2017 6:53 am, edited 1 time in total.
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941

Kev D
Member
Posts: 26
Joined: Mon Jul 25, 2016 5:27 am

Re: Pearl Harbour and other ships

Postby Kev D » Sun Sep 10, 2017 6:49 am

paul.mercer wrote:i watched a hypothetical film on Youtube on what WW2 ships would be revealed if the ocean could be drained, in it was sinking of th I was wondering if this really was the case

Interesting topic, that is You Tube videos / re-enactments of WW!! naval battles.

Most I believe (or should I say most I have seen) should be taken with a grain of salt.

For instance, many videos / footage purporting to show the sinking of HMS Repulse and HMS Prince of Wales is actually footage of HMS Dorsetshire and HMS Cornwall maneuvering and then sinking in the Indian Ocean. As far as I am aware there is no such film footage of Repulse and PoW sinking, although there are several photos taken by Jap aviators well prior to their sinking (i.e. the bombing of Repulse showing smoke from the one hit, and another of both heavies and a DD maneuvering, to name two), and some photos taken by the Capt. of HMS Express - if I am not mistaken - as Pow started rolling to port and sinking (with Express so close alongside she was almost capsized when PoW's stbd bilge keel caught under Express!)

paul.mercer wrote:.........as the Japanese planes did not seem to be able to carry a very large bomb and given the low altitude of the attack would a bomb go through all that armour, or was it actually one of their long Lance torpedoes that did the damage?


On a minor note, I believe Japanese planes did not carry the oxygen 'fueled' Long Lance at Pearl, nor anywhere else for that matter. :negative: :D

paul.mercer wrote:.........but the images put together suggested that it looked like the plating was actually blown outwards suggesting an internal explosion and they stated that when Bismarck sank she was already full of water so no compression occurred as she reached the depths. However it was also said that she was literally shot full of holes like a colander so I wonder if this might be the reason for her filling up so quickly, also, could the plating busting outward be due to the tremendous impact of around 50,000 tons hitting the sea bed?


Although I have not studied 'that battle' well, it is my thinking the sinking was caused / aided by a mixture of scuttling and shell and torp hits, but I think 'what' actually sank her will rage on for ages between both sides as to who should get the 'credit'.

As for the 'blown out plates' being caused from hitting the bottom, not IMO if around a (shell or torp) hole - unless from a through and through shell hit ((or torp explosion as seen on PoW's bow). Can you describe specifically where these 'blown out' plates are / were seen around on Bismarck please?
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941

paul.mercer
Senior Member
Posts: 557
Joined: Fri Mar 26, 2010 10:25 pm

Re: Pearl Harbour and other ships

Postby paul.mercer » Wed Sep 13, 2017 10:14 pm

As for the 'blown out plates' being caused from hitting the bottom, not IMO if around a (shell or torp) hole - unless from a through and through shell hit ((or torp explosion as seen on PoW's bow). Can you describe specifically where these 'blown out' plates are / were seen around on Bismarck please?[/quote]

I'm afraid not, the film had pictures taken of Bismarck on the bottom but did not say where but there was what appeared to be armour plates sticking out from the hull just above the mud line looking as if it had been forced out. What puzzles me is that pictures of the stern of Titanic seems to suggest that water pressure forced through the stern resulted in its almost total destruction, whereas the bow looks relatively intact although crumpled from impact with the sea bed. Bismarck of course was of a much stronger construction and it would seem unlikely that even though she lies around 3000 feet deeper than Titanic that pressure even at that depth would try to crush or blow out her hull. I don't know where scuttling charges would be placed on a ship, although I would guess it would be around the intake valves or sea cocks which I presume would be somewhere near the bottom of the ship - which of course is buried in the mud which would suggest that the visible plating sticking out from her side was caused by the impact with the sea bed. I seem to recall reading somewhere that Titanic's bow was estimated to have reached around 20 knots by the time it hit the bottom, so it would be interesting to estimate whether Bismarck exceeded that bearing in mind she remained intact all the way.
What I would say is that if Bismarck was scuttled, then it took some very, very brave men to go below whilst she was being shot to pieces in order to set the charges off.

OpanaPointer
Member
Posts: 107
Joined: Wed Jul 06, 2011 1:00 pm

Re: Pearl Harbour and other ships

Postby OpanaPointer » Wed Sep 13, 2017 10:47 pm

Didn't the stern of Titanic hit the water hard when the ship broke up?

paul.mercer
Senior Member
Posts: 557
Joined: Fri Mar 26, 2010 10:25 pm

Re: Pearl Harbour and other ships

Postby paul.mercer » Thu Sep 14, 2017 10:39 pm

OpanaPointer wrote:Didn't the stern of Titanic hit the water hard when the ship broke up?


There are some doubts as to whether the stern broke off while she was almost vertical or if it broke away during her plunge to the bottom. Most seem to accept that it snapped off while she was still upright due to the weight bearing down on the stern after the rest of the ship was submerging. But to answer your question, I believe that experts who have studied the wreckage concluded that it was the inrush of water through the stern that caused the stern to almost peel back on itself and of course the tremendous impact of hitting the bottom completed the destruction. The bow of course was intact and it seems that it planed its way down,only crumpling as it plowed into the mud.

Kev D
Member
Posts: 26
Joined: Mon Jul 25, 2016 5:27 am

Re: Pearl Harbour and other ships

Postby Kev D » Sun Sep 17, 2017 7:38 am

paul.mercer wrote:What puzzles me is that pictures of the stern of Titanic seems to suggest that water pressure forced through the stern resulted in its almost total destruction, whereas the bow looks relatively intact although crumpled from impact with the sea bed. Bismarck of course was of a much stronger construction and it would seem unlikely that even though she lies around 3000 feet deeper than Titanic that pressure even at that depth would try to crush or blow out her hull.


Argh, to answer your question re Titanic’s stern verse bow condition Paul. As you recall the big T sunk by the bow, and the cause of sinking was from the flooding, so, the forward 'half' of the ship was already mostly / completely full of water, so 'inside' and 'outside' water pressure was basically equal in the bow as it descended, hence why we see it intact, or basically so.

As for the stern a different matter altogether, but I won’t get into where she broke (in 'half'), i.e. surface or subsurface, save to say it was not like in the movie, and Jim Cameron himself now flatly states that; but it was not flooded (much) so hence went down with most compartments full of air, and the deeper it descended it would have soon / eventually imploded with a mighty bang, which from the few 'implosions' I have seen underwater (of housed cameras, and diver propulsion vehicles or DPV's taken beyond their 'crush depth'), it seems / looks more like an explosion, given what the resultant damage done immediately looks like / begins to do (i.e. fall apart).

So one piece (the bow) went down already full of water at equal pressure as it descended shall we say, the other, the stern, started its descent mostly full of air, and imploded. Hence the difference in ‘look’.

So it is not water rushing ‘through’ the ship that crushes it or breaks it apart (although this does have some effect on internals), it is the external water pressure crushing any air filled pockets and in the process, if it is rapid enough as Titanic seems to have been, then that inrush from the implosion also breaks the ship / object apart. But hence why all these ship now sunk and on the bottom, even in very deep water, will remain un-crushed as they are already full of water (but will slowly fall apart as the metal rots and collapses over the years).

Anyway, I hope I make myself clear in the above re why the crushing / implosion / ‘explosion’ occur, and why the two halves of the big T look so different.

And this 'waterloggedness' is why many ships that where torpedoed, and stayed afloat for a long time, are upright on the bottom, i.e. because they were already 'full' of water before they sank. HIJMS Haguro is a classic shallow water example of this (while on the other hand HMS Prince of Wales is not), and then we have Bismarck, Indianapolis, etc. all upright on the bottom in deep water. But of course the deeper the water a ship sinks in, especially a big ship, then its shape / weight 'distribution' has a tendency to get it 'upright' before hitting the bottom. On the other hand, if that same ship sank / left the surface very fast, basically still full of air, it would be crushed by the external water pressure increasing the deeper it went; or parts crushed (or slowly crushed depending of how fast - or slow as the case may be - the water can get into a compartment) as the effects of such can be seen in some of the pics in Bob Ballard’s book on 'The Lost Ships of Guadalcanal'.

paul.mercer wrote:What I would say is that if Bismarck was scuttled, then it took some very, very brave men to go below whilst she was being shot to pieces in order to set the charges off.


Roger that!!!!! You bet! :clap:
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941


Return to “Naval History (1922-1945)”

Who is online

Users browsing this forum: No registered users and 2 guests