Comments on: The Attack Analysis http://ussgrunion.com/blog Details and Log reports of the search for the lost WWII Submarine, USS Grunion Thu, 17 May 2012 21:41:30 +0000 http://wordpress.org/?v=2.7.1 hourly 1 By: Travis Mullan http://ussgrunion.com/blog/attack-analysis/comment-page-3/#comment-246225 Travis Mullan Fri, 08 Oct 2010 19:03:02 +0000 http://ussgrunion.com/blog/attack-analysis/#comment-246225 I have been reviewing the photographs, CDs and discussion for the umteenth time in an attempt to come up with a reasonable explanation for the missing bow section and the battery room, control room failure to implode. Beginning with the midship area I would like to propose the following: In re-examining the conning tower hatch and surrounding area I have found it reasonable that the damage to the area may not have been due to physical contact, with the sea bottom for instance, but due to the beginnings of implosion. The conning tower pressure hull is supported at its forward end by the vertical bulkhead which does not appear to have much distortion. The next supporting structure, with the exception of the strengthening rings, is in the area of the periscope shears. Located between the periscopes and the forward bulkhead is the access hatch to the bridge which is located forward on the starboard side. Looking at this area on the Grunion photos there is a great deal of downward distortion of the upper conning tower pressure hull mainly in the center. This distortion has caused the periscopes to be drawn forward and down. In looking at the hatch it can be seen that the hatch trunk has been drawn downward on the port side as the conning tower distorted downward. This progressed until the hatch separated from the hatch trunk alowing water ingress to the hull. Once the separation occurred the inflow of water stopped further distortion of the conning tower. As the sea water entered through the distorted hatch it ran into the conningtower and then down into the control room and pooled against the forward bulkhead and in the pump room below. The inflow of water began to compress the air within the sealed control room and after battery heating it as the pressure increased. If the battery had been spilling acid due to the extreme down bubble the acid would mix with the sea water and generate gas. As the air temperature continued to increase a flash fire would have swept these compartments and possibly touched off a battery explosion. If the explosion were of sufficient force it could account for the open hatch behind the conning tower fairwater. I hope that this will generate some thought about this area and possibly some other ideas as to what happened here. Regarding the 25 feet of missing bow area: Several Gato and Balao boats experienced uncontrolled dives before, during and after WWII. Those that survived these traumatic occurrences have documented the cases well. The reasons range from jammed hydroplanes to errors in ballast and boyancy tank control. For whatever reason, if the Grunion found herself in a similar situation she would probably have been traveling forward with an increasing bow down attitude. Blowing ballast first and then reversing the motors have been documented as successful in some of the survivor cases. In the case of the Grunion let’s say that they were unable to recover in time. With the bow being the lowest point on the boat it would be subjected to the greatest amount of sea pressure and would be the first compartment to implode. The loss of boyancy and increased weight at the bow would increase the forces already working to sink the boat. In reviewing the photos and video of the wreck it is clear that the colapsed compartments did so from the overhead in a downward direction. This may be due to the structural strength provided by the internal decks. The bulkheads seem to have withstood the forces well and maintained their shape. The forward area of the forward battery room overhead looks quite similar to the torpedo room overhead area on the other side of the bulkhead. Let’s say that the torpedo room colapsed from the overhead downward which would deform the metal downwards and inwards resulting in the beginnings of the deformation observed on the wreck as she was found. As the boat continued toward the sea floor the forward battery would have been the next compartment to colapse. This would result in additional loss of boyancy and encreased weight on the forward end of the sub. Finally with no boyancy remaining the Grunion would have impacted the sea bed with considerable velocity. We know that she struck bottom on the slope of a sea mount which would have resulted in an impact at an angle of somewhat less than 90 degrees. Picture the forward torpedo room with the overhead colapsed to the deck level, as in evidence in the case of the other compartments, and with a raised area to the torpedo room/battery room bulkhead. The forward area of the bow may very well have imbedded itself in the sea bottom and sheared off in front of the forward ballast tank, the pit area. If the bow was bent downward and was overrun by the sub what remained of the bow may bave impacted the bottom a second time before the stern settled and she slid the remainder of the way to the bottom. This would account for the way the hull is deformed at the bow as she sits on the bottom now. Please share your thoughts and ideas. I have been reviewing the photographs, CDs and discussion for the umteenth time in an attempt to come up with a reasonable explanation for the missing bow section and the battery room, control room failure to implode. Beginning with the midship area I would like to propose the following:
In re-examining the conning tower hatch and surrounding area I have found it reasonable that the damage to the area may not have been due to physical contact, with the sea bottom for instance, but due to the beginnings of implosion. The conning tower pressure hull is supported at its forward end by the vertical bulkhead which does not appear to have much distortion. The next supporting structure, with the exception of the strengthening rings, is in the area of the periscope shears. Located between the periscopes and the forward bulkhead is the access hatch to the bridge which is located forward on the starboard side. Looking at this area on the Grunion photos there is a great deal of downward distortion of the upper conning tower pressure hull mainly in the center. This distortion has caused the periscopes to be drawn forward and down. In looking at the hatch it can be seen that the hatch trunk has been drawn downward on the port side as the conning tower distorted downward. This progressed until the hatch separated from the hatch trunk alowing water ingress to the hull. Once the separation occurred the inflow of water stopped further distortion of the conning tower.
As the sea water entered through the distorted hatch it ran into the conningtower and then down into the control room and pooled against the forward bulkhead and in the pump room below. The inflow of water began to compress the air within the sealed control room and after battery heating it as the pressure increased. If the battery had been spilling acid due to the extreme down bubble the acid would mix with the sea water and generate gas. As the air temperature continued to increase a flash fire would have swept these compartments and possibly touched off a battery explosion. If the explosion were of sufficient force it could account for the open hatch behind the conning tower fairwater.
I hope that this will generate some thought about this area and possibly some other ideas as to what happened here.

Regarding the 25 feet of missing bow area:

Several Gato and Balao boats experienced uncontrolled dives before, during and after WWII. Those that survived these traumatic occurrences have documented the cases well. The reasons range from jammed hydroplanes to errors in ballast and boyancy tank control. For whatever reason, if the Grunion found herself in a similar situation she would probably have been traveling forward with an increasing bow down attitude. Blowing ballast first and then reversing the motors have been documented as successful in some of the survivor cases. In the case of the Grunion let’s say that they were unable to recover in time. With the bow being the lowest point on the boat it would be subjected to the greatest amount of sea pressure and would be the first compartment to implode. The loss of boyancy and increased weight at the bow would increase the forces already working to sink the boat.
In reviewing the photos and video of the wreck it is clear that the colapsed compartments did so from the overhead in a downward direction. This may be due to the structural strength provided by the internal decks. The bulkheads seem to have withstood the forces well and maintained their shape. The forward area of the forward battery room overhead looks quite similar to the torpedo room overhead area on the other side of the bulkhead. Let’s say that the torpedo room colapsed from the overhead downward which would deform the metal downwards and inwards resulting in the beginnings of the deformation observed on the wreck as she was found. As the boat continued toward the sea floor the forward battery would have been the next compartment to colapse. This would result in additional loss of boyancy and encreased weight on the forward end of the sub. Finally with no boyancy remaining the Grunion would have impacted the sea bed with considerable velocity. We know that she struck bottom on the slope of a sea mount which would have resulted in an impact at an angle of somewhat less than 90 degrees. Picture the forward torpedo room with the overhead colapsed to the deck level, as in evidence in the case of the other compartments, and with a raised area to the torpedo room/battery room bulkhead. The forward area of the bow may very well have imbedded itself in the sea bottom and sheared off in front of the forward ballast tank, the pit area. If the bow was bent downward and was overrun by the sub what remained of the bow may bave impacted the bottom a second time before the stern settled and she slid the remainder of the way to the bottom. This would account for the way the hull is deformed at the bow as she sits on the bottom now.

Please share your thoughts and ideas.

]]> By: Matt Turner http://ussgrunion.com/blog/attack-analysis/comment-page-3/#comment-215779 Matt Turner Tue, 30 Mar 2010 02:04:46 +0000 http://ussgrunion.com/blog/attack-analysis/#comment-215779 i do have a question? what was the final moments of the Uss grunion i mean it sounds like she was deph charged more then a couple times for this much damage to the sub and also did anyone on the dives find the torpedo hatches open? i do have a question? what was the final moments of the Uss grunion i mean it sounds like she was deph charged more then a couple times for this much damage to the sub and also did anyone on the dives find the torpedo hatches open?

]]> By: G Wilson http://ussgrunion.com/blog/attack-analysis/comment-page-3/#comment-169176 G Wilson Mon, 20 Apr 2009 05:47:18 +0000 http://ussgrunion.com/blog/attack-analysis/#comment-169176 I have studied the images on this site and read through most of the comments on the condition of Grunion as she lies on the bottom. The images, drawings, plans and research are extraordinarily well done. In my opinion the catastrophic damage to the bottom half of Grunion's hull is most probably due to heavy impact with the bottom after falling 500 fathoms while full of water. Topside damage could have been the result of rolling over and sliding down the slope- although my first thought was that she had been run over by a surface ship. Images most certainly show a large impact explosion- of whatever cause- which started Grunion on her last dive. The huge amount of damage topside was caused by that set of impacts as shown in the images and exhaustively discussed. Regarding the conning tower hatch- bent into a "U" shape and the missing bow, I offer another possible explanation: Explosive combustion (dieseling) inside the hull caused by extremely rapid compression of air in the hull mixed with oil (hydraulic, fuel oil, lube oil...) as water enters the compartment quickly. When a sub goes down it retains air in each compartment if it is intact . As the water rushes in at at phenomenal rate, the hydrocarbons and air in the compartment compress and explode. The resultant explosions blow out each bulkhead one by one as the sub sinks. In the bow torpedo room the explosion might either blow the bow off by itself or trigger secondary explosions (torpedo warheads principally) which blow the bowcap (the rounded end of the pressure hull) off the submarine. This phenomenon could also be the cause of the conning tower hatch damage and probably the battery hatch (it appears the dogs on the hatch have been torn off leaving the hatch looking normal in its locked up position.) The bow of the I-52 has a similar missing portion-bowcap and outer hull- probably due to a dieseling explosion in the forward torpedo compartment. I have studied the images on this site and read through most of the comments on the condition of Grunion as she lies on the bottom. The images, drawings, plans and research are extraordinarily well done. In my opinion the catastrophic damage to the bottom half of Grunion’s hull is most probably due to heavy impact with the bottom after falling 500 fathoms while full of water. Topside damage could have been the result of rolling over and sliding down the slope- although my first thought was that she had been run over by a surface ship.

Images most certainly show a large impact explosion- of whatever cause- which started Grunion on her last dive. The huge amount of damage topside was caused by that set of impacts as shown in the images and exhaustively discussed.

Regarding the conning tower hatch- bent into a “U” shape and the missing bow, I offer another possible explanation: Explosive combustion (dieseling) inside the hull caused by extremely rapid compression of air in the hull mixed with oil (hydraulic, fuel oil, lube oil…) as water enters the compartment quickly.

When a sub goes down it retains air in each compartment if it is intact . As the water rushes in at at phenomenal rate, the hydrocarbons and air in the compartment compress and explode. The resultant explosions blow out each bulkhead one by one as the sub sinks. In the bow torpedo room the explosion might either blow the bow off by itself or trigger secondary explosions (torpedo warheads principally) which blow the bowcap (the rounded end of the pressure hull) off the submarine. This phenomenon could also be the cause of the conning tower hatch damage and probably the battery hatch (it appears the dogs on the hatch have been torn off leaving the hatch looking normal in its locked up position.)

The bow of the I-52 has a similar missing portion-bowcap and outer hull- probably due to a dieseling explosion in the forward torpedo compartment.

]]> By: Travis Mullan http://ussgrunion.com/blog/attack-analysis/comment-page-3/#comment-145123 Travis Mullan Mon, 05 Jan 2009 20:16:23 +0000 http://ussgrunion.com/blog/attack-analysis/#comment-145123 See link below for picture of a torpedo test on a deactivated fleet sub: http://www.navsource.org/archives/08/0829206.jpg See link below for picture of a torpedo test on a deactivated fleet sub:

http://www.navsource.org/archives/08/0829206.jpg

]]> By: Dylan http://ussgrunion.com/blog/attack-analysis/comment-page-3/#comment-144756 Dylan Sun, 04 Jan 2009 06:41:30 +0000 http://ussgrunion.com/blog/attack-analysis/#comment-144756 the circle runner is a very big Possibility...It happened to the USS Tang and is suspected in the sinking of other fleet boats....If the USS could be photographed, we could compare the damage from her torpedo strike with the possible possible torpedo damage on the grunion. the circle runner is a very big Possibility…It happened to the USS Tang and is suspected in the sinking of other fleet boats….If the USS could be photographed, we could compare the damage from her torpedo strike with the possible possible torpedo damage on the grunion.

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