3rd March 2010, 22:59
3rd March 2010, 22:59
4th March 2010, 00:17
I suppose it would have been too easy for the sub to stop and have the tug come alongside while it was stopped and transfer mail and passengers.
Some knowledgable USN type said the sub was following S.O.P. I should hope that some redundant admiral somewhere in the depths of the Pentagon would have realised that S.O.P. needs changing. Pretty sad performance all round that cost the life.
4th March 2010, 01:12
When getting away from any moving vessel you NEVER go astern like that.
The sub should have turned gently to port (if able) and the tug should have peeled off to stbd. If not then the sub should have stopped and allowed the tug a clear the side.
4th March 2010, 01:52
The sub seems to have the rudder hard over for a starboard turn to get away from the tug,what sank her,do you think it was the vortex of the sub or was there a rope tangled in the prop of the sub. I remember a video that was shown on SN where a new tug was sucked under somewhere up in Canada.
4th March 2010, 03:52
If you look down the list of videos when viewing this sub/tug video, you will see one labeled Skookumchuk Narrows. It was a case of being in the wrong place at the wrong time with insufficient knowledge of the power of the outflow in the Narrows on an ebb tide.
4th March 2010, 04:29
When the video starts the tug is forward on what could be loosely termed the shoulder. I know subs don't have them however with a stbd turn being executed the tug was essentially steaming to stbd into the tug. If the sub had altered AWAY from tug at that stage the tug would have fallen away from the sub and been able to steam away.
Once the tug tried to go astern she fell back into an area of enormous suction. These subs draw well over 40 foot on the surface and that would be close to four times the draft of a small tug like that. She never had a chance with the stbd swing on like that.
I have personal experience of this in Port Hedland sailing deep drafted bulk carriers drawing 19 + metres. Once they get up to over 4 knots the tugs have a hell of a time getting away from them and they try and clear before then. The added problem of a narrow vertical sided channel as well makes for even more fun!
As these monsters swing to port around Point Cook on departure the wall of water welling up behind them on the port quarter has to be seen to be believed. The suction is suffiecient to drag a tug into the ship and even full astern will not stop it.
Pilots and ships masters need to understand the hydro dynamics that sre going on around their vessels and how little a small vessel to can do once the big one gets up speed. 4 knots seemed to be a magic number..........anything more than that and things can get very hairy very qiuickly.
I wonder if they will ask an experienced tug master to assist in the enquiry of the sinking. I will not be holding my breath.........
4th March 2010, 08:06
Notwithstanding what procedures may or may not have been followed, it is very hard to understand why the sub`s command did not cease travelling forward at such a rate of knots much, much earlier, when it became patently obvious (at least a few minutes before), that this was building up to a major problem.
4th March 2010, 10:11
It seems to be a major problem every time these US subs surface, perhaps they don't get enough time doing surface maneuvers.
4th March 2010, 12:36
It looks like the bottom of the tug may have been sliced open when she was hung up on the plane, which despite the tug going full astern he could not get off until the stern started to sink and the Bow lifted combined with the Sub turning. Possibly similiar damage as with the Japanese Fisheries Training vessel.
4th March 2010, 14:12
Well the Board of inquiry have a very good video of the accident.
4th March 2010, 15:12
There appear to be a number of virtual swords pointing at the sub commander already.
4th March 2010, 15:35
It's certainly not a virtual sinking, the Tugs predicament reminds me of the "Fittleton" tragedy when she got stuck inside the "Mermaids" Bow pressure wave. It would appear that the Sub OC decided that the transfer had been completed and he could increase speed not thinking about the Tug having to clear the inner zone of his Bow wave, I wonder if anyone who works on a Pilot Cutter has any comments as they come across this "type" of situation every day.
Louis XXV de France
6th October 2012, 02:00
After repeatedly and carefully reviewing this old footage, several things seem apparent that are missing from discussions throughout the web regarding this incident.
1. All was well at the conclusion of the transfer of men/materials from or to the tug. At this time the submarine was barely under way; one can tell by the movement of the water early in the video and the lack of relative wind, etc.
2. As soon as the transfer was complete, the submarine begins accelerating; it has been understood since that the tug's prime mover went momentarily off line. This is why the tug boat appears to fall back. It was unable to maneuver for the moment; meanwhile the submarine continues to accelerate away. This becomes obvious to the viewer by the rapid increase of wake and apparent wind. It was then incumbent upon the the officer in command of the submarine to refrain from accelerating or getting under way while the other vessel was not yet clear of his own and well off, even if this turn of events had to be shouted to him by the crew on deck.
3. By the time that the tugboat was able to restore main power, it was already being rammed from behind by the starboard dive plane, which caught and dragged the now doomed tugboat through the water, its hull likely holed already and the prop irretrievably damaged. As clearly revealed in the video by the black soot blowing out his funnel, the master of the tug pushed his diesel with all it had once it was running again, but was unable to free his vessel from the submarine as it continued to accelerate and turn away. When the fatally damaged tug did finally break free of the sub's dive plane, she fell over and sunk almost immediately at the stern.
The primary burden of culpability in this unfortunate incident rests principally with the hasty departure and careless navigation of the submarine. That kind of rushing away from a normally routine ship to ship transfer should only be excused under an emergency or a state of war.
30th December 2013, 00:57
What everyone seems to be missing is the fact that ships are steered from the stern. Because of this, you can't simply turn to port to get away from a craft on your starboard side. Turning to port would swing the stern to starboard and slam it into the tug. If two ships alongside attempt to depart each other simply by turning port and starboard respectively, the result would be for the sterns to slam into each other.
The sub was executing a right full rudder in order to swing the stern away from the tug. The increase in wake was due to the sub increasing speed in order to swing away from the tug faster. This was necessary due to the tug failing to pull clear quickly enough. It is a standard procedure which is absolutely correct.
The correct procedure for a tug to depart from alongside a sub is to turn perpendicular to the hull of the sub and back away quickly. Since the tug failed to do this (possibly due to loss of propulsion) she drifted astern and landed on the stern planes. At that point, there was little the sub could do other than to continue the turn in hope that the plane would clear the tug or be pulled out from under the tug.
The obvious cause of this incident was the coxwain of the tug failing to avoid the stern planes of the sub. He initially backed away parallel to the sub, which was the fatal mistake.
The tug sank itself by attempting to reverse at full power with the stern down. Essentially, the coxwain simply drove his craft under in reverse. The hull of the tug was not breached. The smoke was caused by accelerating the engines.
A submarine a that speed has no bow wake large enough to overcome a tugboat, which has an extremely high power to weight ratio. (It is strong enough to push the sub around like a bathtub toy)
The captain of the sub did not cause this collision. The inexperience of the tugboat coxwain did. Had he been aware of the presence of the stern planes, and had followed the correct procedure, this would not have happened. Had he not panicked and attempted to back his craft too fast with his stern buried, he wouldn't have sunk himself.
Ringing an astern bell on the main engines of the sub would not have changed the ship's way from ahead to astern quickly enough to have avoided this.
30th December 2013, 10:50
I I wonder if anyone who works on a Pilot Cutter has any comments as they come across this "type" of situation every day.
Large light ships making a lee for the pilot cutter would often blow down on the cutter making it very difficult to get off the side. The answer was as soon as you arrived on the bridge turn the ship into the wind.
31st December 2013, 00:12
good day samuell j 2010,08:59,re:us navy sub accidentlly sinks tug boat at midway island.i was reading this old thread.watched your interesting link.i cannot commemt on who's at fault,but it was good to see all hands were saved,a happy new year to you and your family,regards ben27
31st December 2013, 22:15
Discussed a while ago here:
If no link, Google ---
The Stupid Shall Be Punished
archives for May, 2010, and scroll down near the bottom
OliverD CMC (ret) (USNR)