Surfacing Sub Hits Commercial Vessel

I don’t know much about the rules of the road but I guess a vessel approaching from underneath doesn’t have the right of way?

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Kyodo News reported that the crew used a mobile phone to report the accident.

Japan has GREAT cell phone coverage if you can make calls from submarines!

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It is astonishing how frequently this has happened. Straits of Hormuz has seen a few incidents.

Glad to hear no one was seriously hurt.
Is it not routine to use the sonar to scan vertically before surfacing? You would think submariners would be doubly cautious after Greenville collision.

Interested to learn that the sub has lithium ion batteries. I wonder what its submerged range is at, say, 5 knots?

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With the caveat that I was a “skimmer” when serving, I don’t believe vertical sonar is available on subs. . .However, I’d fully expect that the noise from the skimmers propellers would have been VERY LOUD on the sub’s passive sonar - if not audible throughout the hull to the whole crew. SWISH-SWISH, SWISH-SWISH. . .

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Point a fishfinder straight up would show a ship over your head, but not one a few miles away doing 15 knots. I think surface wave reflections would make a mess out of active sonar at a long distance looking up. The ship should be loud on the passive though.

With all the multibillion apparatus on those vessels, surely those type collisions can be avoided somehow. My pop was a “Bubblehead” and missle control dude… Wish he was still here to discuss this subject.

Can happen to anyone I guess.

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There was one off the NE coast a while back that got into the tugs towline with bad results.

He was showing off for the “Elite” passengers that day. (Greeneville skipper)

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That’s what I would have thought. And diesel-electric boats are the quietest of all vessels when submerged on battery power.

I don’t recall hearing a good exploration for the American sub not hearing the ship.

They did hear the Ehime Maru. Here’s the NTSB take on it:
Sixty pages but fascinating.

Tl;dr –

In its review of the events in this accident, the Safety Board determined that qualified and experienced members of the combat management team (the conning officer, the FTOW, and the sonar supervisor) as well as senior officers who happened to be in the control room failed to follow procedures designed to ensure safety in operations. The teamwork problems demonstrated on the day of the collision were due in part to the CO’s overly directive style, particularly with the OOD-2. However, the failure of key watchstanders to effectively perform their duties and communicate vital information to the conning officer contributed to the CO’s committing the following critical errors:
• Failed to perform adequate contact analysis;
• Rushed the procedures for moving to periscope depth; and
• Ordered an emergency surfacing maneuver in the direction of a contact.
Contributing to the operating errors of the combat systems team was their failure to adequately manage the civilian visitors so that they did not distract the watchstanders from the efficient execution of their duties. A detailed discussion of the operating errors follows. The analysis also considers the design of the Ehime Maru and the survivability of the fishing vessel in the accident.


^^It must be remembered that a passive sonar contact gives a bearing but not a range. The combination of submarine motion and target bearing change, strength, assumed speed etc. is used by the sonar techs and equipment to generate speed/position vectors that fit the observed data. This whole process is called Target Motion Analysis, or TMA.

In order to generate definitive or nearly-definitive vectors it’s often necessary for the submarine to radically change course for a time so as to create a second baseline. All this happens at ship speeds rather than the speed of sound. Target course or speed changes invalidate the solution, and improper assumptions by the sonar party (eg Ehime Maru is far away) can generate false solutions (or rather eliminate true solutions from consideration). A fast target far away can give the same observations as a slow one near by.

If you want to discover for yourself how challenging this can be, spend some time with the game 688(I) Hunter/Killer. This game was written by people who do sonar simulation for a living, and it is remarkable. It also has a manual around 3/4 inch thick when printed on copy paper IIRC. I ran it under Windows back in the late '90s, but apparently you can get it on Steam now, presently for ten bucks. I don’t know whether Steam requires a live Internet connection to run.


Having been a recreational and racing sailor in and around the Straits of Juan de Fuca and Admiralty Inlet at the entrance to Puget Sound I can tell you that there are quite a few sailors with bar stories about submarines surfacing unexpectedly and alarmingly close aboard while they’ve been racing or cruising in that area.

The main W. Coast US Navy submarine base of course is at Bangor on Hood Canal which opens off at the S end of Admiralty inlet., Coming in from the sea, right before the Hood canal entrance, there’s what the charts describe as a “Naval Magazine” at the N. end of Indian Island. I’ve never seen a submarine alongside the pier there, but I have seen larger ships. Rumor has it that ships (and submarines?) in/out bound to/from the naval facilities in Puget Sound off/on load their major warheads there but that may just be conjecture.

But there’s certainly a LOT of submarine traffic in that area, so it makes sense that a few have been seen coming and going. I’ve heard a couple of stories of fishermen getting nets fouled on submarines in the area, but no convincing stories about collisions in those parts. I’ve been told that, in normal peacetime operations in high traffic areas, submarines may sometimes send up some kind of flare or visual signal to clear an area before surfacing, but I’ve never personally seen that.


I’ve seen plenty go them surfaced going in and out of Hood Canal with an escort of navy/USCG vessels forming a perimeter for them. No one allowed close. From Hood Canal I guess it would be something like 80 miles to the Pacific. But the water is deep in the Straits, so a sub could easily dive/surface anywhere.

Subs have some way of ranging overhead because they do this under the ice.

That would be some form of active sonar where the boat generates a noise and listens for echoes.

Like a simple high frequency echo sounder with the transducer pointing up instead of down.

That could easily miss a ship that is not directly overhead.

How could they not hear a ships propeller noise? Don’t they have a database of the sound signature of most particular ships. If they hear the ship, they should know it’s name, likely steaming speed and other characteristics.

Interesting that we don’t know the answers, and American submariners are likely not allowed to tell us. More than one reason they are called the Silent Service.

Whatever happened to looking through the periscope before surfacing.

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