Encounters of the Submarine Kind

[Grateful]

Originally Posted by kish

In 1997 I sailed on a yacht through a submarine exercise area off of North West Scotland and was hailed by a British warship, 12 miles to the east, and requested to alter course.
It was early evening with no engine running, sailing in a force 6 wind.
Some 10 minutes later we were subject to a mighty low pitched rhythmic acoustic noise loud enough to disturb the crew below deck. This lasted about 2 minutes.
It was not the doorbell style "ping" shown in submarine movies, but a mighty high decibel level, cabinet rattling base sound.
There was nothing visible on the surface and no further communication with the warship.

Those were the facts and here is my interpretation:
Presumably we were being "pinged" by a submarine.
Scary. as trawlers in the western Scottish and Irish Sea areas have been sunk by being towed backwards and foundering.
It is well known that submarines use the noise of shipping to hide from pursuers by steaming underneath the surface ship and it's acoustic shadow.
A 12 metre yacht with no machinery operating, and correspondingly quiet, would present an ideal exercise opportunity to a submarine and a sonar blast will locate it.
A steel hulled ship would not feel the sub's sonar used to position itself underneath as a yacht would.

Kish - I think your analysis is spot on. In the mid-'80's my wife, daughter, and I were sailing between Nisqually Reach and the Tacoma Narrows - inland waters in the US Pacific Northwest - not too far from the USN Pacific Fleet sub base in Bremerton, Washington.

It was a calm afternoon and we were ghosting along in a 21' composite sailboat. Suddenly, there was a very deep rumble so powerful that a glass sitting on a counter began to move on its own from the vibration.

The sound stopped and moments later a DE boat surfaced about 250 meters off our port beam. (I will tell you that when a sub surfaces unexpectedly next to your tiny boat, 250 meters seems like 10 meters.)

I am sure that what we felt was active location. I wonder if they saw ("heard") us. There was some concrete and steel punchings encased in the keel of the boat, so perhaps that gave a return. I know that a miss is as good as a mile, but wow, that felt close.

[ZULU40]

Originally Posted by hsi88

These folks have made over 100 subs for secondary navies. Why do I not feel safer knowing there are hundreds of subs operating outside of the major powers. I'm shocked there have not been more incidents (of any kind). Learn something new every day!

the type would have seen considerable development in that time though, they are known to be a durable platform with much to recommend them. For Australia in particular the operating envelope was much to small, being more suitable for the Eurpean/Mediterainian theater, the Pacific environment required something larger. If you think back to WWII the USN did the same thing with the successful Gato class boats.

Australia went for the Kockums design principaly as it has a notably high degree of automation to reduce crewing.

[williamtl]

I sent a link to this thread to a retired Navy Sub officer. He provided the following which might account for some of the sound that was in the OP.

The only way I think this could have been a sub is if the sub was preparing to surface and then saw the ship close by and aborted. This could explain the lights - if a sub is preparing to surface they turn on their lights before they even are on the surface. This could explain the sound - when a sub surfaces they use (really big) blowers to push air into the ballast tanks. These air pretty loud and wouldn't sound like a diesel. This could also explain the reason why the sound and lights disappeared after a very short period of time. While a sub (at least US sub's) never wants to be close to any surface contact (the captain is on the bridge if a contact gets within 4K yards and we like to keep CPA-
closest point of approach for all contacts >8K yards). So while the sub does go to periscope depth, do a good sweep for surface contacts before starting to surface and then begin the surfacing process it is possible the ship wasn't seen until after the surfacing process actually was started.

[reed1v]

Originally Posted by williamtl

I sent a link to this thread to a retired Navy Sub officer. He provided the following which might account for some of the sound that was in the OP.

The only way I think this could have been a sub is if the sub was preparing to surface and then saw the ship close by and aborted. This could explain the lights - if a sub is preparing to surface they turn on their lights before they even are on the surface. This could explain the sound - when a sub surfaces they use (really big) blowers to push air into the ballast tanks. These air pretty loud and wouldn't sound like a diesel. This could also explain the reason why the sound and lights disappeared after a very short period of time. While a sub (at least US sub's) never wants to be close to any surface contact (the captain is on the bridge if a contact gets within 4K yards and we like to keep CPA-
closest point of approach for all contacts >8K yards). So while the sub does go to periscope depth, do a good sweep for surface contacts before starting to surface and then begin the surfacing process it is possible the ship wasn't seen until after the surfacing process actually was started.

Too bad the navy does not do this all the time rather than just surfacing no matter what; and sometimes at full speed. They are also suppose to acoustically search the surface before going to periscope depth since a lot of ships need 30-40 feet draft and that is below where the sub can scan the surface. Anyways, modern subs are suppose to be quiet in operations with the exception of blasting their way to the surface. Engines still will be quiet.

[neophytecruiser]

Approaching the sea buoy to San Diego Bay early one June morning, I noticed an icon on the Vesper AIS which I didn't recognize. There were several of the Navy security aluminum RIB patrol boats maneuvering, each showing as typical small boat AIS icons with a military ID. The odd AIS icon appeared as a diamond shape with a cross in the center. Listening to VHF traffic, a submarine had just surfaced off shore and was preparing to enter the bay to Ballast Point. Apparently, this odd AIS icon was that of the submarine.

[sailpower]

Originally Posted by reed1v

Too bad the navy does not do this all the time rather than just surfacing no matter what; and sometimes at full speed.

Submarines don't surface at full speed no matter what.

Obviously there have been a few mistakes made but that is not the norm.

[Viking Sailor]

At least one missile was fired by a Russian submarine in the eastern Mediterranean at Syria this morning.

News from The Associated Press

There could be more Russian subs in the MED. You might want to stay in shallow water when possible.

[sailpower]

Originally Posted by Viking Sailor

At least one missile was fired by a Russian submarine in the eastern Mediterranean at Syria this morning.

News from The Associated Press

There could be more Russian subs in the MED. You might want to stay in shallow water when possible.

There are LOTS of submarines operating in the Med.

You can bet that one of our boats wasn't very far from the Russian boat.

[sailorboy1]

As an ex US Navy sub sailor so of you guys just crack me up

[Raythesailor]

A most interesting thread but I must say not that long ago all you submariner experts could have been subject to what we call in the UK "TheOfficial Secrets Act" !!

[Hobiehobie]

Passed this leaving Ft Lauderdale, FL.

[W3GAC]

Us Navy only had one diesel sub left on their fleet 10 yrs ago. It was just used to test new sub gadgets and had an 'after market' extended/ hollow nose whose inside could only be accessed via diver and high pressure sea door. It was the Dauphin and based in San Diego and only ventured out to the deep trench off SD and back. Takes 4 hrs to get way down deep & and about same coming back up if following safety procedures. I was on it while it was dry docked on San Diego and company I worked for at the time had had some of it listening devices/ technology tested by the Dauphin. I never heard it running on the water. But based on what I know about nukes... you wouldn't hear any mechanical noise as it passed by... nothing... maybe just some bow wake splash if moving at fast cruising speed surfaced. In 20+ years of cruising wife & I have had two sub encounters. Once one way to St Thomas and in abt 7,000 ft deep water (the trench) we suddenly saw 'football stadium' lights suddenly cone on abt 1 nm from us. We could see a big cargo type ship with several very very big/ strong cranes that was holding a very big sub in position and conveyor belts were lowering supplies onto/ down into the sub while and crew were coming up out of the sub with their duffel bags and (new?) crew were going into the sub at a different deck entrance. about 15 minutes later the cranes disengaged and all the light went out. I was told later we witnessed a resupply & crew change. On a Galveston to Tampa non-stop straight line across the Gulf of Mexico, we suddenly received a call on ch 16... 'Sailboat approx position... this is US Navy'. They wanted me to deviate from my course 90 degrees... NOW!' Of course we did, but since we couldn't see any ship or airplane anywhere, my Curiosity got the best of me and I had to ask 'where are you?' The response was 'we are a US Navy submarine very near you conducting a test and we very much appreciate you altering course so that we may continue. We never saw any sign of a sub, now wake, periscope. About 30 minutes later they called us on the radio, thanked us, and said we could continue on our original course... and 'have a pleasant sail.'


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[alctel]

The Canadian Navy has 4 diesel subs

[steve0h]

Originally Posted by MBWhite

Can you tell me about how they sound? I've never heard one, or even seen one operating.

To find a Trident, you listen for where the noise isn't - they are so quiet, they absorb background noise and create a noise shadow. Of course, being so quiet, if you get close enough to see the shadow on sonar, they already know you are there....

[s/v Beth]

Originally Posted by W3GAC

Us Navy only had one diesel sub left on their fleet 10 yrs ago. It was just used to test new sub gadgets and had an 'after market' extended/ hollow nose whose inside could only be accessed via diver and high pressure sea door. It was the Dauphin and based in San Diego and only ventured out to the deep trench off SD and back. Takes 4 hrs to get way down deep & and about same coming back up if following safety procedures. I was on it while it was dry docked on San Diego and company I worked for at the time had had some of it listening devices/ technology tested by the Dauphin. I never heard it running on the water. But based on what I know about nukes... you wouldn't hear any mechanical noise as it passed by... nothing... maybe just some bow wake splash if moving at fast cruising speed surfaced. In 20+ years of cruising wife & I have had two sub encounters. Once one way to St Thomas and in abt 7,000 ft deep water (the trench) we suddenly saw 'football stadium' lights suddenly cone on abt 1 nm from us. We could see a big cargo type ship with several very very big/ strong cranes that was holding a very big sub in position and conveyor belts were lowering supplies onto/ down into the sub while and crew were coming up out of the sub with their duffel bags and (new?) crew were going into the sub at a different deck entrance. about 15 minutes later the cranes disengaged and all the light went out. I was told later we witnessed a resupply & crew change. On a Galveston to Tampa non-stop straight line across the Gulf of Mexico, we suddenly received a call on ch 16... 'Sailboat approx position... this is US Navy'. They wanted me to deviate from my course 90 degrees... NOW!' Of course we did, but since we couldn't see any ship or airplane anywhere, my Curiosity got the best of me and I had to ask 'where are you?' The response was 'we are a US Navy submarine very near you conducting a test and we very much appreciate you altering course so that we may continue. We never saw any sign of a sub, now wake, periscope. About 30 minutes later they called us on the radio, thanked us, and said we could continue on our original course... and 'have a pleasant sail.'
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This and distress calls sound like a good reason to keep VHF on 24 7. I guess even old farts can learn a few things.