Encounters of the Submarine Kind

[Seaworthy Lass]

Close encounter with a sub here. Heart is still pounding having briefly stopped.

4:15 am and I am on watch. Pitch black night. I hear the distinctive rumble of a sub on our port side. Five minutes later odd very bright lights pop up to starboard.

What lights do subs display?

PS I know I am edgy when catching sight of the rising moon then makes me jump!

[Sun and Moon]

Perhaps it was someone using a new toy to check out anchor performance.

[sy_gilana]

Subs display normal nav lights. G/R/W/W but, because of their configuration, usually on the fin, the size of the vessel might be mistaken, and sometimes the stern W is obscured by wash, therefore they may display a yellow or amber fl 1.5/s light. Its not always shown.
In addition some subs have a very bright locating light facing up on the casing. This will create a huge pool or glow, and usually is used in peacetime to indicate a surfacing sub, they probably know you are there, but want you to know where they are.
You mention rumbling, this would indicate a snorkeling or surface running diesel boat. The snorkeling one will sound more intermittent.
By their nature they are stealth weapons, and it is rare to encounter one, and almost impossible to encounter an AIPS or Nuc boat.
If you suspect a sub is near, make your presence known by noise, Engine, Gen, or echo sounder.

The boat should move away.

If you really want to have some fun, put on some Jimi Hendrix and put a speaker against the hull.

[MBWhite]

Here's a cut and paste that seems to cover it well:

Submarines have 5 primary navigation lights, though not all are used on the surface while in open ocean. The 3 primary lights are the Rudder (white light), Port (Red) and Starboard (Green). Additionally, a flashing yellow light is set atop one of the primary masts - this is a known warning to other vessels that the vessel is a Submarine.

The yellow light is used because at night, submarines are nearly impossible to spot; it's even difficult to maintain good orientation if you're topside and on deck at night while underway. Submarines also are much lower in the water than a traditional ship. Since a submarine's hull above the water only represents a fraction of its true size, knowing the vessel is a submarine lets approaching vessels know to steer further clear of the submarine because it is much bigger than is seen. The other lights are traditional.

In port or at anchor offshore, a Bow light on the Bow mast is lit at night - it isn't used while underway.


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

[Seaworthy Lass]

Originally Posted by Sun and Moon

Perhaps it was someone using a new toy to check out anchor performance.

I can report it is still there and looking very appropriate for December with the roll bar faintly glowing red and green .

[Seaworthy Lass]

Thanks Gilana and MBWhite.

The sound was a very deep rumble. Not the type of sound ferries and tankers make.

The lights seen were very bright and just popped up. Faintly orange, or at least yellow. One above the other. Not flashing. No red / green lights at all. Impossible to judge distance well, but I would guess several hundred metres away. Less than a nm.

The did not fade into the distance as lights of passing ships do. They just went out again.

Scared the hell out of me.

[JPA Cate]

Did you get a radar return from it?

[skipmac]

I saw a sub on the surface once at sunset just departing the VI headed north. Saw a very bright, yellow rotating light (like used on tow trucks in the US) maybe 1/2 - 3/4 mile off. Could not remember what the hell a yellow light was and asked my mate to bring up the copy of Chapmans to look it up. Glanced away for a minute and when I looked back it was gone. Disappeared so quickly I wondered if I had really seen it. Spooky.

[Seaworthy Lass]

Originally Posted by Ann T. Cate

Did you get a radar return from it?

By the time I turned the radar on the lights had disappeared and there was nothing.

We occasionally see subs on the surface about a nm or two away, but nothing this close.

[IdoraKeeper]

We see them on the surface frequently. The ones up here are large.. we see them on the surface only because of their own rules. They are closely and effectively protected. In the old days they were accessible in that you could sail right up and wave at the guys on the sail..they would wave back, glad to be home. Now we must stay far away. These are awesome weapons owned by the citizens of our country...one can hope for better days.

[s/v Beth]

Sea Lass, I bet it was from the eastern block, they seem to be a lot more spooky. Ours here in the sound (as Idora mentions) have lots of rules so they don't come by that close. I think I was funny we were talking about this only this morning. I think they know the exact inch your boat goes to, and maybe they like to stalk you a bit. (Kinda like our Homeland Security) I don't think turning on stuff makes any difference, but it does make you feel better. (At night I will turn on the deck light if I feel like something is getting too close)

[Seaworthy Lass]

Originally Posted by s/v Beth

Sea Lass, I bet it was from the eastern block, they seem to be a lot more spooky. Ours here in the sound (as Idora mentions) have lots of rules so they don't come by that close. I think I was funny we were talking about this only this morning. I think they know the exact inch your boat goes to, and maybe they like to stalk you a bit. (Kinda like our Homeland Security) I don't think turning on stuff makes any difference, but it does make you feel better. (At night I will turn on the deck light if I feel like something is getting too close)

I assumed they were a bit bored and decided to play games . Didn't stop my heart pounding though.
Had there been a risk of collision, I didn't have enough warning for evasive manoeuvres and I suspect they were so close that neither would they if they were not already tracking me.

The little buggers! Rules and regulations are looked at a little differently in Greece.

The lights did puzzle me though.

[Lepke]

Of the US subs I've seen at night, they always have a rotating yellow light and normal running lights. All lights really close together. In the US there are submarine transit lanes near navy sub bases. Generally the subs stay in these lanes when near or on the surface. There are also naval operating areas that usually have posted notices when in use. Sometimes a Coast Guard vessel will close an area for sub operations that may be dangerous to the unsuspecting mariner. With small boat radar, the nuks show up as a small boat at distance. The old diesel boats had a bigger radar return, the deck was a better shape for radar and higher. I've seen several non US subs but never at night.

[Muckle Flugga]

All round flashing yellow is the standard COLREGS light for a surfaced submarine, along with normal nav lights. The various I have seen have always shown this configuration.

SWL, I am unsure why you state "the distinctive rumble" of a sub… I have not heard said particular noise. Sounds like you have several times? If super bright lights at night can you be certain it was indeed a submarine? It almost sounds like a fishing vessel or tug, with massive diesels. I would have thought a sub pressure hull would mask the noise, plus the fact that military craft such as that are specifically designed to be a "silent service" massive throbbing noise doesn't sound like a useful feature of a supposedly stealthy weapon…

[Seaworthy Lass]

Originally Posted by Muckle Flugga

SWL, I am unsure why you state "the distinctive rumble" of a sub… I have not heard said particular noise. Sounds like you have several times? If super bright lights at night can you be certain it was indeed a submarine? It almost sounds like a fishing vessel or tug, with massive diesels. I would have thought a sub pressure hull would mask the noise, plus the fact that military craft such as that are specifically designed to be a "silent service" massive throbbing noise doesn't sound like a useful feature of a supposedly stealthy weapon…

I did not actually see anything at all when I heard the deep (ie low pitched) rumbling. It was loud enough to hear, and much more so to port. It was not a "massive throbbing". It was nothing like any diesel I have ever heard and I have now spent a fair chunk of my life on the water.

I termed it "distinctive", as "sub" was my first reaction when I first heard it, not "a boat is close with no lights on". Possibly the fact that we had passed through a "Submarine exercise area" about 10nm back influenced my reaction.

The twin bright lights (one above the other and low to the water) appeared to starboard and behind me maybe 5 minutes later. A warm colour, almost orangy. They disappeared abruptly. Nothing other than the lights seen with binoculars.

That's about the best description I can give. If not a sub, maybe some sort of military vessel?