Mysterious Humming Sound

[scherzoja]

Originally Posted by Lightwave99

This is not a loud sound at all. It is a humming and you only hear it if it is very quiet and you put your ear close to the hull walls. But I agree, it has to be manmade. That is what we are trying to find out. Thanks.

Lightwave,

You stated a few times that you only hear the sound when you are down below, when it's quiet, and at night.

Have you ever heard this when on deck? If you only hear it when below, then the sound is likely traveling through the water and your hull is transmitting it into the atmosphere (of your boat, below deck).
Shrimp crackling noises around here can only be heard when down below because of the way my hull passes that sound into the hull. Step into the cockpit, no shrimp crackle.

What are the currents doing when the hum is present? Are there buoys in the area. Perhaps the water flow past the buoys' anchor rode causes a vibration sound. Perhaps it starts in evening and stops in morning because during that time, the water flow past one or more buoys.

Does the hum occur all night long or just in the morning and evening hours?

[Singularity]

Originally Posted by Lightwave99

Good idea, Ann. I will look into it. This seems to be taking up too much mental space! And all for solving the mystery of a little hum detected when we were relaxing during our wonderful Desolation Sound annual cruise. )

When the sound is heard below deck, either dunk an ear or the stethoscope bell into the water...presumably the water is noisy. As stated in earlier responses, you are likely sitting on a resonator. If indeed the water is noisy, I'd assume that the energy/harmonics required to make air inside a boat noisy to a gray-haired sailor's ear would be grievous to sea life.

Links to ponder if bored:
The Main Deck - Northwest Fisheries Science Center
Research and sea-going activities of the Fisheries Engineering and Acoustic Technologies (FEAT) Team
https://www.fisheries.noaa.gov/west-...science-center [contact info on website]

NOAA Ocean noise splash page:
https://www.fisheries.noaa.gov/natio...ta/ocean-noise

Otherwise, if you can somehow record the noise, and if the noise sounds like magma displacement, consider speeding up the recording 10 times speed to see if you might have detected some kind of new man-made device: https://youtu.be/y7g6dKncO-I

[Lightwave99]

This is not neurological or physiological. We only hear it through the hulls when we are on our boat and only heard it this year, 100 miles from the major "civilization" of Vancouver, though a bit closer to smaller cities, but still 50 or 75 miles away. So these sites are not applicable. Another sailor heard the same thing. As we do not hear it when we are off hiking or in our dinghies, we are obviously not carrying it with us (neurological or otherwise physiological like ear problems). Thanks for trying.

I think we should drop this subject now, as we are getting repeated suggestions of the same thing.

[Lightwave99]

Originally Posted by scherzoja

Lightwave,

You stated a few times that you only hear the sound when you are down below, when it's quiet, and at night.

Have you ever heard this when on deck? If you only hear it when below, then the sound is likely traveling through the water and your hull is transmitting it into the atmosphere (of your boat, below deck).
Shrimp crackling noises around here can only be heard when down below because of the way my hull passes that sound into the hull. Step into the cockpit, no shrimp crackle.

What are the currents doing when the hum is present? Are there buoys in the area. Perhaps the water flow past the buoys' anchor rode causes a vibration sound. Perhaps it starts in evening and stops in morning because during that time, the water flow past one or more buoys.

Does the hum occur all night long or just in the morning and evening hours?

We were only hearing it when in the boat, through the hulls, at night. Two locations about 15 miles apart. And it stopped abruptly about 4 a.m. each time.

[s/v Jedi]

Originally Posted by Lightwave99

We were only hearing it when in the boat, through the hulls, at night. Two locations about 15 miles apart. And it stopped abruptly about 4 a.m. each time.

Invite more people into your boat to find out if they hear it as well. The thing is that the article I posted claims it has never been recorded, i.e. it does not exist as a sound wave traveling through the air.

[JPA Cate]

Since two different people were hearing it on different boats at the same time in the same anchorage, I don't think it can be within the people themselves, the chances of that are vanishingly small.

It is not a loud vibration, and it is heard only below decks in quiet conditions, and at specific times. Because of those data points, I agree with Lightwave 99 that they must be man made, and traveling through the water, as whale song does. And that it is not whale song, because it is a single tone. Lightwave wrote that it is low pitch. If it is a 60 cycle buzz, he probably would have recognized that, so it probably isn't that. But it could be some sort of distant machinery which is turned off for x hours per day.

What we don't know yet is what that distant machinery may be.

Ann