Help with deciphering soft knocking sound

[TrentePieds]

Yep. My beloved has seen 'em too. In Codfish Cove on Jedediah Island I think we were, and there hadn't been a drop of likker aboard for days. MB SWEARS that some fish was picking grass off our bottoms!

TrentePieds

[sartorst]

I traced a random popping noise to my hull which turned out to be some small fish that were sucking something of the bottom

[FSMike]

I once solved a similar problem by emptying the wine bottles that were stored lying down in a locker.
Or I (hic!) think I did.

[Cadence]

Originally Posted by FSMike

I once solved a similar problem by emptying the wine bottles that were stored lying down in a locker.
Or I (hic!) think I did.

A little humor is great. I don't drink wine do beer cans make the same sound?

[a64pilot]

Originally Posted by sartorst

I traced a random popping noise to my hull which turned out to be some small fish that were sucking something of the bottom

I often hear a crackling sound, sounds like Rice Crispies that I think are shrimp.
Did a bad thing and had a new steel boat owner thinking that crackling sound was from hydrogen bubbles busting, from electrolysis on his steel hull.
He got so worried it took awhile to convince him I had the same sound on my plastic boat


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[Cadence]

Originally Posted by TrentePieds

Yep. My beloved has seen 'em too. In Codfish Cove on Jedediah Island I think we were, and there hadn't been a drop of likker aboard for days. MB SWEARS that some fish was picking grass off our bottoms!

TrentePieds

Cheer up! Save a haul out.

[ramblinrod]

Originally Posted by challis0124

I am not sure where this post belongs because I'm not sure exactly what the culprit is, so I'm hoping someone here can shed some light.

I am currently on an Island packet sailboat at anchor in an area with strong current and tide shift. I just noticed this evening there is a soft rhythmic knocking coming from somewhere on the boat...I can't pinpoint its location it sound like it's everywhere and nowhere. But it's continuous. Every few seconds it knocks 5 times then stops for a few seconds and starts up again.

I don't know if it's something on the deck( though I have checked all rigging and nothing that looks or sounds like this.) I live aboard my boat so am very attune to her sounds. I don't think it's anything on the engine, though I have heard prop shaft could cause something tho I'm not sure that's it either...maybe anchor chain ( though I doubt it). It almost reminds me of a woodpecker

Maybe a ghost

Any thoughts or if you have ever experienced this ? Much appreciated!

Cut a piece of hardwood about a 1" x 1" x 1' long. A piece of dowel or broom handle will do.

Hold it to your ear and then touch it to various parts of the boat as you move for and aft and side to side. When you near the culprit, the sound will be much sharper and louder.

Give a special look at anything that hangs or swings/rolls. (Closets, wet locker, gimballed lights, hammocks/canned foods, candles, wine bottles, tools, etc.)

Ramblin Rod
Marine Servive Provider
About Sheen Marine

[IolantheSF]

Had that problem on my Atkin Thistle. The "thonk, thonk, thonk" was only audible in the v-berth, so only heard while we were trying to sleep. Checked all the halyards - nothing. Ear on the mast - nothing. Went out on deck many times in the wee hours - nothing. One day, I'm sitting in the cockpit and i hear "thonk, thonk, thonk" at the exact same rhythm. It was the tiller hitting a stanchion. The cord tying it still had about an inch of slack in it. The hull was working like a musical instrument carrying the sound the full length of the boat to where it came out in the v-berth.