'Snap crakle and Pop' noise from under hull?

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Anthony

Anthony

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\'Snap crakle and Pop\' noise from under hull?

I am sure this has come up before but I cant find it in the archives; here in the med (spain) we often get a loud (well very noticable) crakling / popping noise, mainly at night that comes from all around under the hull, its like floating in a bowl of rice crispies!

We are not he only ones, and the general consensus from others in anchorgaes / marinas is that is it some sort of little creatures eating of the bottom even though Olli has a clan bottom :-) ).

Does anyone know what it actually is? Whilst I am prepaired to believe that it is creatures, I cant imagine anything small making that much constant noise, but yet I can never see anything under the hull.

Maybe I just have to much time now we are cruising, and should find more important things to ponder... ;-)

Thanks

Anthony
 
Re: \'Snap crakle and Pop\' noise from under hull?

This noise can also be heard underwater when diving off reefs and when anchored close to. Its not restricted to night time. I personally suspect (but do not know for sure) it is crustacians moving around.
If anyone else has definative evidence it is something else - it would be good to know.
JOHN
 
Re: \'Snap crakle and Pop\' noise from under hull?

Sounds bad to me. This is the final stages of (tertiary)osmosis - the sounds are the overstressed glass fibres snapping under the enormous pressure caused by the fluid bubbles that are growing in your hull. There's nothing you can do about it. Sorry to hear the news.

Of course there is always the possibility (if your boat is wooden) that you may just be hearing shrimps talking to each other...
 
Re: \'Snap crakle and Pop\' noise from under hull?

Anthony
I too have the same problem in Greece. I decided that it was caused by barnacles that I'd picked up on the prop and prop shaft, and some on the keel foot where the antifouling hadnt been applied. In my case I only realy heard them at night which fits with it being nocternal crustaceans.
Last week I did snorkel under the hull and scraped of a good proportion of what I could see and the noise seems to have all but stopped ...
 
Re: \'Snap crakle and Pop\' noise from under hull?

It happens frequently on the US east coast, particularly in the ICW. There it is krill (small shrimplike animal) feeding on the slime on the bottom of the boat. I assume it is something similar in the Med. If not it could well be the terminal stage of tertiary osmosis snapping the glass fibres, but I wouldn't wish that on anyone.
 
Re: \'Snap crakle and Pop\' noise from under hull?

Hmmm, well although Olli is GRP, she is 'gel shieled'ed and has no signs of osmosis, and others including on a brand new HR40 also hear the same noise, so (for my own sanity if nothign else!), am going to go with the shrimp talking to each other / krill dinner time theory.

Had a dive under her the other day, no barnicles anywhere, not much slime either (only antifold a few months ago). Maybe they are actually eating the antifoul ;-)

Although Olli welcomes pets I am not sure she is happy with creatures pecking at her bottom, even if it does help to keep it clean....

Anthony
 
Re: \'Snap crakle and Pop\' noise from under hull?

I had a similar experience on a chartered yacht off Sicily last year in spring. Rather than rice cripsies, it sounded more like electrical disharges. The boat was a new Benetau and I rather suspect that osmosis was NOT the cause. The charter company seemed to think it is due to electrostatic charging of the hull during sailing and discharge at night. I am not sure of this explanation, but I am passing it on to you.
I have never heard anything like it on our boat here on the south coast.
 
Re: \'Snap crakle and Pop\' noise from under hull?

It happens from time to time on the Australian coast. Generally believed to be crabs rooting.
 
tertiary osmosis

This is really bad news, I think my echo sounder must have it and also sometimes my VHF, should I write them off?
 
Re: \'Snap crakle and Pop\' noise from under hull?

Yes, we get it too ......and we are steel. Must have caught that bloody osmosis thing from that plastic boat we were moored next to!
 
Re: \'Snap crakle and Pop\' noise from under hull?

I used to dive a lot in warm waters, many places produced the electrical sound you describe. The were alleged to be shrimps and crabs doing their stuff. The noise was almost constant and not confined to night. Treat it as one of those delightful noises of the sea.

Pops
 
Re: \'Snap crakle and Pop\' noise from under hull?

It's the sound of propellors, some distance away, being transmitted through the water. It's always more noticeable at night as it is generally quiet and the hull of your boat acts as an amplifier.
Most people who have snorkeled at some time have heard it, usually from mobos passing a few hundred yards away. The engine noise is transmitted through the air and the prop noise is transmitted through the water.
 
Re: \'Snap crakle and Pop\' noise from under hull?

Like [--word removed--] it is, Most people can tell the difference between snap crack pop type sounds, and props. You've obviously never experienced it, so why comment?
 
Re: \'Snap crakle and Pop\' noise from under hull?

ah ... you made my day reading this ... picturing you stressing over one of the joyful sounds of being in a marine environment!
 
Don\'t be so b****y rude

Brendan, it may be that even your best friend wouldn't tell you this, but I've noticed that lately you've become more and more pompous and rude with people posting here. You also seem to have set yourself up as the self appointed Forum moderator.
If you can't be polite then don't bother to reply to anything I post as after this I will ignore yours.
Judging from the number of posts you have, you seem to have nothing else to do in your life but present yourself as some sort of expert on everything here.
Back to the subject in question, I have been observing this phenomenon for over 50 years and I can tell you, that is what causes it. That is why it is reported from all over the world, even in shrimp free places.
 
Re: \'Snap crakle and Pop\' noise from under hull?

It's fish feeding on the hull.

And I too have noticed that once a forumite has more than 12,000 posts then that forumites manner might change. /forums/images/graemlins/grin.gif
 
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