Tapping, Knocking Sound from bottom of Hull

[bazzer]

John, I too have a similar noise to yours, I would describe mine as a crackling sound, a bit like rice crispies. I checked everything, from the electrics, to water running from a leaky tank, and yes I even thought it might be the keel about to fall off. My smart son, just home on the boat from college, googled for a short time and came up with the answer, Snapping or Pistol Shrimp. Here in San Diego they are widespread as they are worldwide. They "shoot" a air bubble from one oversized claw to stun prey. The US Navy says they are responsible for a large amount of the background noise in the worlds oceans. So maybe this is what you are hearing.
Bazzer

[zeehag]

the tropical banging sound differs from the clicking sound--the clicking have been known to be krill, crabs, and other sea life growing and feeding.
there is a fish with a hard head, locals call it a toro fish--it will hiunt fishlets up next to th eboat hull and catch the fish by ramming your hull
there are puffer/blow fish of different varieties which eat the oysters and barnies of fth ehull--makes a pop sound like a bang noise.
there are red snapper, or pargo , which also eat the gowth off boat hulls...that also makes a pop or bang sound.
the sound most like a bang is the toro bagging dinner between your hull and his mouth, as his head hits the hull...is why they have such hard heads...toro is a jack fish that looks a lot like a yellow tail tuna, but with differently shaped head.

[Pacific]

Originally Posted by bazzer

John, I too have a similar noise to yours, I would describe mine as a crackling sound, a bit like rice crispies. I checked everything, from the electrics, to water running from a leaky tank, and yes I even thought it might be the keel about to fall off. My smart son, just home on the boat from college, googled for a short time and came up with the answer, Snapping or Pistol Shrimp. Here in San Diego they are widespread as they are worldwide. They "shoot" a air bubble from one oversized claw to stun prey. The US Navy says they are responsible for a large amount of the background noise in the worlds oceans. So maybe this is what you are hearing.
Bazzer

THANKS!

[Rum Sunday]

What did you find out? I have the same thing going on except not a sailboat

[thomm225]

Sometimes it's just the waves slapping the hull......

[rwidman]

I once spent much of a night trying to track down a mystery noise that seemed to be coming from my hull. When we left the marina the next morning, the noise disappeared.

That noise could be coming from fish and other sea creatures or it could be coming from a dock or another boat. Sound travels really well in water.

[Manateeman]

The Jedi knows. It is the Kraken.

[Bullshooter]

Wait a sec, have you seen your wife around lately? I hope she didn't fall in!

[TooCoys]

Originally Posted by rwidman

I once spent much of a night trying to track down a mystery noise that seemed to be coming from my hull. When we left the marina the next morning, the noise disappeared.

That noise could be coming from fish and other sea creatures or it could be coming from a dock or another boat. Sound travels really well in water.

We call them "knock knock fish". They have long bodies with big eyes and carp like mouths and they sit at the water line and wiggle their heads back and forth eating the algae off the docks or your boat.

[Cheechako]

Those tapping shrimp are edible......