Egregious
Guru
Last week we were on the hook 3 nights and in marinas the rest.* When we were on the hook we would sometimes hear a strange vibration that was literally loud enough to keep you awake all night (one night it nearly did).* The sound seemed to emanate from the transom area but from the bottom of the boat, and was very loud at times.* Like a fast jackhammer in period and the tone never changed.* The strange thing about the sound is that it is loud aft and isn't heard forward.
I looked everywhere and could not identify any stays, rubbing furniture, canvass, vibrating pumps or anything else and could never put my hand or ear directly on the source of the noise.** What I did notice is that the noise seemed to correspond to the speed of the current -- never noticed it during a slack tide.* At first I thought maybe one of my rudders was loose and somehow was being acted upon by the current since our boat was being pushed against it by a string perpindicular wind.
But my final theory is this:* I use a 25' snubber which was pulled tight like a guitar string down into the water.* The force of the current caused it to vibrate like a guitar string and somehow the tone resonated from the bow hawse pipe back through the boat and wasn't "released" until it hit the transom.* That is the only way I can think of where the sound is audible in the aft cabin and not in the forward cabin.** I was going to shorten or remove the snub to see if the sound went away but didn't want to do that in the dark at 1AM.
Ideas?* My theory might sound strange but I've heard some bridle chafing that was truly unbearable when on a mooring ball, so I know vibrations can travel in strange ways throughout a boat's hull.
I looked everywhere and could not identify any stays, rubbing furniture, canvass, vibrating pumps or anything else and could never put my hand or ear directly on the source of the noise.** What I did notice is that the noise seemed to correspond to the speed of the current -- never noticed it during a slack tide.* At first I thought maybe one of my rudders was loose and somehow was being acted upon by the current since our boat was being pushed against it by a string perpindicular wind.
But my final theory is this:* I use a 25' snubber which was pulled tight like a guitar string down into the water.* The force of the current caused it to vibrate like a guitar string and somehow the tone resonated from the bow hawse pipe back through the boat and wasn't "released" until it hit the transom.* That is the only way I can think of where the sound is audible in the aft cabin and not in the forward cabin.** I was going to shorten or remove the snub to see if the sound went away but didn't want to do that in the dark at 1AM.
Ideas?* My theory might sound strange but I've heard some bridle chafing that was truly unbearable when on a mooring ball, so I know vibrations can travel in strange ways throughout a boat's hull.
