Vibration under sail

[Wally Boggus]

I have been noticing some vibration under sail on certain points of sail and it occurs around 4+ knots never below that. It is definately eminating from the bottom of the boat somewhere. It is an off and on sort of thing and is really obvious in the cabin through the floor boards. I keep the the trany in reverse so don't think it is the prop. Next time out I plan to feel the shaft to see if that might be the source. I'd hate to have to dive right know as the water is pretty cold but I may have to as it is driving me crazy. Anyone have any other ideas?

 

[SteveC]

I had a similar experience on my 37.....

accelerating when coming off a wave, I would get a vibration only at 'higher speeds'. What it eventually turned out to be was a loose cutlass bearing and my fixed prop. The fixed prop would not move(in reverse) and when the boat accelerated, the 'loose bearing' would allow the shaft to rapidly move producing vibration. What I did was replace the bearing and get a feathering prop. One or both of these eliminated my problem. I suspect that the main culprit was the bearing. The only other things I can think of is rudder play or you may be dragging something else on the rudder/keel (lobster pot, etc.)

 

[julian]

hummin'

called the Hunter Hum. See archives. My own 310 hums at 4.5 knots+ and I think it is the rigging, the noise amplified by the cabin, like a soundbox.I feel that "she is on the cam" as a mechanic would say!

 

[Steve Cook]

Happy boat???????

I agree with what Julian has to say,My 1999 H310 has the same humming sound.I too feel it is from the rigging. I talk to Greg Emerson from Hunter and he too thought it was from the rigging.It seems to only happen at or around 4kts. boat speed and the boat just seems to be happy. Therefore, I believe the boat is humming because she is happy???I don't let it bother me any more.If you do find away of stopping it, Please let us know as it seems to happen with all 310's and 320's.Steve,s/v The Odyssey...

 

[Jim Logan]

humming rigging

My H33 doesn't hum (too slow?) but in my Hoby cat days the hum only started above 10 knots or so and you knew you were really moving by the amount of noise the rigging was making. Its probably vibration of the rigging, try a half turn tighter or looser and see if it changes the speed at which it happens or sound patterns.

 

[Wally Boggus]

Thanks guys...

Glad I'm not the only one. I read the archives and found that it could also be the topping lift so I'll check that also. I want too eliminate the possibility that it is something hanging off the bottom of the hull (i.e., rudder,shaft,strut,keel). Otherwise I can live with it if I know that it is just rigging or is just the sign of a "happy boat".