Originally Posted by JPL
On a Bavaria
39. Suffering from very loud noises coming from inside the boom. They come and go based on wind strength and angle, it starts with a pulsating noise that gets louder and louder, with some metallic high tones. From inside a cabin
you'd swear there is an engine
I am new on this boat so I have to find my way around this without help from past skippers. First I tried to stop the flow of wind getting inside the boom by putting on the cover for the lazy bag that goes around the mast
. then I tried pulling reef lines to make sure they would not be too lose. Last I took a look inside the boom from its extremity and I see steel
cables running there, so I tried to muffle the sound with a rag placed on these. No effect. I can feel the topping lift vibrate, as well as these cables inside when there is a gust of wind.
The other yachts are quiet so something's wrong here. Any clue would be appreciated.
Any cable under tension can resonate. The sound can actually travel from the source to many unlikely places. It may seem like the boom is the source but the source can easily be somewhere else. I would guess the common solution is to stop the vibrating cable to muffle the source. Imagine the cables on the boat are guitar strings and the boom and mast are the guitar box, the sound can travel inside the box.
If the sound persists long enough you can quickly run around the boat putting your hand on every shroud
, the forestay, the backstay etc. to see if you can find the guitar string that is vibrating. If the sound is transient it may be tougher. It could also be a shroud
resonating above the spreader where you cant reach it to muffle it nut not resonating below the spreader.
I would certainly make sure all the standing rigging
is properly tensioned, followed by, as suggested already, loosening any running rigging
that is tight but not in use, i.e. topping lifts, spare halyards etc.
You may also end up getting a rigger to ride along on the boat.