Swing Keel Buzzing

[roril]

We sailed my friends 1994 MacGregor 26S for the first time this week and I noticed a light buzzing sound coming from the swing keel as we got up to speed. 4-5 knots. This normal?
Thanks

[BOAT]

It's the cable that raises the centerboard going through the water. My A23 did the same thing. If you play with the centerboard raising crank you can actually tune it like a guitar. Lots of fun.

[THE CUSCUS]

Its an audible indicator of your speed. You should hear the sound at 9+ knots, surfing down a wave!

[BOAT]

9 knots! That old pig of a boat I had (My Aquarius 23) would not get 9 knotts with the Queen Mary pushing it! (But is was strong enough to put a pretty good dent in the Queen Mary!)
She was one fat bottom pig. (And SLOW!) But VERY STIFF!

[THE CUSCUS]

Well, I forgot to mention the 25knot winds from dead astern, the un-reefed main and jib, and the occasional, very abrupt roundings up. We made a 45 mile trip in alittle over 7 hours! Yeah the cable was "screaming", not just humming. It was quite the ride.

[reastmure]

I've heard the humming as well in a friends '80s Mac 25. Freaked me out as it was the first time I had been out in a Mac before I got my M. The greater the speed,the louder the hum!

[seahouse]

Unknown to me at the time, windsurfer centerboards (high aspect ratio) vibrate and hum when you get moving at a good clip (and there’s no cable). The first time I heard it, it was such a spooky sound that I thought that a torpedo was surfacing underneath me or something! Made me go even faster to get away from it.... but it was chasing me!!!! Yikes

Remember when windsurfers held the speed record for quite a while (ten years?)

Hey Crikey - are you looking to see if you can somehow go fast enough to make your daggerboard hum.

-B.

[Crikey]

Hey Crikey - are you looking to see if you can somehow go fast enough to make your daggerboard hum.

Bubblehead!

[roril]

Thanks for the info. I will start tuning it next time out,.

[topcat0399]

Hehehe

The first time we put our boat in the water and we are total newbs ....its 2 am full moon wind finally picks up and boat starts to really move for first time.

This sound started... admiral and I look at each other shes starts freaking and I'm acting like - its nothing. But inside I'm like.... WTF????? Power station over yonder 3 miles away humming? Project ELF we are receiving it somehow? World coming to and end? Lockness Monster?? WTF??????? WTF??????? WTF????

Admiral is looking around yells - its the BOAT!!!! Its getting LOUDER!!!!!

And I'm still honey: Its. Nothing. I'm .....sure..... (WTF???WTF???WTF????)

Finally occurs to me that we have a giant guitar string stretched out under the boat being played by water pressure. Oh thank god we aren't going to sink 5 miles from shore on our first trip. I hope.

Very disconcerting to the uninitiated!

Now its my speedometer!

[TIMBOAT2]

A small amount of slack in the cable will stop it if it is all the way down.

[TheJoe]

I was annoyed by this noise the first few times out. Now I get super excited when I hear it.
River sailing sucks sometimes.

[FinallySailing]

It's supposed to be a normal phenomenon on many boats, related to vortex shedding at the centerboard. I've never heard it on mine, though. The faster I get the louder the children scream