Centerboard noise

[Buddy]

I own a 1967 Mariner. I finally got her into the water late thisyear after many hours of repair.... starting to look good but I have a long way to go. What I need help with is the loud hum or noise coming through the centerboardtrunk created (I think) from the centerboard cable hitting the trunk. When Icalled the Rhodes dealer, he said this was normal; this can't be, for it takesaway from the peacefulness of sailing.Does anyone know how to eliminate or atleast reduce this noise?Thanks, Buddy

 

[Justin - O'day Owners' Web]

Humming

Actually - its pretty normal. What is going on is that as either the centerboard or its cable gets dragged through the water it vibrates. When the vibration hits resonant frequencies you get that hum.There's not really a lot you can do about it other than sail faster or slower than the resonnance points. I always sort of liked it - made me feel like I was going really fast.Justin - O'day Owners' Web

 

[Geof Tillotson]

We strove for that hum when I was a kid

Albeit on a diferent boat, a 40 foot centerboard yawl. But when that baby was tuned in and flying along that hum would start and the whole crew knew that we had her trimmed up perfectly.Just the personality of the boat. I have been on smaller boats that hum too, I've always liked it.Geof

 

[MArk]

Audio speedometer

My first boat was a Venture 17 with a 300# swing keel (SK). With tension on the cable, I could use the frequency of the hum to determine my speed.If you want to get rid of the noise, you can try locking down the centerboard and releasing the cable tension.Vortex shedding is a very accurate and reliable method of measuring flow. (see related link)

 

[Craig - Boston]

Our boat purrs like a kitten - we prefer to say

It is a good sign indicator of your boat speed thru the water. There are ways to reduce or cancel this moise.Justin was right. It is the SB cable resonating as it cuts thru the water. The best solution to date is to replace the cable with a plastic coated one. The change in properties does the trip and actually looks a little neater in the cockpit.But if you do not want to replace the cable (it is a pain in the arse to swage new connectors etc), yo ucan just coat the existing cable with a liquid rubber. Good Luck,Craig