DaySailer.org Forum

Hello there,

On my last outing I noticed a pretty strong vibration in the tiller handle on my DS III in about 10-12 mph. There was no correlating vibration in the sails, but it was happening both down and upwind. I did notice some centerboard action when downwind, but have read that could be common? I have also read the centerboard "eye" can get routed out, but not having issues raising/lowering. Has anyone experienced something similar?

TIA,

BD

Your vibration could be from the rudder, or secondarily transmitted from vibration elsewhere.

For the first, check your rudder profile. Is it smooth or is there a reason to assume the rudder might create turbulence? If it does, that can set up vibrations.

Next, same for the CB. On a foil, it's the trailing edge that sheds vortexes and causes vibrations. I cleaned up my CB and never had vibration issues since.

I used 3M High Strength Marine Filler to add material to both leading and trailing edges.

Minimal, quick fix to the original "profile" on my CB. The edges were pretty banged up, and instead of just smoothing them, I added a bit more material as indicated. The CB has stopped fluttering/humming, still fits into the trunk and doesn't exceed max width under class rules (although, if I wanted to race under those rules, I'd buy a "real" CB to be competitive).

There should be a thread started around 2011 where I describe the process in detail.

I'd leave it. That way you can always say your boat is "really humming along!"

Sorry, couldn't resist the bad pun Good luck with the fix....

On catamarans it was quite common to have rudders hum at high speeds. There were two quick fixes, the first was to feather the trailing edge so it is sharp and the water passes evenly. The other option is to square off the trailing edge, with sharp edges. This one is easier to maintain. Nicks and dings and chunks missing will contribute to the hum. In that case I second GreenLake's suggestion of 3M filler. Dries very fast so you can sand and recoat to get the profile you are looking for.

Don't "square" the edge at 90 degrees, make it just a bit of an angle, like 75 degrees. Makes it so one side is preferred and supposedly you don't get the alternating vortexes.