humming sound

Yet an other question from the newbie on the forum. When I get the 18 up to any sort of speed (that is fun) there is a pretty high volume humming noise. Does anyone know what is the source of this noise? In case it matters I have the black EPO rudders.

Humming sound. . . .its's a special Hobie sound that lets you know that if you go a little faster, you are cleared for take off!

Only kidding. Probably rudder cavitation, lots of posts on this. Fairly normal for Hobie's.

Start with rudder alignment, prop up the H18 on the beach so that you can lower the rudders and work on them. Take a piece of string and mark the measure from one front edge to the other at about 3" below the bottom of the hulls. Then walk the string to the rear of the rudders and do the same thing at the same height. The rudders should be toed out about 1/8".

While you are at it, check the rudder rake is the same.

Some folks take a sharp strong blade, (or buy the tool in the Hobie catalogue,) run it horizontally down the rear edge of the rudders, (like shaving off the back of the rudders,) so that you end up with a flat surface of about 3/16th". Rather less than more. My description is poor, and others may be able to describe it more accurately.

Cheers

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

There is an FAQ about rudders

http://www.hobiecat.com/support/tech/hum.html

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

I get the huming when im on a open reach with them down...

The humming lets you know your rolling, its when the humming stops that you must be alert. The noise is coming from your rudders and can be from the daggers but usually the rudders. I like the sounds you get at 15kts or higher, very high pitched. I would think the boat could talk to whales. Fair it out or live with it, even the high dollar white knight rudders cavitate and hum.

The sounds of speed. they can be caused by rudders or daggers while sailing with sound raise one dagger and if the sound stops you have found the offending noise maker or just crashed. Just kidding. by the process of elimanation you can find the noise maker. Then apply the corrective action posted in above posts if you want to fix (stop) the noise.

_________________
Tom & Nancy Page H20 803