loud vibration?

I have a Hobie Cat 16. Whenever I get going fast at all I hear a loud vibration. At first I thought that it was the cables, but now I think it is coming from the rudders? Anyone ever have this problem? Thanks for any help.

That's the Hobie hum my friend.

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Marc...
1978 Hobie 16 Keoke, sail# 36 84

What he said, that's rudder hum. There are things you can do to reduce or eliminate it. 'Search' doesn't turn up much but if you sharpen the trailing edge of the rudder it seems to help.

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1990 "Formula 1" H16 (# 009)

Rudder Hummmmmm Very typical.

There is a FAQ solution: http://www.hobiecat.com/support/article ... h/hum.html

Sailing FAQ section: http://www.hobiecat.com/forums/viewforum.php?f=18

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

My first boat I bought does it. so loud, my son in law was ono the boat out on the lake and I was at the house 1000ft? from the boat and it cut through the air as if amplified. Just as loud at my house as I hear it when on board. It's a rather satisfying sound - never bothered me.

My 2nd boat has ZERO hum - stays totally quiet. I have to say - I think I prefer that now that I've experienced both.

My 3rd 16 - I haven't sailed yet, so I dunno, but it has fiberglass rudders. I was gonna move them to my quiet boat, but maybe I shouldn't mess with things since they're silent.

Thanks for the help! I am going to try and sand down the rudders a bit. If it doesn't work, oh well it doesn't bother me, I was just worried that something might be wrong.

Hi, I recently posted about my first sail with my '81 H16, which I refurbished/rebuilt but hadn't sailed in the 19 months since I bought it.
One thing I didn't mention was the noise the boat made. I rebuilt the steering system starting with sanding and painting the standard rudders, new cams and adjustment screws, shims of plastic between the rudders and castings to eliminate slop, bushings on the rudder pins, new upgraded spring/cup connectors where the tiller joins the crossbar, and I made sure to set it up with the correct toe-in angle, based on all I read here.
I had EXPECTED a hum when we got up to speed, but the noise was more like the groaning of a structural member failing in a building or airplane. Nothing broke or failed, and it wasn't really disconcerting, just surprising that I didn't get a hum.

One last thing, I also failed to give a BIG THANKS to Matt Miller for explaining a way to replace the dolphin striker rod. Thanks Matt!!!

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David

Hi I have a 1980 Hobie 16 which I bought (ok my dad bought me) back then and still have. I saw an article in the Hobie Hotline on the Hobie hum way back in the 80s or 90s, since I had the same problem back then, the boat sang like the whales. I know this problem is common at least with the white Lexan rudders, not sure about the other materials they use for rudders now. The solution, which worked for me anyway, is to sand the trailing edge of the rudders to a fairly sharp edge, to get rid of the rounded edge. You don't have to make them knife sharp but shave down the back radius to a smooth crisp edge. Use a sanding pad and sand wet, start fairly course then for finishing go fine to get a smooth finish. It is a easy fix to the problem. Never had a hum since, that is what almost 30 years now.

I had the hum as well. I used shims cut from margarine tubs to tighten up the slop in the rudders and have never had the problem since.

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Mims, FL

I loved the hum, It was always kind of a speed sensor for me. When it started to hum I knew I was in the groove, I never fixed mine, let it hum!!

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06 getaway -- always remember, man with both feet in mouth have no leg to stand on.

My 16 has the famous Hobie hum also-I like it- I feel like the boat is coming alive when it starts to hum.

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Mono slugs of various sizes and shapes
H 14 About 15 years ago
H 16 1982

Making Wake on A No Wake Lake!!!!!!

my favorite the rudder huuummmm! if it bothers you, you can trim the rudders to reduce the noise.

Back when a buddy of mine and I went out for the first time in some 20kt winds, we got flying on one hull and she started to hum. From then on, anytime we went out he would start yelling "moan baby, moan!" Once she did, we knew we were flying and in for a great day of sailing!

I still remember 28 years ago as a teen, watching a couple H16s on Lake Windermere, BC. Great high wind lake and when they were flying along you'd hear this neat hum from them when they accelerated. Now I know what it was!

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I have EPO's on my 86 H16...they hum too.