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PostPosted: Thu Sep 13, 2012 9:11 am 
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Joined: Mon Oct 18, 2010 11:25 am
Posts: 26
Location: Glen Lake, MI
On the last few big wind days (15-18 mph, gusting well over 20) I’ve had a bad problem of rudder ventilation while on beam-broad reaches. Typically happens during a gust when the boat accelerates and the bows dig a little, and is rather unnerving to lose steerage at this speed and in waves (fresh water 1-2 foot chop).

After reading a few posts on the subject here I was beginning to suspect that my rudders were out of alignment – maybe toed out. So yesterday while I was out, I tried a few runs with the windward rudder raised, and while the issue was somewhat alleviated, it still began to ventilate on several occasions. When it occurs, I can shake the tiller to “re-attach” the flow, but sometimes that caused the cam to release and the rudder to pop up.

This spring I swapped the rudders from old-style castings + plastic rudders to new-style castings and EPOs that I refinished. At the time, I had the system pretty tight, and zero to less than 1/8” of toe in. It sails with just a slight bit of weather helm. Didn't have this problem last year, but I probably wasn't sailing it quite as hard.

So a couple questions: 1) What is the fix to eliminate this issue? Or does it just happen in these conditions and must be dealt with? 2) Or is it possible there’s something that I’m doing that may be causing it? Steering, sail trim, leaving my daggers all the way down? Any insight would be appreciated.

Thanks,
Peter


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PostPosted: Thu Sep 13, 2012 1:50 pm 
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You may be too far forward. As the boat accelerates in gusts, the bows are driven down and the rudder come up. Move aft and don't try to drive the bows down in higher winds.

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PostPosted: Thu Sep 13, 2012 4:51 pm 
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Joined: Mon May 09, 2005 10:25 am
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Location: Jersey Shore
To what level did you re-finish your EPOs? Did you wet sand them or just coat with epoxy? The surface definitely needs to be smooth. I'd say sand them with 600 grit wet/dry minimum. That's the first thing that comes to mind.

We had lot's of issues with ventilation on the H20 when sailing fast downwind and the 17 will occasionally ventilate when pushed really hard upwind. But on the 18, I've never really had any issues with it. The old EPOs would hum at high speed, but that's about it. My boat will occasionally switch to lee helm downwind, but it doesn't ventilate.

Also, if you're having loss of steering/ventilation issues, I'd sail with both rudders down, that way if one breaks free, the other will hopefully still be attached. The point about keeping the weight back is also a good one. Just because the boat is hard to pitchpole doesn't mean it should be sailed on it's nose.

sm


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PostPosted: Thu Sep 13, 2012 7:29 pm 
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Joined: Mon Oct 18, 2010 11:25 am
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Location: Glen Lake, MI
Thanks for the responses.

The rudders are pretty darn smooth. I wet-sanded up to 2000 then buffed with rubbing compound to make them shine. Trailing edges now have a nice clean taper and I haven't had any problems with hum.

Until just recently I'd always kept both rudders down - which remains my preference. The ventilation problem was what prompted trying it with just one. With both down it did seem like the rudders would fight each other when the boat speed really heated up, and as I recall it was usually the leeward rudder that broke loose. When that happened it didn't seem to matter than the other was still tracking cleanly - I couldn't steer the boat.

I've been trying to keep my weight back - but then maybe not enough. When out in the trapeze on a broad reach I'm typically straddling the rear cross bar, which is just about as far as my present trap setup lets me go. Should I be further back? The trouble is I'm usually out single handed, and then I'm probably a bit over-powered in the type of wind that this occurs. Haven't noticed the problem when out with crew - but that hasn't been very often this summer.

So what's the proper response when I does occur?

And on an aside - how important is it to raise the daggers when on a broad reach? I know that with the F18 boards there's risk of breaking them, but the H18 boards are pretty stout. Scrambling across the tramp to raise the leeward dagger hasn't been a priority in wind like this. Will they affect handling at all? I'm not racing so I'm not too concerned about additional drag if all they're affecting is my speed.

Thanks


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PostPosted: Fri Sep 14, 2012 9:10 am 
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Joined: Mon May 09, 2005 10:25 am
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Location: Jersey Shore
LeelanauH18 wrote:
When out in the trapeze on a broad reach I'm typically straddling the rear cross bar, which is just about as far as my present trap setup lets me go.


First question...why are you out on the trap on a broad reach? Are you running a spinnaker? If so, then I don't know what to tell you as I've never run a chute on a H18. If you're not running a chute, then there should be no reason to be out on the wire on a broad reach.

Quote:
So what's the proper response when I does occur?


Usually the only thing you can do is shake the helm back and forth to re-attach flow. Also sheet out to unload the helm. That's what we would do on the 20 at least.


Quote:
And on an aside - how important is it to raise the daggers when on a broad reach?


From a racing standpoint, raising the boards allows the boat to slip downwind and also reduces drag, so it helps in getting to the leeward mark faster. Raising the boards also helps keep the boat from flying a hull or "tripping over itself". Raise the boards in higher wind for more control downwind. In lighter wind, you can keep them down if you want to do the "wild thing". But nobody does that on an 18 since it's not faster than sailing downwind the normal way.

sm


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