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post #1 of 8 Old 07-10-2011 Thread Starter
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Sail trim techniques

We were out yesterday on a Cat 25 in bay/swell conditions & 15-20 mph winds. Had a great day, my first 'heavy weather' experience, (it's all relative-in higher winds I typically opt for windsurfing instead). With full main & jib I felt like I was struggling more then necessary. My question is: what is the next step? Do you automatically go first to reefing the main, or can you bring in the jib, or combination of both?
We had a downwinder back to port & ended up furling the jib & broad reach/ run on a full mainsail back, which worked well, but, I am looking for advice, is this optimal.
Any advice on sail trim theories for me to pursue?
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post #2 of 8 Old 07-10-2011
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I ususally do not reef until winds are in excess of 20 kts. If "weather helm" is an issue I'll let out the main a bit to move my center of effort back. VMG may even be better after the adjustment(also may have to bear off the wind a bit).

As far as down wind, you most likely had the right idea since the jib would be mostly blocked by the main.

This is my two cents worth, I am sure others will add more.

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post #3 of 8 Old 07-10-2011
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Before easing or reefing, flatten the main. Harden the outhaul to flatten the bottom of the main, bend the mast with the backstay adjuster or a babystay to flatten the upper portion of the man, and try hardening the cunningham.

Racers are also constantly adjusting the traveler, then the mainsheet to give the helmsman the feel they want.

Then try reefing the main and changing the headsail.

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post #4 of 8 Old 07-10-2011
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Ditto above mast/mains'l adjustments.

On my Cat 27', then next thing is to go to a smaller jib, and once down to the "working" 110% I'll start putting reefs in the main. With that, I haven't needed the storm jib yet, up to ?25-30 knots. (Yeah, I admit I probably overestimate wind strength.)

I'm of windsurfing background too, so I've got a bunch of foresails-a 150%, 130%, 110%, ~90% and a storm jib. Most real sailors would probably think that's over the top, but I like feeling like I have the right sail for conditions, and the foredeck work is kinda fun.
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post #5 of 8 Old 07-10-2011
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As mentioned above, before reefing, you need to get the sails as flat as possible. To do this, add a LOT of tension to the halyards, both main and headsail. Then crank on the outhaul for the main. If you have a back stay adjuster, make it tight.

If that doesn't work, then it's time to reef the main.

Get out there and experiment. There is no replacement for experience!


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post #6 of 8 Old 07-13-2011
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Also depends on which way you are going.

If your beating into 15-20, I'd expect the apparent wind to be peaking near 25. Would not be surprised if you needed to reduce sail. If you are headed the other way with the wind on your stern, the apparent maybe sub 15, and you can probably leave everything up. Just keep an eye on things when running, or you may find yourself unhappy if the true wind climbs unexpectedly, and you need to go the other way.

Headsail or main depends on the boat. Big 150 genoa, probably that goes first. Fractional rig with hardly any jib overlap, then probably the main reefs first. Every boat is a bit different, as others have stated, a bit of experimenting will help you dial it in. Enjoy
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post #7 of 8 Old 07-13-2011
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If you had a 150 roller furling out, I would have taken some of that in 1st..before touching the mainsail. then if you're overpowered, flatten the main, ease the traveler or put a reef in as others have said.

On the downwind leg home...( I did this last week) I hove-to took down the main and sailed home on a broad reach with the genoa. If I'm by myself..(or with non-sailors)...with my mainsheet on the cabin top, It's much easier, safer and relaxing for me to sail downwind with the genoa than try to gybe with the main...
( I'd have to put the auto-pilot on, leave the helm and sheet the main in to gybe)
I can control the genoa from the helm.

It's also very easy to roll in a little of the genoa..if I need to slow down, than head back to windward and reef the main.

Last edited by tempest; 07-13-2011 at 07:31 PM.
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post #8 of 8 Old 07-13-2011
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Early-on with my C25 I found that partially roller-furling/reefing the 150% genoa did more harm than good in a blow. Then I discovered luff foam, installed it, and now the genny behaves Much better when I take it in a bit. Less bagginess = greater control.

Also, these days I'm quick to use the mainsail traveler. I know, it doesn't look like its paltry amount of travel will do much, but it does help keep the boat upright and the rudder acting more like a steering device than a trim tab or diving plane.

For the downwind run, do you have/use a whisker pole for the jib? Wing-and-wing is fun (and it feels a bit safer in shifty winds when the boom is fitted with a preventer).

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