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-   -   Helm balance close-hauled and beam reach (http://www.sailnet.com/forums/seamanship-navigation/78964-helm-balance-close-hauled-beam-reach.html)

MarkSF 09-20-2011 10:03 PM

Helm balance close-hauled and beam reach
 
This Sunday sailing close hauled in 20 knots apparent I found a sweet spot I haven't before. She was heading up really high, moving nicely, and the helm was totally neutral. In fact I let go of it for a couple of minutes and she stayed right on that point of sail. This was with 100% jib, full main, both sheeted in hard. Two other boats were nearby and weren't pointing nearly as well so we left them behind. Nice!

But then when we had to head slowly down to a beam reach, and despite easing the jib and main, we got quite a lot of weather helm. I tried easing the main till it luffed and the weather helm didn't really go away.

I have taken to setting the solid boomvang, when the main is first raised, by sheeting the main in hard while close hauled, then tightening the boomvang until the slack is just going out of the line. This way the boomvang will come into effect when I bear away.

I have heard contradictory things : that use of boomvang on a beam reach flattens the sail, reducing drag and weather helm, and the opposite - let the boom rise to spill out some air.

So how to use it, and how do I make the helm more neutral on a beam reach? Please bear in mind that I don't have a traveler.

Faster 09-20-2011 10:31 PM

If the main is at the point that it's fully luffing it should be fair to presume it's not contributing to any helm forces anymore.. so the source of the pressure must be something else.. hard to imagine at that point that it's still vang-related. However if by luffing you mean a large bubble at the luff, then the leech may still be driving hard and causing your pressure..

Your adjustment procedure sounds OK to me but I generally will ease the vang from that close-hauled-no-slack position as we bear off... I think that's often more vang than you'll want off the wind. And 20 knots is a fair whack of breeze... you're going to be pretty powered up in a close/beam reaching situation..do you know what the rudder angle was? Was it extreme or was there just a lot of pressure on the blade?

It's good that you've got a decent vang, esp with no traveller.

WDS123 09-20-2011 10:44 PM

It is unusual to be able to trim for neutral helm hard on wind but not while reaching. Reaching is usually the easier course to trim.


Thoughts and possibilities

1) Sea State: were the seas favorable upwind for neutral helm vs. Unfavorable on the reach ?

2) Beam reach Trim: it sounds as if you were way overpowered, but on the reach all that should have done is got you to hull speed ( unless you were trying to surf ) How flat were your sails ? Outhaul, cunnigham tight ? Jib cars set for flat foresail luff ?

3) Vang Sheeting: as a general rule reaching and downwind, vang on = power, vang off = depower. It sounds as if you have a good sense of what your vang does to the main luff and boom angle, so a bit befuddled on this aspect.

MarkSF 09-20-2011 11:18 PM

It is unusual to be able to trim for neutral helm hard on wind but not while reaching. Reaching is usually the easier course to trim.


"Thoughts and possibilities

1) Sea State: were the seas favorable upwind for neutral helm vs. Unfavorable on the reach ?

2) Beam reach Trim: it sounds as if you were way overpowered, but on the reach all that should have done is got you to hull speed ( unless you were trying to surf ) How flat were your sails ? Outhaul, cunnigham tight ? Jib cars set for flat foresail luff ?

3) Vang Sheeting: as a general rule reaching and downwind, vang on = power, vang off = depower. It sounds as if you have a good sense of what your vang does to the main luff and boom angle, so a bit befuddled on this aspect."

The sea state was probably dead on the bow while close hauled, and from the 9-10 O-clock direction when reaching. All this is on a port tack.

The sails weren't very flat, the outhaul was a little loose I noticed later, and the cunningham was not in use.

I am not sure I have the jib cars perfectly set yet. I watched the jib as I headed up that day, and it all seemed to luff together. The top maybe slightly before the bottom.

Both sails are brand new and I'm still figuring how to use them. Pretty happy with the pointing ability though.

I think I was confused as to the effect of boom vang. It sounds like, from your post, to depower on a reach I should ease it. I was assuming that tightening it would flatten the sail and depower it. Now I see that tightening it tightens the leech and powers it UP, at least when reaching and running. Is this correct?

I think that "bringing the boomvang sheet back to the cockpit" is going to be moved up to the top of the things to do!

MarkSF 09-20-2011 11:26 PM

Quote:

Originally Posted by Faster (Post 777559)
If the main is at the point that it's fully luffing it should be fair to presume it's not contributing to any helm forces anymore.. so the source of the pressure must be something else.. hard to imagine at that point that it's still vang-related. However if by luffing you mean a large bubble at the luff, then the leech may still be driving hard and causing your pressure..

Your adjustment procedure sounds OK to me but I generally will ease the vang from that close-hauled-no-slack position as we bear off... I think that's often more vang than you'll want off the wind. And 20 knots is a fair whack of breeze... you're going to be pretty powered up in a close/beam reaching situation..do you know what the rudder angle was? Was it extreme or was there just a lot of pressure on the blade?

It's good that you've got a decent vang, esp with no traveller.

Yes, that's probably the case that the front half of the main was luffing but the trailing half was active - and very so with the boomvang tight.

The wheel was at about 1:30 to 2 O clock and there's 3/4 of a turn from dead centre to full over. I'm not sure how that relates to rudder angle.

The force on the wheel was very light but it always is on this boat.

WDS123 09-20-2011 11:44 PM

M,

Since you have no traveler, in heavy air, you'll need to play the vang a bit.


Downwind and reaching ( in heavy air ) , easing the vang will cause the boom to rise up and open the leech = air spilling out of sail, plus also making sail smaller.

Tightening the vang will have opposite effect......adding power while downwind and reaching



upwind - vang will tend to have opposite effect, vang on = flat depowered vang eased = more power......upwind heavy vang allows one to ease the mainsheet spilling air from leech but still keeping the angle of the luff the same,

puddinlegs 09-21-2011 12:47 AM

Reaching, ease your vang to twist off and depower the main. Play with it a bit. You'll figure it out pretty quickly.

Yorksailor 09-21-2011 02:45 AM

If she still has weather helm when you depower the main you need to reef both the main and the jib.

Phil

nolatom 09-21-2011 09:51 AM

I'd think you'd reef the main but not reduce the 100% jib. With a fixed keel, you're not going to change CLR much, so you have to move the Center of Effort forward to get them closer to each other.

I still think it's weird, though, to be so balanced on the wind but so unbalanced reaching.

GeorgeB 09-21-2011 11:43 AM

Mark, out of mild curiosity, what was your heel angle when you were experiencing excessive weather helm? As said earlier, try easing the vang to depower the main. This raises the boom tip and puts twist in the sail. On boats with travelers, you would be lowering the traveler instead, which changes the angle of attack instead. You will definitely want to route the vang back to cockpit. May I suggest you terminate it in a cam cleat instead of a clutch or Spinlock? I find that the line runs through a clutch much too slowly. There will be a time (like broaching) when you want to release tension immediately. Part of the joy of new sails and rigging is “dialing in” the boat. Great excuse to go joy riding around the Bay. We’ve been laid up most of the summer with a broken stem fitting so I am jealous – looking for another winch monkey?


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