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Weather Helm

squash

Member
I was sailing today in 10-18 knots of breeze. Going upwind in the heavier stuff (15-18), I had a lot of weather helm, even when the boat was flat, and much more so on port tack.

I had my goose-neck as far back as I could get it, to the point where a sail tie wouldn't let me go back any further. I am sorry, but the boom isn't marked because it is not my boat, so I cannot tell you the exact measurement.

I weigh 140 pounds (wet).

What to do?
 

58984 EW

Member
I was sailing today in 10-18 knots of breeze. Going upwind in the heavier stuff (15-18), I had a lot of weather helm, even when the boat was flat, and much more so on port tack.

I had my goose-neck as far back as I could get it, to the point where a sail tie wouldn't let me go back any further. I am sorry, but the boom isn't marked because it is not my boat, so I cannot tell you the exact measurement.

I weigh 140 pounds (wet).

What to do?


Well at 18 knots you might very well have been overpowered at 140 lbs, but I'm curious to know exactly how far back the gooseneck was? You said the sail woudln't let it go back any further... does that mean you were up agaisnt a stil clip/grommet? If so, remove the clip and move back further. I'm guessing you were at about 15 inches, and you can/should go back more if you were experiencing a ton of weather helm.
 

beldar boathead

Well-Known Member
It will help if you had room to sit further back in the boat.

Fred
Actually you should sit as far forward in rhecockpit as possible. Front leg should be bumping into front of cockpit. That won't solveyou weather helm but it proper sunfish form

in the breeze you described and at your weight your goosenck should be around 17 or 18 inches from the front of the boom. BB
 

58984 EW

Member
Actually you should sit as far forward in rhecockpit as possible. Front leg should be bumping into front of cockpit. That won't solveyou weather helm but it proper sunfish form

in the breeze you described and at your weight your goosenck should be around 17 or 18 inches from the front of the boom. BB
Seconding Beldar's comments. Moving forward will keep the bow of the boat low and the stern high, creating a better, more effecient wetted surface area in the water. Move back only when your bow starts to bury in waves.
 

58984 EW

Member
Is the idea to keep moving the goose-neck back until there is neutral helm when the boat is flat?
Yes, that's the idea, although if you get much farther back than 18 inches it's time to think about other options (accepting that you have weather helm, or depowering the rig)
 

Edward Teach

New Member
Yes, that's the idea, although if you get much farther back than 18 inches it's time to think about other options (accepting that you have weather helm, or depowering the rig)
Newbie here. When you say depower the rig is that accomplished by letting the sail out until it luffs or turning more into the no-go zone?:confused:

Thanks,
Ed
 

ylojelo

Member
........and when you say 'back', do you mean moving the boom towards the stern so the distance (between the boom end and the gooseneck) is decreasing?
 

beldar boathead

Well-Known Member
........and when you say 'back', do you mean moving the boom towards the stern so the distance (between the boom end and the gooseneck) is decreasing?
No. Moving the gooseneck back on the boom means it is further from the front of the boom.

Depowering first entails tightening the outhaul and either he uphaul or Cunningham. Next you go to a jens rig and when that is not enough you reef also. Someone on the board will know where to point you to see what the latter two are and how to do them. They have a huge effect. BB
 

Wayne

Member Emeritus
Depowering first entails tightening the outhaul and either he uphaul or Cunningham. Next you go to a jens rig and when that is not enough you reef also. Someone on the board will know where to point you to see what the latter two are and how to do them. They have a huge effect. BB
The Jens Rig is described in the FAQ section of the Sunfish KB & FAQ at the top of this page. Illustrations can be found in The Sunfish Bible by Will White.

This video shows the more advanced Gust Adjust rig for accomplishing the same sort of sail lowering by a different method.




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Wayne

Member Emeritus
........and when you say 'back', do you mean moving the boom towards the stern so the distance (between the boom end and the gooseneck) is decreasing?
No. Moving the gooseneck back on the boom means it is further from the front of the boom.
I'm going to give BB a friendly nudge to change the reference from gooseneck to boom..., since the gooseneck doesn't actually move at all. What you are doing is sliding the movable boom in the stationary gooseneck to shift the sail back and forth.

The further back the sail is shifted, the stronger the weather helm effect will be. Conversely, shifting the sail forward reduces weather helm. However, you almost never want to enter the lee helm region or the boat won't point and helm behavior gets unpredictable in changing wind speeds.

In the weather vane model the sail is the vane's tail and at neutral helm the Center of Effort of the sail and the Center of Lateral Resistance of the hull and foils are balanced. In this position when a breeze hits the weather vane it doesn't want to point in any particular direction. As the vane's sail-tail is moved back, the weather vane wants to point toward the direction of the wind. The further back it's moved, the quicker and more strongly it wants to point into to the wind.

Helm is like the alignment of your car's steering, only it's a boat's tendency to stay on course. You want a slight bit of weather helm, but excess means you are having to over compensate with the rudder and that slows the boat.




[ame="http://www.youtube.com/watch?v=-WFtmOfORfg"]YouTube - Championship of Champions Gooseneck adj discussion[/ame]

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