Q&A - Weather helm

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Q. You removed your sailboat’s mast over the winter, and after stepping it this spring the boat doesn’t sail as well as it did last season. The tiller is heavy, and the boat keeps trying to point up into the wind, especially on a reach. What could be the problem?

Q. You removed your sailboat’s mast over the winter, and after stepping it this spring the boat doesn’t sail as well as it did last season. The tiller is heavy, and the boat keeps trying to point up into the wind, especially on a reach. What could be the problem?

A. When a boat constantly tries to steer itself up into the wind it’s experiencing weather helm. Although this isn’t a bad thing from a safety standpoint, too much weather helm makes steering tiring and frustrating. This and lee helm — when a boat tries to steer itself away from the wind — in most cases can be traced to problems with the rig.

To simplify what is happening, think of the boat as rotating around a central pivot, generally called the center of effort. On most boats this generally is near the point where the theoretical centerline of the mast bisects the boat. Sailing on beam reach with just the mainsail set, the wind acting on the main alone tends to push the aft part of the boat away from the wind; left to its own devices it would quickly point the bow into the wind. This is weather helm in the extreme. If only the genoa is set the reverse is true, and the wind will tend to push the bow away from the wind, giving lee helm. When both sails are set and balanced properly these turning moments cancel each other out and the boat sails in a straight line with a fairly light touch on the tiller or wheel.

If you are still getting weather helm with both sails set and pulling, this would suggest that the mast is raked too far aft. Loosening the backstay and tightening the forestay will cant the mast farther forward and should correct weather helm. Thus it follows that to correct lee helm you should loosen the forestay and tighten the backstay.

This cannot really be done while tied up to the dock. Sail the boat in a gentle Force 3 and make small adjustments to the rig as you sail back and forth on a beam reach. Don’t overdo it; just two or three turns on a bottle screw has a major effect at the top of the mast. You should be aiming for just a gentle tug on the tiller when the rig is correctly set.

Also, make sure your mast is upright and not leaning to one side or the other. A good way to check this is to unshackle the main halyard and release it until it just touches the toe rail adjacent to the after-most shroud. With the halyard cleated tight at this length lift it over the boom and see if it touches the same spot on the other side of the boat. If the mast is dead perpendicular then the halyard will touch at exactly the same spot. If necessary loosen the shroud bottle screws to adjust as required.

Sometimes weather helm isn’t the product of an improperly tuned rig. I once sailed on a boat where the mainsail was so old and worn that no amount of mast tweaking was going to get rid of the weather helm, so check your sails for wear. With your lips pressed against one side and a hand on the other there should be no noticeable blow-through. If there is, the sails probably should be replaced.