Weather helm is a phenomenon seen in sailing craft in which the boat has a tendency to turn into the wind when the rudder is not controlled. A slight amount of weather helm is actually viewed as a positive by sailors, who will “tune” their boats to achieve the desired level of weather helm. In contrast, lee helm involves a tendency to turn away from the wind, and it is generally viewed as dangerous and undesirable.
The amount of weather helm experienced in a specific craft has to do with how the boat is balanced. Some degree of tuning can be accomplished by altering the sails in ways which may be temporary or permanent, depending on the need. In other instances, weather or lee helm are caused by the structure of the boat, in which case the boat may need to be brought out of the water for modifications.
When a boat is underway, the tiller must be pulled slightly windward or “to weather” to counteract the effects of weather helm. As soon as the tiller is released, the boat will start to drift into the wind. Small adjustments can be made to the tiller as the boat is moving to address changes in wind speed and direction. Sailors must keep a close eye on the conditions they are sailing in so that they can quickly identify and respond to changes.
While a small amount of weather helm can be good, it can become a problem if it is excessive. If the tiller must be turned more than a few degrees, it turns the rudder so far that it creates drag which will slow the ship down. This is not desirable, especially in boats which are used for racing. With a new ship, a sailor may spend several weeks making adjustments and learning about how the ship handles to strike the sweet spot, the point at which there is just enough weather helm to be beneficial.
New sailors need to be aware of weather helm and the tendency for boats to move into the source of the wind so that they can learn to navigate safely and efficiently. Weather helm can be harnessed to get a boat moving smoothly and quickly, or it can create a situation in which the boat fights the sailor and is difficult to control. Experienced sailing instructors take their students through a range of sailing situations, both hypothetically and in real life, so that they will know how to respond to an assortment of conditions.