by Bob Norson

Excessive weather helm can be exhausting of crew and ruinous of autopilots. It also places unnecessary strain on the rig and slows the boat down. Not that all weather helm is bad. A certain amount is better than the alternative. An unattended helm going to weather is of little concern. More embarrassing than harmful but lee helm, the tendency to fall off the wind can instigate an accidental gibe which in strong conditions can be quite destructive. Lee Helm is common and no issue in light airs.

How does it happen and what can you do about it? There is a point in your boat underwater that the boat pivots from. If you could look from above as equal force is applied in opposite directions from your bow and stern you would observe the one point that doesn't move, the centre of spin, the axis. That is your “Centre of Lateral Resistance” or CLR. (Figure “C”)Vessel trim can effect the location of the CLR somewhat. The other factor is where the power is applied on your sail boat. Your sail(s) have one point that is the centre of that power. Depending on sail trim, heel, wind strength, sea state etc… this point can move around a bit which is why few boats will keep a course without helm input but overall it won't shift too far. That is your “Centre of Effort” or CE.

When your CE lines up vertically with your CLR, your helm is neutral. (Figure “A”)No input required if you are on course. If the CE gets forward of the CLR the boat falls off, Lee helm. If the CE is aft of the CLR,(Figure “B”) there is your weather helm as the power in the rig is now putting more effort aft, it pushes that part of the boat away from the wind which causes the bow to turn into the wind as she pivots on the CLR. This must then be corrected by rudder which when used to excess is nothing but a big brake.

 What to do? You can't easily change your boats hull/rudder design but you can alter your CE without cost and the article you have just read explains how. Chronic weather helm can often be cured or at least helped by rig adjustment. Moving the mast head forward brings the CE forward. This will reduce weather helm. Conversely, moving the mast head aft, or putting in “rake” has the opposite effect. If the weather helm can't be cured to satisfaction by rig adjustment then it's time to talk to your sail maker. I was at the helm of a 100 foot schooner, The South Passage, and noted the heavy helm. The skipper told me it used to be even worse. The ship had had to have the main boom shortened and sail area reduced to make the ship manageable. Sure enough, when I looked at older photo's you could plainly see the change. They didn't take off just inches!

If you can adjust your forestay anchoring point or mast step forward, these are also methods to move your CE forward to mitigate weather helm.

If your boat has weather or lee helm, or if your boat points better on one tack than the other, the information in this and Petrea’s article should help you work it out.

But! (There is always a but!) Don't mess around with this if you aren't comfortable with your understanding of the information. Do take baby steps in your learning curve if you can. Easy conditions near a place where you can source pro help for example but do not fear your boat either. Your pro can't usually take an all day sail to “fine tune”. Sailors have been doing this for thousands of years; chances are we aren't any dumber than they were.

My qualification? None really, and that’s my point.
I was able to listen to people of Petrea’s qualification and apply the information successfully. I am proof that any simple sailor can do it. Also thanks to Dana Freeman.