The best way for a powerboater to cope with that situation is to learn more about how sailboats work and anticipate such movements. Sailboats operating with the wind behind them often must make similar abrupt course-changes–a movement that is called gybing. The principles are similar for both.

Q. Sometimes sailboats seem to be pointing in one direction, but moving on a different course. What causes this disparity?

A. Sailboats are propelled when the wind pushes against their sails, but sometimes there are other forces that help determine which way they're headed. If the wind is coming from abeam, for example, the boat is pushed sideways and ought to be moving at a 90-degree angle from its bow. But the effect of the wind is mitigated by the deep keel that extends below the sailboat's hull. The keel provides resistance against the force of the wind and transfers some of it into a forward motion for the boat. The result is that while the boat may be pointing in one direction, it actually moves at an oblique angle, much like a crab. That equation changes depending on the relative direction that the wind is coming from. Moral: don't judge a sailboat's course by its heading.

GLEN JUSTICEA powerboat's wake can pose a danger to a sailor on deck raising or taking in sail. It can knock them off balance, swing the boom or cause other problems that may result in an injury.Q. I often wave to sailboats as I zoom past, but my courtesy frequently is greeted by silence–and sometimes worse. Do I need to change my mouthwash?

A. Not yet. One of the major complaints sailors have about powerboaters is that they tend to roar by at high speeds, without regard to the impact–or damage–caused by their wakes. At a minimum, getting jostled by a large powerboat wake can spill the wind out of the sails, forcing the sailboater to spend several minutes building up enough speed to resume course–particularly in light winds.

At the worst, the jolt from a large powerboat wake can knock a crew member off his feet, causing injury. Sailors complain that powerboaters are too often oblivious to the impact of their wake; some don't even seem to get it when the sailor yells and points.

The most dangerous situation in this category comes when the sailboat is raising or taking down sail–which necessitates steering the boat directly into the wind–and a crew member is standing on the cabintop or in the pulpit, trying to gather and fold a sail. A large wake hitting a sailboat during such times means the crewmember must drop the sail and grab for the mast or pulpit, or risk being knocked down (or worse, overboard).

Of course, powerboaters also "wake" each other, so this concept should not be totally foreign. But the problem is greater on a boat under sail, which has more difficulty taking evasive maneuvers, such as turning into a wake to hit it head on and minimize roll. Being rolled by a powerboat wake also could cause the sailboat's boom to swing–and possibly injure or even kill a crewmember.

Remember: you, as a powerboater, are legally responsible for any damage or injury caused by your wake. You need to be aware of the impact your wake is having, whether you are near another boat, in a harbor or marina fairway, or around swimmers.

The best way to avert that problem–and the wrath of the sailboat crew–is to avoid steering close to sailboats at high speeds and to slow down when you see one of their crew members raising or taking down sail. And, learn–and follow–the rules of the road. If the sailboat crew isn't too stunned by your courtesy, you may get a wave–or even a smile–in return.

Even more fun, ask a sailor acquaintance to take you sailing some day and experience the frustrations and joys that sailors encounter first-hand. It may not change your life, but it could change your boating habits.