By: Bill Jennings
We have all experienced riding in a boat at idle speed and have it weave from side to side rather than following a straight line. Not only do other boaters give you the “learn how to drive” look, but your passengers tell you they are feeling sick. You will be glad to know, it’s not your fault. Furthermore, there is a procedure to correct this motion that we affectionately call 'hunting.'
The cause of hunting is interesting. Let’s start with a quick refresher on airplane wings. Air striking the leading edge of a wing splits into two parts, one part travelling over the top of the wing and the other along the bottom. The top of the wing has a slight hump built in, and this means that the air over the top must travel faster than the air along the bottom so that they join up together at the trailing edge. The faster moving air on the top creates a vacuum which in turn lifts the wing.
In a boat, water splits at the bow, (just as with a plane wing), and joins up again at the stern. At slow speeds, when your boat is set deep in the water and operating as a water displacing hull, the waterline runs the full length of the boat. Because of the curvature of the bow area, any steering input will slightly change the distance that water must travel down one side to meet the water from the other at the stern. Again, this speed difference creates a slight vacuum on one side of the boat. This small vacuum is sufficient to pull the boat off a straight course. Once the boat changes direction and the driver corrects, a pendulum effect or hunting begins. The secret to overcome this, is to avoid over correcting. Wait until the swing has reached its maximum in one direction, then add a slight wheel turn in that same direction. For example, when the boat swings to starboard - - just as it reaches its maximum swing and stops, add a small steering input, also to starboard. This process is something with which you will gradually become proficient.
If you wonder why some boats hunt more than others, the answer is simple: Not all manufacturers make the effort to design a hull that eliminates this phenomenon.