Chine walking is most prominent in high performance V-hull boats. So, what is chine walking? Chine walking is the rapid side-to-side and often uncontrolled movement of the hull. In some cases, chine walking can become more severe by itself and this is called increased fluctuating instability. Let’s delve deeper into the factors that cause chine walking and find ways to reduce this dangerous occurrence. Some boats can even chine walk during a turn and this can be really disconcerting, even for an experienced skipper.
Chine walking can be caused by a number of things such as hull and design inconsistencies, incorrect hull setup, wind conditions, water conditions and even skipper inexperience. What happens is that as the V-hull accelerates, the lift increases and reduces the amount of the hull that is in contact with the water surface. The hull is now essentially balancing on a small part of the V-hull and this is when it becomes increasingly difficult to balance the equilibrium of the boat. What occurs next is that the hull begins to roll from side to side between the starboard and port chine. This rocking motion can get more extreme with each motion and the driver needs to balance things out with adjustments to steering, trim and throttle in order to restore the boat to its natural balance and stability.
Is it possible to accelerate through the chine walking? The answer is simply that it is dangerous and should not be attempted. Drivers often feel that they can trim the boat sufficiently and power through the chine walking and the boat will stabilise itself. With practice, it is possible to stabilise the boat with trim-, throttle and steering adjustments, but first prize is always changing the hull setup to stop the problem in its tracks.
Chine walking is usually observed more often in V-hulls with high-lift running pads or narrow running pads, high deadrise hulls and straight V-hulls with no pad. All of these hull designs are naturally harder to balance at high speed. V pad hulls all have a tendency to fall off the pad under some conditions. This is normal for these types of hulls and can often lead to chime walking. A planing pad or beam that is too narrow will also often increase the instance of chine walking at high speed.
MINIMISE CHINE WALKING:
1. Check and adjust the boat’s steering. There should be no play. Remove slack from cable systems. Good control always improves boat stability. Hydraulic systems should be bled to remove any air bubbles and the increased play in the steering system.
2. Change rubber engine mounts for solid mounts to reduce play between the steering and the motors. Rigid mounts offer better boat control and more precise steering at higher speeds.
3. The flatter the running surface under the hull, the better the boat handles, particularly in speed boats and highperformance boats. If the balance is out in the boat, this can contribute to chine walking. Always try to ensure that the boat is well balanced.
4. Adjusting engine height on a boat can make a big difference when trying to reduce chine walking. First ensure that the motor is centred and straight. Test the boat at different speeds by having the motor at different heights. Often when the engine is raised on the transom it will reduce drag on the lower unit and improve handling instability such as chine walking.
5. The correct propeller design can change the balance of a hull. Diameter, pitch, rake and blade number can all influence how the boat performs. Propeller testing can be time-consuming, but it can really be of benefit to high-performance boats, adding to stability and reducing instances of chine walking.
6. Minimise the trim angle and use as little positive trim as possible to reduce chine walking. More trim with an increase in the running angle of attack can cause an increase in instability. If chine walking begins to present itself, you’ll need to reduce trim slightly. If you are the skipper of a boat that has enough power to experience chine walking, then safety should be foremost on your mind and the boat should be equipped with the necessary life jackets, helmets, kill switches and anything else that can minimise the risk to the occupants.
