Article by Capt. Steve Katz
Pitch and Roll
Heading out on the water for boating or fishing should be a comfortable and safe experience, no matter the size of your boat.
While a lot of factors, including the weather, contribute to the ride of the boat, controlling the pitch and roll of the vessel can make a big difference for the comfort of the guests and crew.
Almost all planning boats are equipped with some type of ride control system, which is commonly referred to as trim tabs. Trim tabs are small adjustable control surfaces, connected to the trailing edge of the boat’s hull to counteract forces on the boat allowing adjustments to the ride of the boat.
Speed, weight, weather, and sea conditions can affect how your boat travels through the water on any given trip. Often the pitch of the boat, the up and down angle of the bow (and stern) of a boat is drastically affected by weight and speed. Generally, boats are designed to ride close to level with the water line, which allows most of the length of the hull to be in the water and provide a smoother ride for all onboard. Additionally, a level boat has better visibility from the helm, which helps with the safe operation of the boat. When the bow of the boat is too high, less hull is in the water and often the bow is too far out of water to be able to cut through the waves as designed, resulting in waves hitting the boat midship, causing a rougher ride.
Speed, weight, weather, and sea conditions can also affect the ability of the boat to ride level from side to side, which is referred to as roll. Often excessive roll angle is caused by uneven weight distribution, usually by the passengers but often excessive roll angle can be caused by the wind pushing on the bow, lifting, or lowering one side of the boat.
Fortunately, trim tabs can adjust the pitch and roll of the vessel at the same time. These small control surfaces, typically two, one on each side of the stern of the boat are adjusted independently to allow the captain to make small adjustments in each trim tab that results in big adjustments in the pitch and roll of the entire boat. The movement of a trim tab is controlled by an electric or hydraulic system operated from the helm to lower each trim tab independently to adjust the ride. Trim tabs lift the transom and lower the bow by pressing down at an angle into the water flowing under the boat. The sharper the angle, the greater the effect of the trim tab. Some trim tabs stick out past the stern of the boat and provide similar action to the flush mounted units under the hull. Trim tabs do not need to be lowered into the water very much, less than a few inches to make a dramatic effect on the boats ride.
It was the well-known Bennett company who originally invented trim tabs in 1959 to increase efficiency, performance, and safety of boats. These were and still today, a flat control surface that is attached to the boat on the leading side with a hinge or pivot point and a ram of some type on trailing edge attached to the boat to lower and raise the tab into the water stream below the boats surface.
There are now a few offerings of “trim tabs” that work in a different fashion and achieve same or better results than the conventional flat trim tab. Interceptors style ride control systems are mounted on the lowest surface of the transom, and like trim tabs, interceptors redirect the water flow to change the attitude of transom and bow. Where they differ is that interceptors enter the water flow at approximately a right angle, or vertically. Also, interceptors extend only a small distance downward to achieve noticeable results. Popular brands are the Humphree and Zip Wake, though not unique to interceptor style systems, they often include an automated control option, where the trim system can constantly adjust to different conditions to provide the desired pre-programmed boat running attitude. These systems operate with electrical motors that extend and retract the interceptor into the water.
The newest style of interceptor is offered by Seakeeper, called “Ride”, and not surprisingly incorporates a unique deployment mechanism and electronic control system that can make up to 100 adjustments every second to maintain the pre-configured pitch and roll of the boat. No more of the bow pointing to the sky while getting on a plane, the system keeps the boat level during the holeshot and improves the time to plane. When people are moving around the boat, the Seakeeper ride senses the change to the roll angle and quickly levels the boat as fast as the people are moving around.
No matter the size of your boat, a ride control system is important to keep the pitch and roll under control and enjoy your time on the water.§
