Trim and Trim Tabs

Trim and trim tabs

Using engine trim and trim tabs correctly not only makes your day on the water safe and comfortable, but it will also increase your fuel burn. Trimming the engine works both on and off the plane, the off the plane is fairly simple, as when you come off the plane make sure you trim the engine back down and if fitted, trim tabs up. This not only makes sure your not pushing the stern of the boat in the water but when you throttle up again it makes you most efficient to get back on the plane.

What is engine trim?

All modern outboards and outdrives will have the option to trim, this will more than likely be through a hydraulic ram that is operated by a button on the side of the throttle control. All boats will trim slightly differently but the principles are the same for an outboard engines and inboard, out drive engines.

The trim of an engine will depend on the sea state and what direction you are travelling in, in relation to the wind and waves. I always instruct my students that trim is a constant.

Once on the plane, this is when we should trim, in a flat sea, trim up until the steering starts to feel lighter and the engine pitch changes slightly. If you over trim, it will sound like a helicopter is behind you as the prop comes out of the water and the bow of the boat starts to porpoise. Not enough trim and the wheel will still feel heavy and the spray from the chines will be well forward.

In tight corners trim down for more grip and no ventilation.

In a head sea we might trim down a little, this will help to stop hull lift and keep the bow down.

What are trim tabs?

Trim tabs are placed on the transom (back) of the boat, they help to keep the boat level in the water once on the plane. Trim tabs can be adjusted so that they will trim of the boat both fore and aft and left and right. I always advice my students trim on the engine or leg first before using the tabs.

For more information on engine trim and trim tabs please call 02381 242159.