Yachting Art Magazine

Expert Tips - All about trimmer systems, so needed, yet so little used…

The trimmer system on a boat is a trim leveler installed on motor boats equipped with outboard engines or a Z-drive propulsion. It allows to change the trim of the boat, and thus increase or reduces the wet surface on the hull. You gain in performance or comfort adjusting to the speed and the state of the sea.

Expert Tips - All about trimmer systems, so needed, yet so little used…

The trimmer system is essential for boats equipped with outboard engines (starting from 25cv), but also with Z-Drive propulsion. In reality, too few recreational boaters use it, losing out in comfort and performance, but also affecting the consumption of their boat.

The trimmer system? what is it?

Technically, the trimmer system is a large hydraulic cylinder located on the
attachment of an outboard motor or to the outlet of the base of a Z-Drive propulsion allowing the propeller to be moved apart or brought closer to the transom of the boat.

The trimmer system is controlled by a switch located on the throttle. In pushing the "Up" position, the engine is moved apart from the transom (thruster rises); By pressing the "down" position, the engine is brought closer to the transom (thruster falls).

The trimmer system, for what?

Using the trimmer de facto changes the angle of thrust of the propeller and thus adjusts the longitudinal attitude of the boat in motion. The trimmer system
is used in the different phases of navigation: lift-off, cruising speed, etc. It allows for the boat to increase performance, be more fuel-efficient, but also improves comfort, depending on the state of the sea.

Trimmer system by calm sea

At start-up, trimming in negative (bring the base of the transom closer together), will help planning while increasing the lift benefiting from the qualities of the hull. Once in navigation, tripping in positive raises the bow, thereby reducing the wetted area to one third of the rear hull and promoting speed.

In calm seas, the desire to gain speed can encourage the yachtsman to trim to the maximum, to the limit of the ventilation of the propeller! It is a temptation that must be curbed, mainly because the effect of ventilation of the propeller loses in speed, but also and foremost, because according to its hull, the boat will soon tend to hoarse (tangling) at the slightest chop encountered, and in particular at the wakes of other ships...

Caution, a positive trim adjustment results in a ventilation effect of the turn-helix. It is therefore advisable to return to neutral trim setting when negotiating a tight turn.

In a calm sea, a good trim setting is characterized by a lighter steering (except with hydraulic steering!), a neutral bar (boat that does not pull to port or starboard), and a very stable vessel that found a good balance between speed and stability.

Trimmer system by heavy sea

The trimmer system is particularly useful in heavy sea navigation conditions.

By tail sea and wind, the boat tends to plunge into the wave. To trim in positive (rising the bow), relieves the bow and raises the nose of the boat.

By head sea and wind, the bow tends to rise and the boat is being banged at the back of the hull. It is therefore necessary to trim in negative (lowering the nose of the boat), to allow the front of the hull, i.e. the V of the hull to work and mitigate the fall of the boat.

Using the trimmer system requires real attention

Using the trimmer system of your boat requires real attention and a true learning from the boater, a bit like the skipper of a sailboat that monitors and refines its sail in permanence.

This reality may explain why a large number of owners of motor boats use it little, or badly, as specified by Yann Le Fillastre, responsible for parts and accessories at Mercury Marine France: "Today, we see that the majority of boaters use little or poorly the trimmer system of their motorboat, with the direct consequence of a sharp increase in consumption, especially before lift-off. This misunderstanding comes mainly from the fact that they are generally not trained to do so. Trimming in itself is not complicated, but requires attention, depending on the pace and the fact that you are trying to maintain your boat at the air limit".

=> Conseils d'Experts - tout sur le Trim, si nécessaire, et pourtant si peu utilisé

Expert Tips - All about trimmer systems, so needed, yet so little used…

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