At different speeds, your boat needs to be trimmed in different ways, both to get the maximum speed out of your boat and also the most comfortable ride.
You can trim your boat in two ways; fore and aft – raising and lowering the bow, and from side to side levelling the boat if it is leaning to one side. Don’t forget that where you position people and kit in the boat will also affect the trim of the boat.
Leg in to start to keep the prop in the water and help the boat get on the plane.
On the plane ease the leg out to achieve the best speed. Ease out too much and the prop sucks in air from the surface, making it spin faster but lose grip on the water, therefore slowing the boat. Ease the leg out by the correct amount and the revs increase slightly without the throttle being adjusted, therefore speed increases.
If the boat starts to porpoise (the bow bounces up and down), trim the leg in to regain control, and then slowly ease out to re-trim.
Trim needs constant adjustment. If crew move around the boat or there is a change in sea conditions or speed, you need to check the trim. Fuel use makes the boat lighter – you may need to trim differently when tanks are full or half empty.
Even when trim gauges are fitted, they can be unreliable. Practise in various conditions to get the best trim. When there are no gauges, use time increments to know whether the leg is up, down or centred. While in port count how long the tabs take to rise, lower and centre. When trimmed correctly the revs rise slightly and the helm feels lighter without pull to either side.