Motorised planning boats can be trimmed to affect the way they behave in different sea and wind conditions. Two potentially different ways exist to achieve this; with stern drive units changing the angle of the drive leg or with stern trim tabs changing angle of either the port or starboard tab or both. With the stern drive units if the outdrive unit is brought in this causes the bow of the boat to drop which reduces slamming in a head sea. If the outdrive leg is angled out this causes the bow to lift which improves performance in a following sea. Similarly with trim tabs if both tabs are angled down this causes the bow to drop down and if angled up this causes the bow to lift. The advantage of trim tabs is that the port or starboard can be affected more or less by dropping or raising the tab on that side.
