User Guide > Dynamics and Effects > Fluid Effects > Fluid Effects Menus > Fluid Effects > Fluid Effects > Ocean >
Fluid Effects > Ocean
> Add Boat Locator
Boat locators follow the motion of the ocean in the Y direction, but additionally rotate in X and Z to allow the boat to pitch and roll in the waves.
Fluid Effects > Ocean
> Add Boat Locator > 
If you want to move the position of the locator interactively, the locator cannot be connected directly to the expression. In this case, turn on Free Transform.