You can make an object float by adding a dynamic locator to it. Dynamic locators follow the motion of the ocean along the Y-axis and they react to dynamic attributes such as buoyancy, gravity, and damping.

To make objects float

1. Select the objects you want to float, and if the scene has more than one ocean, select the ocean you want the object(s) to float in.
2. Select Fluid Effects > Ocean > Float Selected Objects > .

   The Float Selected Objects window appears.

   By default, locators are connected directly to the expression, enabling you to rename locators without breaking the expression.

   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.

3. Click Float Selected Objects. Maya connects the object to a dynamic locator to it.
4. In the Extra Attributes section of the locatorShape Attribute Editor, modify the options to simulate dynamic effects (see Dynamic locator). These serve as inputs to the expression.
5. Play the animation using the playback controls at the bottom of the Maya window.