It's pretty natural that if you are watching a boat go by, you turn your head to follow it. The camera is no different. The Track to Constraint command lets you do just that. The following steps will help you to track the boat:
Select the camera with the RMB.
Press the Shift key and the RMB to select the boat.
Press Ctrl + T to get the tracking menu. Select Track to Constraint.
Press the NumPad 0 key to get the camera's view.
Press Alt + A to preview the animation. Press Esc when you are done watching it.
Save the file with a unique name.
Tracking is very similar to parenting. Select the camera and then select what you want to track. Press Ctrl + T and select Track to Constraint, and the camera will follow the object you want to track.