301 is the relative bearing. In other words, relative to your sub, with 000 being on your bow, no matter which direction you are heading, and, as Captain said above, 301 being 59 degrees to your left.
True bearing would be the actual compass course that you would have to steer to put your bow directly on the target.
Example: If you were on course 270 and the ship was reported bearing 301, you would need to come to course 211(270-59=211) to put the target directly in front of you.
Hope that made sense.
