How to Read a Compass Underwater

Scuba divers often use a compass to navigate underwater. Scuba diving is a fun recreational activity that can be made even more exciting with the addition of navigating underwater trails. Most divers do not learn how to use more than the basics on a compass when they first start out because it isn't necessary. If you are wanting to become more advanced, however, it might be a good idea to learn a few more things about using a compass under water.

Instructions

    • 1

      Learn the basics of the compass before diving with it under water. The compass features a floating card with compass points and a degrees scale, a needle that points to magnetic north, a lubber line -- a line across the compass body that you align toward the direction of travel -- and a rotating ring around the edge of the compass called a bezel, which contains needle index marks. You move the bezel to mark the direction the needle is pointing when you take a reading. The compass must be held directly in front of the eyes and kept level so the north seeking needle can move. While it looks like the card and needle are moving, they remain stationary while the compass case spins around them.

    • 2

      Practice using a compass in clear water before taking it on an underwater trail or excavation that will not be clear. This gives you a better idea of how to use it in those conditions.

    • 3

      Swim in a triangle formation and watch how your compass reacts. Swim in other safe areas with multiple turns to learn how to use your compass.

    • 4

      Take bearings on objects or places by facing in the direction of them and noting the placement of the bearing in the viewing window of the compass. This helps ensure that you do not get lost while under water.

    • 5

      Hold the compass central and parallel to your body, not at an angle, while swimming to get to a bearing accurately. The compass must be absolutely horizontal and directly in front of you.