How to Navigate Underwater

Because you can't tell east from west by looking at the sun when you're underwater, here's how to navigate using natural markers or a compass.

Instructions

Difficulty: Moderate

Things You’ll Need:

• Scuba Guide Books
• Newspaper (for Tide Tables)
• Dive Compasses
• Dive Computers

Natural Navigation

1. Check tide tables before starting a shore dive.
2. Note your surroundings. Check for landmarks - an island, rock outcropping or sand trap - to orient yourself during and after your dive.
3. Start your dive by moving into the current so that you can glide back in with the current at the end of the dive when you're tired.
4. Look for bottom features to help orient yourself during the dive.
5. Keep in mind that ripples on a sandy bottom run parallel to the shoreline.
6. Remember that the depth usually increases away from shoreline. Check your depth gauge frequently.

Compass Navigation

7. Wear a dive compass on your right wrist as you would a watch.
8. Understand that a dive compass indicates direction with a dial divided into 360 degree marks and a magnetic needle that always points north.
9. Hold your arm with the compass at right angle in front of you, where you can see the face.
10. Stretch your left arm out in front of you, and grab it at the elbow with your compass hand. This position will keep the compass steady, level and visible.
11. Align the needle with the direction you wish to travel if you're using a dive compass marked in the counterclockwise fashion, which most are.
12. Keep in mind, north is at 0 degrees, east is at 90 degrees, south is at 180 degrees and west is at 270 degrees. To travel south, turn in the water until the needle points at the 180-degree mark.
13. Look for an object in the direction you wish to travel and swim toward it while glancing at the compass periodically.

Tips & Warnings

• Many scuba guide books have maps or aerial photographs of dive sites to assist with navigation.
• On a traditional hiking compass, the degree markings increase from 0 to 360 clockwise around the face. Most dive compasses are marked from 0 to 360 in a counterclockwise direction. This is because the compass is fixed to your wrist, and not held in your hand where it can be easily rotated.
• With the compass on your right arm, the north mark is aligned with the strap on the outer side of your wrist. This mark is fixed, but the compass may have a set of course brackets marked on a rotating face.
• Analog dive compasses must be held level, or the needle will drag and cause inaccuracies.
• Avoid diving at a site with strong currents. Check with local dive shops or guides for hazards.
• Scuba diving is an inherently dangerous activity that can result in serious injury or death. We recommend that you seek proper training and equipment before attempting this activity.