A few dive trips ago I was diving in Curacao.  I was with a group of 10 divers and a divemaster.  We starter at the tug and worked our way out from there.  I was the first to reach 1500 PSI which was the turnaround point.  The divemaster gave the turn around signal and I started back with my buddy a couple of feet behind me.  I turned around to check on him and found my buddy and the rest of the group gone!  Now what?  I check around and found them nowhere to be seen, so I started to reverse my trip, alone.  Being all-alone in the vastness of the ocean with over 6000 feet below me is an unsetteling feeling.  I used some of the markers I had seen and made my way back to the tug and then after a safety stop on to the boat.  I latter learned the divemaster lead the group back another way through a coral head.  Without some navigation skills I would have probably gotten lost.  This is why I think it is extremely important to know how to use a compass correctly.

Using a Compass:
Unfortunately using a compass underwater isn’t quite as simple as on land.  Because we are swimming it is possible to have the compass aligned on the correct bearing, but swim in another direction.  To prevent this the compass must be centered on your body, and pointed in the same direction as you are swimming.  To ensure this is the case you can:

Wrist mounted compass.  Stick your arm without the compass on it straight out in front of you.  Grasp the elbow of that arm with the compass arm.  Your arm with the compass on it should now be bent at a right angle with the compass directly in front of you.  By swimming like this you ensure that the compass is centered on your body and pointing in the same direction you are swimming

Slate mounted compass:  Hold the slate with both hands in front of you.  Keep both of your elbows bent at about 45 degrees and the slate level.  This should keep the slate aligned with your body.

Consol mounted compass.  This is the hardest compass to align properly.  Make sure the hose is long enough for your consol to be easily moved in front of your face.  Using both arms hold the compass in front of you, making sure each arm is bent equally.  It is easiest to keep your arms held properly if you tuck them against your body.  Concentrate on keeping the consol in line with your body - if the consol is angled you’ll swim in the wrong direction!

Following a Bearing:
The main purpose for a compass when diving is to allow you to follow a bearing while you swim.  Direct-reading compasses excel in this, whereas it can be quite difficult with an indirect-reading compass.  Both methods are described below.

Direct Reading:  At the base of your compass should be a small window.  When you look through the window only a small portion of the magnetic disk should be visible.  To follow a bearing simply hold the compass properly in front of you and rotate until you see your desired bearing in the window - you are now facing the direction you want to swim!  For example, if you wanted to swim at a bearing of 60 degrees you would turn until you see “60″ in the window.

Indirect Reading:  Following a bearing is a little more difficult on an indirect reading compass.  Around the compass should be a rotating bezel.  On the bezel should be bearings (in degrees) and alignment markings.  At the top of the compass should be a mark, which does not rotate when you turn the bezel (termed the set mark), and in the compass there will be a floating magnetized needle.  The following steps will describe how to use the compass to set a bearing.

Rotate the bezel until your desired bearing lines up with the set mark (i.e. if you want to swim a 60 degree course, rotate the bezel until “60″ is at the top, immediately below the set mark).

Holding the compass level and in front of you rotate until the magnetic needle is in-line with the alignment markings (the needle will be pointing to the ‘0′ or ‘N’ on the bezel if you’ve aligned things right).

You are now facing in the direction you want to swim.

Holding the compass level and in front of you rotate until the magnetic needle is in-line with the alignment markings (the needle will be pointing to the ‘0′ or ‘N’ on the bezel if you’ve aligned things right).

You are now facing in the direction you want to swim.

Take a navigation course, use your compass and have safety equipment such as a safety sausage, air horn, mirror or whistle with you in case you should get lost.