Underwater Navigation - Beyond the Compass

Wall diving, whether at your local limestone quarry or on a reef wall, is likely the easiest way to get started and gain confidence. It is best if you start before you enter the water. Take out your compass and see which direction the shore line runs. It is always to get a sense of direction above water first.

At a quarry you can descend along the wall to a comfortable depth let's say 40 feet. As you descend pay attention to any landmarks that are at twenty feet not the depth you will start the dive but the depth you will return. At Haigh Quarry, for example, if you start off the south dock there is a pipe that comes out of the wall about 25 feet and descends at a 45 degree angle into the quarry.

Swim at forty feet keeping the wall on one side either right or left. When you or your buddy reach one half tank ascend to half the original depth and return keeping the wall on you opposite side. Because you are shallower you should have plenty of air to return to your starting point. There are two ways to know when you are back at your starting point, either track you time and it should take you as long to get back as it did to get to the turn around. You can also look for the landmark you spotted on your descent.

If this is a reef dive make sure you start out against the current. Your time will not be as accurate because of the current so it is critical you look make sure you find a landmark.

If you are diving in a quarry and you took a compass reading before you started you will be able to get a general idea of where you are by the direction you are swimming. For example, at Haigh quarry if you started off south and your compass tells you are you are swimming east you know you have turned the corner and are along the east wall.

There are physical clues that can help you as well. In a lake the water gets shallower as you are getting closer to shore. There may also be ridges in the bottom caused by wave action that parallel the shore. Of course, if you took a compass reading before you entered the water you would be able to easily determine which direction the shore is.

If you are in the lake along a sloping bottom and stay at a constant depth you can be reasonably assured you are tracking the shore. Keep the shallower depth on one side and it works like a wall dive.

If you are diving along a finger reef - a reef that extends from the shore in strips - the fingers usually run perpendicular to the shore. You can count the fingers as you swim away from the boat. As you return you need simple count the fingers again to return to the boat.