Suppose you are expecting to have good visibility at a Texas lake, but when you arrive the visibility has decreased. Maybe it rained, or a lot of swimmers stirred up the lake's bottom. You still want to dive, so what do you do?
I recommend that you practice your underwater navigation skills. A cloudy lake should not stop you from diving, as long as you still feel safe. Don't dive if there is no visibility or the water is very dark.
Lake Navigation with a Compass
To navigate underwater, you need to have a compass and a final destination. Here are the steps to take to reach your destination, even with low water visibility.
- Before you descend, locate the direction of your final destination. Most man-made items put underwater as an attraction have a buoy to indicate their location, so you can use the buoy as your destination. Also note the distance to your destination.
- Facing the final destination, align your compass to that direction. (See Figure 1 below.) Note and remember the degree that the compass needle points to. If your compass can rotate (called the Turntable Housing in Figure 2 below) then use the turntable to mark the degree of the needle.
- Now descend using proper scuba rules. It is okay to rotate your body during descent.
- Once at a comfortable depth, look at your compass while the compass is aligned with your body, the same way as in step #2.
- Align the compass needle to the degree found in step #2, by rotating your body with your compass, not just by rotating your compass alone.
- Swim in the direction that keeps the needle steady on the degrees needed. Swim in a straight line, and check that the compass is still on track every minute or so. If you see that you are no longer swimming in the correct direction, change your course.
- Pay attention to the distance you have swam. If you had gotten off course at all in step #6, be careful to not swim too far and pass your target. If you think you've gone to far, return to the surface of the lake and make a new heading (start over at step #1).
- You will eventually reach your destination, such as a sunken airplane or whatever you chose to dive to.
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| Figure 1: Align Compass with your Sight (Source: IDC1) |
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| Figure 2: Compass (Source: ABC of Hiking2) |
Clear Lake for Practice
Remember too that navigating using a compass takes practice! Use the steps above to practice in a clear lake, so you can use your long-distance sight as a backup during your dive. A very clear lake to practice navigation in is at Athens Scuba Park, as shown below.
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| Source: Athens3 |
So remember, wherever you dive in Texas, don't get disappointed if low visibility sneaks up on you! Your dive will turn into a great opportunity to practice your navigation, and you can still make your dive fun once you reach your destination.
Footnotes
[1] PADI Specialties. (2010). IDC Thailand. Retrieved March 24, 2011, from http://www.idcthailand.net/nl/specialty-cursussen
[2] Compass Navigation & Using a Compass. (n.d.). Retrieved March 24, 2011, from http://www.abc-of-hiking.com/navigation-skills/compass-navigation.asp
[3] Athens Scuba Park. (n.d.). Retrieved March 24, 2011, from http://www.athensscubapark.com/default.asp
