In the first installment we covered the various parts of the compass and how to take a bearing and how to convert that into a reciprocal course. You can find that discussion Here in the thread entitled Compass Basics... the Lubber Line If you haven't read that thread, it really lays down the basics for this thread. I promise there is a link BACK to this thread when you are done!
Orienteering on land is simple. All you need to do is to calculate your stride and learn to set and follow a compass without having to deal with a good deal of other distractions and stressors that come from being in a hostile environment. It is my suggestion that you practice on land first with the compass you will be using underwater so that using it starts to become second nature. These are the procedures I use for my AOW students. You will also need three or four markers and an underwater slate.
OK, first let's find an open field. The bigger the better. Walk a few feet onto the field and drop a marker. Now pick a point... make it any point that you can see. Point your lubber line directly at this point and move your bezel so that the needle is over the north marker (like we did in the first installment). If we were trying to run this like a land based orienteering course, I would give you the direction I wanted you to travel, but that's not what I want to do here.
The Triangle:
All set? Lets try walking twenty paces while looking at the COMPASS and not at your reference point. Again, please do this in a place where you are safe to walk without having to negotiate traffic, discarded ordnance or the like. After you have finished your walk, check your reference point again. Are you still on target? Does it have a different reading now? It should, but it's not unusual for people to have a drift to their walk and so have a different reading when they finish. It won't be a HUGE variation, but it's possible. Drop another marker. Now, since we are doing a triangle, lets divide 360 by three and add that to our initial setting. If your sum is lower than 360 just go with it. If it is OVER 360, then subtract 360 from it to get your next heading. So, that 270 heading plus 120 degrees becomes 390. Subtract the 360 and we now have our new heading to be 30 degrees! Move your bezel, line up your needle with the north symbol and take another 20 paces on your new heading. Drop a marker. Add another 120, and take another 20 paces on your latest setting. You SHOULD be standing on your initial golf ball. No? Did you have a drift when you did the first leg? Well, practice makes perfect. Choose another point and redo the exercise until you feel confident.
The square:
It's the same as above, but since there are 4 turns we will divide 360 by four and add one more leg to our journey. We can keep doing this for any equilateral polyhedron.
The rectangle:
The only wrinkle here is that leg 1's distance must equal leg 3 and leg 2's distance must equal leg 4.
Underwater:
If you have stuck with me up until now, you should have a good feeling for the compass and how to set it. Hopefully, you have good buoyancy and trim for the next part. For this exercise you should have your compass, three marker buoys (Walmart in the boating and/or fishing department) and your slate. If you are in navigable waters, be SURE to use a diver down flag. You and your buddy can take turns toting it as the other person works on their navigation. On land we can quantify our paces and come up with a reasonable way of measuring our progress. Underwater we are going to use kick cycles or time. Of the two, I prefer time but either way can be used. For your initial foray, you should try to find a lake with a bare minimum of current in it, but low vis is fine. Now, act like you are back on that field and go through your exercises. EXCEPT this time drop a marker buoy as your marker (make sure it deploys to the surface). Hopefully this lake is in 30+ foot of water and that you can stay at 20 for the exercise. I want you to maintain your chosen depth throughout.
At Hudson Grotto, I don't have my students drop markers. We are in 80+ feet of water and they do this at approximately 30 feet. However it is DARK and they have to rely on that compass to navigate.
Please repeat this exercise until you have it down. Take your time and swap off with your buddy and compare how well you do.
That's it in a nutshell. Of course, whenever you dive from shore or a boat you should be using the reciprocal method discussed in the first installment. Well this has gone on for a bit longer than I had anticipated, so look for installment #3 which will cover drifts, interruptions, way points and of course using your terrain to aid in your navigation.
Orienteering on land is simple. All you need to do is to calculate your stride and learn to set and follow a compass without having to deal with a good deal of other distractions and stressors that come from being in a hostile environment. It is my suggestion that you practice on land first with the compass you will be using underwater so that using it starts to become second nature. These are the procedures I use for my AOW students. You will also need three or four markers and an underwater slate.
OK, first let's find an open field. The bigger the better. Walk a few feet onto the field and drop a marker. Now pick a point... make it any point that you can see. Point your lubber line directly at this point and move your bezel so that the needle is over the north marker (like we did in the first installment). If we were trying to run this like a land based orienteering course, I would give you the direction I wanted you to travel, but that's not what I want to do here.
The Triangle:
All set? Lets try walking twenty paces while looking at the COMPASS and not at your reference point. Again, please do this in a place where you are safe to walk without having to negotiate traffic, discarded ordnance or the like. After you have finished your walk, check your reference point again. Are you still on target? Does it have a different reading now? It should, but it's not unusual for people to have a drift to their walk and so have a different reading when they finish. It won't be a HUGE variation, but it's possible. Drop another marker. Now, since we are doing a triangle, lets divide 360 by three and add that to our initial setting. If your sum is lower than 360 just go with it. If it is OVER 360, then subtract 360 from it to get your next heading. So, that 270 heading plus 120 degrees becomes 390. Subtract the 360 and we now have our new heading to be 30 degrees! Move your bezel, line up your needle with the north symbol and take another 20 paces on your new heading. Drop a marker. Add another 120, and take another 20 paces on your latest setting. You SHOULD be standing on your initial golf ball. No? Did you have a drift when you did the first leg? Well, practice makes perfect. Choose another point and redo the exercise until you feel confident.
The square:
It's the same as above, but since there are 4 turns we will divide 360 by four and add one more leg to our journey. We can keep doing this for any equilateral polyhedron.
The rectangle:
The only wrinkle here is that leg 1's distance must equal leg 3 and leg 2's distance must equal leg 4.
Underwater:
If you have stuck with me up until now, you should have a good feeling for the compass and how to set it. Hopefully, you have good buoyancy and trim for the next part. For this exercise you should have your compass, three marker buoys (Walmart in the boating and/or fishing department) and your slate. If you are in navigable waters, be SURE to use a diver down flag. You and your buddy can take turns toting it as the other person works on their navigation. On land we can quantify our paces and come up with a reasonable way of measuring our progress. Underwater we are going to use kick cycles or time. Of the two, I prefer time but either way can be used. For your initial foray, you should try to find a lake with a bare minimum of current in it, but low vis is fine. Now, act like you are back on that field and go through your exercises. EXCEPT this time drop a marker buoy as your marker (make sure it deploys to the surface). Hopefully this lake is in 30+ foot of water and that you can stay at 20 for the exercise. I want you to maintain your chosen depth throughout.
At Hudson Grotto, I don't have my students drop markers. We are in 80+ feet of water and they do this at approximately 30 feet. However it is DARK and they have to rely on that compass to navigate.
Please repeat this exercise until you have it down. Take your time and swap off with your buddy and compare how well you do.
That's it in a nutshell. Of course, whenever you dive from shore or a boat you should be using the reciprocal method discussed in the first installment. Well this has gone on for a bit longer than I had anticipated, so look for installment #3 which will cover drifts, interruptions, way points and of course using your terrain to aid in your navigation.
