Underwater navigation

[AfterDark]

After reading the whole thread the OP got some great advice and ideas. I'll add to the kick counting method pace beads. I use them on land and underwater.
Pace beads are a string made into a loop with 2 sets beads on it separated by a knot and a knot on one end. On one set of 9 beads count a set of kicks the number is up to you, say 10 for each bead, so every 10 kicks pull 1 of the 9 beads down, count 10 more kicks repeat with another bead….. The second set of beads consists of 4 larger diameter beads each bead is the tenth bead of your set of 100 kicks and marks 100 kicks. After pulling the 9^th bead down pull a larger bead down completing one cycle of 100 kicks. After using all the beads record total kicks on your slate slide them back up and continue. This method makes remembering kicks easier and errors smaller.

Pace Bead credit to the US Army Rangers. Underwater adaptation AfterDark



I use an old Scubapro LS1 compass mounted on my console, never a problem as someone posted operator error not an equipment issue.
All the visual, depth advice is a big part of getting back to where you started, also you can incorporate tide change times and the direction of the current into your dive plan. Time can be judged by tidal changes and the current will also have an effect on your tracking and direction, better to work with these forces than against them.... practice.. practice..practice.

 

[DivemasterDennis]

I think this is a great thread with lots of good navigation tips. Navigation is second only to buoyancy control on my list of important skills to master in order to be a competent diver. (there are of course more skills on the list)
Here is my short list of important navigation tips:
1. Believe the compass.
2. Navigation involves vectors which have both direction and distance.
3. When diving on you own in conditions that require good navigation, a slate is an essential tool. Use it to note your course. Some people who do navigation skills work regularly can maintain a good mental chart, but a slate is a must for most of us.
4. Distance determination is harder to master than direction determination. All the suggested methods are useful: kick cycles, time, air consumption. Unfortunately, none are constant. Use the method that is most constant for you, which will vary with the conditions you are diving. Each of them requires lots of practice to be mastered.
5. However your compass is mounted, (and I'm ok with console mounts or compass only on a retractor) holding you compass level is important.
6. Make use of landmarks to confirm your location.
7. Always be thinking about how to make your navigation more precise.
I like to navigate from object to object when possible. Example: we went off shore at 80 degrees for 5 minutes to the big coral head (note on slate) The we went more or less 145 degrees to the main reef, taking 3 minutes, where the big elkhorn coral was (note on slate).Then we went on a course more or less 180 degrees for about 10 minutes, looking at the reef. Now I could try to navigate straight back to our point of origin (about 330 degrees for 14 minutes) OR... I can reverse my direction by going on three simple reciprocals, using the landmarks for confirmation. The second way is easier.
If you to be a good and accurate navigator, practice with your compass on every dive, even if you are being led by a divemaster. It's a little work, but it's actually nice knowing where you are and how to get home!
DivemasterDennis

 

[Nwcid]

Great stuff guys and this seems to have stimulated some good conversation.

So far kinda of what I am getting is I am expecting too much accuracy (must be a carry over from land but that is when used in conjunction with a map). On the other hand on land with good vis you look and say "I want to go over there" and can still reasonably easy find your way back to the area you started from. Now that I am doing more snowboarding it is very easy to get disoriented doing land nav with limited vis in heavy fog. You start hopping from known point to known point vs seeing where you want to go and heading that way.

Since we will not have maps of the area we dive for the most part (I did find some contour maps of a couple of the small lakes we want to dive) sounds like the first time or two in the area will have to do the best we can and so some surface checking.

I am not expecting pin point accuracy but was trying to just do some general swimming in an area and not having to pop up a lot to see where we are. For the diving we are doing now I am not looking to come back up exactly where we started but at least in a close general area.

 

[DiveNav]

Being able to build a "mental image" of a dive site could really help with underwater navigation.

Exploring a virtual map with our eDiving simulator is one way to help build such image.

I still remember a thank you note from a diver that went on a dive trip on the USS Spiegel Grove after eDiving it; "it was like a deja vu" he wrote.

And now that we are working to link eDiving with divePAL, soon not only you will be able to virtually explore a dive site, but you will also be able to review - and log for future use - where you actually went.

Alberto (aka eDiver)