Navigation Question

[101recon]

Back in the day before GPS land navigation was accomplished by basically 2 things.An azimuth (compass direction) and a distance.I use my known pace count (the average number of paces I take per 100m) for reckoning distance traveled.While straight-line travel is often not possible due to having to go around obstacles,with practice one is still able to get pretty close to a desired destination.

I've read through a few of the nav threads and most seem to focus on the compass.The distance traveled seems to be the hard part to nail down.

Is anyone familiar with a method of "pace count" for diving? Perhaps a steady speed for a specific time.I've also seen kick-count mentioned.I'm thinking of timing myself between known distances to work out my average.Of course this wouldn't be exact but the land based version isn't either.Other than using a reel which must be recovered,how do you estimate distance traveled?

 

[Jim Lapenta]

You can use kick cycles, air pressure, and time. I normally use a combination of all of them. as a new diver kick cycles is the easiest for short runs. You can get more accurate by measuring the distance you travel during a cycle and using that pace. You must though be consistent and have very good control of your buoyancy and trim or accuracy will suffer.

 

[Diver0001]

Other than using a reel which must be recovered,how do you estimate distance traveled?

Jim sort of answered the question, but what you apply and how you apply it depends on how accurately you need to measure distance (and direction).

A good navigation specialty will provide you with a skill set and some ideas that you can apply for a variety of purposes in a variety of contexts.

For example, if you're looking for an object, you may swim a pattern with some accuracy over the bottom and perhaps count kick cycles but if you only want to be close the exit point after an hour of diving then you aren't going to count kick cycles for that.

It really depends on what you're doing.

R..

 

[gcbryan]

I haven't used kick cycle counting since I learned about it in AOW unless it was to search for something as mentioned above.

I think it's more about direction, time (taken current into consideration) and natural navigation (noting landmarks along the way).

It's really no different than navigating your way around your local mall.

 

[rstofer]

Well, other than the fact that you can see to the horizon in a mall and you don't suffer from the mask induced tunnel vision. The ocean viz may limit you to a few feet.

AOW, or more likely, the Navigation specialty, will teach you about the compass and kick-counting. But techniques like terrain identification, leaving 'bread crumbs' (turn a shell upside down and leave it on a rock) will also be discussed. Keeping a map on the way out can be a help.

Search & Recovery will discuss search patterns.

When you consider the variable current, underwater navigation is a little questionable.

Richard

 

[theduckguru]

Well, other than the fact that you can see to the horizon in a mall and you don't suffer from the mask induced tunnel vision. The ocean viz may limit you to a few feet.

AOW, or more likely, the Navigation specialty, will teach you about the compass and kick-counting. But techniques like terrain identification, leaving 'bread crumbs' (turn a shell upside down and leave it on a rock) will also be discussed. Keeping a map on the way out can be a help.

Search & Recovery will discuss search patterns.

When you consider the variable current, underwater navigation is a little questionable.
Richard

Each error of 1 degree will have you off course 1 ft for every 60 ft traveled. You'll have to guess what the unknown current speed and direction is going to do to your calculations.

 

[Sinbad the Diver]

You can use kick cycles, air pressure, and time. I normally use a combination of all of them. as a new diver kick cycles is the easiest for short runs. You can get more accurate by measuring the distance you travel during a cycle and using that pace. You must though be consistent and have very good control of your buoyancy and trim or accuracy will suffer.

That's very similar to the problems with compas and pace count navigation on land. Stide length over varying terrain varies greatly, so it's not an exact science.

OP, the other thing you should note is that in most situations underwater nav with a compas is not as useful as nav on land. I believe we learned in similar surroundings (land nav range at Benning perhaps?). Underwater you won't have a map or the ability to determine exact location. And other than in your underwater nav class, rarely will you be given distance and direction instructions. I've found the most use I get out of my compas is setting a bearing on the general direction of a travel which allows me to determine (coupled with terrain ID normaly) the way back to the entry point even after swimming around in circles.

 

[Herk_Man]

Just check out a coral structure map from your dive shop for the reef you are diving. It will have detailed diagrams of the various corals you will encounter as well as descriptions of each fish's territory on the reef. You really can't get lost carrying one of those.

 

[MauiScubaSteve]

Each error of 1 degree will have you off course 1 ft for every 60 ft traveled. You'll have to guess what the unknown current speed and direction is going to do to your calculations.

Proper use of a compass in a non-static fluid environment requires the use of landmarks. By using landmarks, the current/surge error is minimized with regards to degrees. There is still the differences in distance measurement due current/surge that can only be approximated.

As long as you get close enough to visually identify and then reach your intended destination, you have successfully navigated.

 

[theduckguru]

Proper use of a compass in a non-static fluid environment requires the use of landmarks. By using landmarks, the current/surge error is minimized with regards to degrees. There is still the differences in distance measurement due current/surge that can only be approximated.

As long as you get close enough to visually identify and then reach your intended destination, you have successfully navigated.

Low visability is also a factor in the category promoting errors.