Navigation?

[Crunch]

How do you navigate under water? I assume you can't really work out where you are going? Do you have a compass or something?

I was thinking about this today at work (really starting to get interested in doing my OW) and I thought a compass would probably do it, but how can you tell if you've strayed off course? Does this happen often?

 

[MikeFerrara]

A compass is used. Natural navigation which is using visual references to land marks or other features. Just like on land compass navigation is combined with natural navigation. Lines are sometimes used. Directional error is sometimes managed by using intentional error...purposly going a little off course to hit some feature that can then be followed...ie if I head west of the target and then come to the "feature/structure to be followed" I know I have to turn eas. By contrast, if you try to hit it dead on and miss, you may not know which way to go.

It's really not much different than land navigation where visability is limited.

 

[95yj]

I live by my compass underwater. The last thing I do before jumping in is take a look at my compass bearing. Unless I am following a wall or am someplace I've been a thousands times, I glance a the compass everytime I check air and depth.

On land, you can blindfold me, spin me around and I'll have no problem telling what direction I'm facing. Underwater I can be off by as much as 90 degrees when swimming a slow circle around a large object.

 

[vablackwater]

A compass is part of the equation. So is your depth gauge (even using your ears to tell you if you are descending/ ascending). Natural landmarks, slope of the bottom, familiarity with an area (ie change in bottom sediment from sand to rock), direction of current (ie understanding set and drift), a change in the type of vegetation, temperature changes... all depends on where you are diving.

Navigation is the art of using all available means to resolve ambiguity in terms of position.

 

[thomjinx]

In using UW compass navigation, what is usually taught is to count the number of kicks you take in a given direction. By doing this, you can return on a 'reciprocal' course ,or navigate a square or rectangular course using a compass, as long there isn't too much current, or you are able to adjust to compensate for it.

As others have stated, you also use natural landmarks (seamarks?) and features.

I am a private pilot, so I learned to navigate by compass that way. A compass is one of the most reliable instruments you can have, but it is affected by metallic objects and variations in the Earth's magnetic field.

Once you learn how to adjust your 'crab angle' for current, you can do some pretty serious navigation with a compass. Especially if you have a reasonable accurate map of the area you are in.

Much more reliable than "turn left at the big grouper"

Recently in Thailand, the group my buddy and I were supposed to be with took off before we were even in the water. We were dropped off at one pinnacle and were to be picked up at another one some distance away. The vis was not so good, and my buddy was stressed when we couldn't find our group at the first pinnacle. Fortunately I had looked over the map of the site before the dive, and was wearing my compass. I was able to successfully navigate between the 2 pinnacles to where we were to be picked up. There was some current, so I had to add a few degrees of correction to the direction I wanted to go, but we swam straight to the 2nd pinnacle without having to search for it. Impressed the hell out of my buddy!
I was really glad I had checked out the map!

Buy a good compass, get some instruction on UW navigation, and practice with it. It is a very usefull skill....essential in some places!

 

[Twiddles]

Truth in fact is that although the compass can help you navigate underwater and is an aid it cannot often be used alone. Unlike on land your moving in another dimension (vertical plane) and the combination of current, surge and variances at diffrent depths make it very unlikely that you could even come close to navigating underwater as you do on land.

The best method that has worked for me so far is point hopping: sight, target, move to that location, site, target continue then reverse. Kick cycles might work in a pond or even in a lake or away from currents but if your square, triangle etc is of any real size the only thing your going to be doing when you reach your end count is looking around and finding you are not where you think you should be.

A pattern not often discussed but by far the easiest to implement is the star because its a straight shot out and back before you change direction and on each return your familiarity with your start point increases.

 

[TSandM]

As has been said, navigation underwater is a combination of compass work and observation of one's surroundings. In poor visibility, extremely precise navigation is difficult to impossible, and when it is critical to find something small (for example, to get back to an anchor line to go up to the boat, when the anchor is set far enough away from the wreck that you can't see one from the other) you can use a reel and line to find your way.

Most diving is like horseshoes and hand grenades -- close is good enough.

 

[Debay777]

if your proficient with a compass on land, you can navigate underwater.

 

[almitywife]

I can navigate around the biggest shopping centre in the world and still make it back to my car

underwater! im just paying attention now and finally using a compass...... only got lost once so far, but is it 'lost' if you know youre heading in the wrong direction and your compass is stuck?

 

[vablackwater]

i am the opposite, i can find the most rural farm pond or body of water to jump in, but give me directions to the grocery store and I am lost for hours.

Go figure