Navigation / Positional Awareness

[Aloha Joe]

What are your techniques for knowing your location relative to entry/exit points? For example, what do you think about before the dive, what do you consciously look for, and how do you keep track of it all?

I recently turned down shore diving with a buddy because I wasn't comfortable leading dives at unfamiliar sites, partly because of having to navigate. I understand the basic concepts but struggle putting them all together. I'd like to hear what works for you so I can start practicing during my specialties and upcoming dive charters.

Thanks

 

[TMHeimer]

Though I've taken the NAV course and am capable of doing the squares, triangles, going on this heading or that, my shore dives are very simple (and I know the sites, of course). I generally like to go out to the right on an angle. I simply aim the compass that way and follow where the arrow points (if it point SSE, I try to keep it pointing there). Then I take a left turn and another left to return to shore. Then on 2nd dive out and to the left, same idea.
If it's sunny I may forget the compass and keep the sun where it was when I descended and began on my desired direction.
I will not hesitate to ascend from 20-30 feet to see where I am--ie. how far from shore. I sometimes do this more than once since I tend to get turned around a lot hunting for shells, fish to poke spear.
Most of my boat diving has been on wrecks and I almost never use the compass, unless for some reason I venture out from the wreck a bit. Most important thing there is remembering where the anchor line is--I don't take a heading for that, and just tust my memory. Couple of times my memory failed.

 

[boulderjohn]

It's complicated because to a large extent it depends upon the site. Some sites are so easy anyone can do it without any extra training. Others can be quite complex. A full answer would require quite a bit of space.

I know because I created a distinctive specialty called advanced dive planning, and I know how many pages I put into that topic.

 

[tursiops]

If I'm at an unfamiliar site -- whether guided or not -- I try and carry a slate and make notes. Things I try to write down are significant features and their depths, time swimming a certain direction, noticeable currents and their directions, and especially...what it looks like underwater when I turn around and look at where I entered.

 

[boulderjohn]

Here is an example of some site specific navigation. It begins with the planning knowing little about the site and then switches to what we know now. In this case I am talking about deeper depths and other conditions than you are going to encounter--what I want you to focus on is the problem solving aspect of it for that specific ste.

Our goal was to reach a certain point in a very deep (about 280 feet) lake. We knew it would be very dark on the bottom. We had a descent line running down the east wall, and we knew that ended at about 190 feet deep. We knew there was some line running along the bottom heading northwest down an incline for a while before ending. Our problem then was to swim past the end of that line to a turning point and then return to the east line so that we could do our ascent on that line. Our concern was that if we just followed a compass heading south east, the odds were very good that we would miss the line by a few feet, not see it because of the darkness, and not know which direction to go to find it.

Our solution was to head more east than south, eventually running into the wall. Once we hit the wall, we followed it south until we ran into the line. In other words, we purposely missed the line by a wide margin so we would know which way to go when we hit the wall. It worked perfectly.

We now know that area well. If we were to just blunder into pretty much any part of the lake and wanted to get back to the east line, we could find it easily. That is because we now know what we did not know before--the east line is on the crest of a big hill. All we have to do is swim roughly in that direction and head up the hill. Piece of cake.

 

[flyboy08]

A sandy bottom can also provide clues as to the direction of land....ripples run perpendicular......timing and current are two most important factors....take a nav class and you can play practice in your yard blindfolded even....

 

[scubadada]

You wouldn't believe the number of divers who do not pay attention to the depth and identifying features of where the boat is moored. Knowing this, it is almost impossible to miss your ascent. Of course, saying that, I'm a drift diving fan. Go down, swim around, ascend, get picked up by your boat.

 

[tursiops]

A sandy bottom can also provide clues as to the direction of land....ripples run perpendicular

Not sure what you mean by perpendicular, but studies show that the orientation of sand ripples changes with changing currents and waves, and they are constantly moving and migrating and rotating. I think what you mean is you swim perpendicular to the ripples to get to shore....but that could also take you in the opposite direction, i.e. away from shore. and if the ripples are not parallel to the shore, then that is an added problem. So, yes, maybe a clue, but not one I would bet my life on. Best to use more stable and reliable indicators.

 

[flyboy08]

Not sure what you mean by perpendicular, but studies show that the orientation of sand ripples changes with changing currents and waves, and they are constantly moving and migrating and rotating. I think what you mean is you swim perpendicular to the ripples to get to shore....but that could also take you in the opposite direction, i.e. away from shore. and if the ripples are not parallel to the shore, then that is an added problem. So, yes, maybe a clue, but not one I would bet my life on. Best to use more stable and reliable indicators.

No...one must orient that on the onset...take notice while swimming out as the chance of the ripples changing during an hour Dive is remote.

 

[shurite7]

Two things come to mind: maintaining good situational awareness (pay attention to your surroundings [especially when using the environment], depth, compass [if using one], air consumption, and other divers) and keep in the back of your mind where the exit is, especially when you change directions or when diving in currents.

Avoid being the type of diver that gets in the water not paying attention as to where he/she is going or forgetting to keep track of where the exit is. The simpler the plan the easier it is to keep track as to where you are. More challenging sites require more dive planning and diving that plan. In short, become the thinking dive rather than the just doing diver.