Underwater Navigation

[AmRus]

I have completed the necessary dives and passed the courses in order to receive my master dive certification from PADI.

During almost all of my previous dives, I was always part of a group of holiday divers who were closely monitored by locally trained PADI DiveMasters: plan the dive, dive the plan. It's the rule. (Okinawa, Cyprus, Maldives, Red Sea).

What I've found is that now, when I'm allowed to go on my own with my dive partner, and afterward to meet up with a RIB or onto the boat - I can follow the safety stop rules, including for deep dive -I really haven't a clue as to where I am when underwater on boat dives. I attend the pre-dive briefings and take notes, but underwater - it all goes amiss.

On a recent dive trip (live-aboard), my dive partner used up more air than me and I was tasked with bringing the person to a safe dive conclusion. The DM signaled to me to end the dive with my partner and recover via the RIB, while the rest of the group continued the dive. It was a pre-arranged plan and I didn't realize I would have this location problem. I have a sausage for identification, but - seriously - I couldn't confirm where we were on at the time. Safety stop, sausage deployment... no problems. Where we were - I haven't a clue. RIB guy did. DM did (of course): Me? Not a clue.

This is not especially a safety issue: the DM's I have dived with are superb - it's more of an embarrassment. (We were in the Red Sea: had the DM thought there would be an issue regarding dive conditions, we all would have surfaced, but we were in no danger on a calm, clear day and HE knew we were in sight of the boat, which we were when my partner and I surfaced).

I am completely disoriented underwater. I really think I passed the AOW part of navigation only by luck.

I have a Suunto D9 - perhaps I should buy a dedicated compass? Retake the underwater navigation course? I don't talk (much less 'brag') about my certification: I completed all the certs because I really love the sport.

Any suggestions - apart from telling any local DM that I'm a complete git in the water, or not diving again? I'd really like to solve this problem.

 

[TSandM]

I have the same problem with boat dives in unfamiliar places!

You can do a lot of navigation using natural features. For one thing, if you are diving off an anchored boat, make careful note of the depth where the anchor is sitting, and what the terrain around it looks like. (For example, is it sitting on top of a knob, or on a flat, sloping bottom, or in a pile of boulders?) Where the bottom has a distinct slope, you can pay attention to whether you are swimming with the shallow side on your right or on your left (getting home is the reverse). Most of our Red Sea dives were either on or near walls, or on sloping bottoms (or on wrecks, which are their own navigational landmarks). A compass is helpful if the visibility is too poor to orient on surrounding landscape, or if the bottom has very little slope or is extremely irregular.

Time can also be useful. If you know you swam 20 minutes in one direction, then the anchor line isn't likely to be more than 20 minutes back (unless you were swimming with, and then against the current).

Noting unusual features that you pass can help reassure you, too. I've even been sure I'd found the spot for the exit because we swam over the same furious nest-guarding fish we passed on the way out! My husband did some navigation in his IE by nudibranch But anything that's likely to stay put and be recognizable is a way to reinforce your orientation.

I guess what it comes down to is that good navigation requires pretty good situational awareness, which means noticing more of what's around you than the particular fish or coral or sponge that's caught your eye. As a guided diver, you don't have to do this much, but as an independent diver, it's key.

 

[fisheater]

Hence, my advice is to go diving without professional dive guides. Lose the training wheels.

Are the local dive sites and local divers with whom you can practice the navigation skills taught in the books?

 

[AmRus]

Thank you. I will pay more attention to my surroundings - your comment on being a 'guided diver' really hits home. I love diving in the Red Sea (one week live-aboard for two years) and will be sure in the future to use dive time as a guide. I think I could get lost in a closet...

 

[AmRus]

You are right, of course: "lose the training wheels". I can almost hear one of my instructors telling me this. Thank you for saying that. Unfortunately, I don't have many opportunities to ... oh gosh, I can come up with many more excuses, can't I? You are right and I appreciate your input - I'm not deficient, just deprived of diving experience (I hope).

 

[Ber Rabbit]

An addition to what TSandM posted: When you swim away from the anchor line, turn around and look at it from a short distance away. You may remember it was next to an outcrop of coral but you want to know what the outcrop looks like from the direction you will be heading on your way back. It's also nice to know what's beyond the anchor line so you can have a complete picture in your mind of what the surroundings should look like as you near the line.

A side note from an experience my husband had many years before he met me. If you are at the area where you are certain the anchor was, check for drag marks. It's possible the anchor has moved. If you find drag marks and they end with no anchor, beware. While my husband and his buddy were gesturing that the anchor should be there they heard clanging, the boat had drifted so the crew pulled anchor and had returned to their original spot and re-dropped the anchor. It hit the sand a few feet from my husband and his buddy.
Ber :lilbunny:

 

[TMHeimer]

Two things I've learned in my limited boat diving times-- First, rule #1 is do whatever it takes to remember where the anchor line is. Maybe a compass heading (unless on a metal wreck), maybe distance from a point on a wreck or edge of reef, whatever. Maybe just looking backwards when leaving the line and occasionally after that. The other thing was when I was with a DM and the anchor was in sand about 50 ft. from a big round, rock-like reef. We both couldn't find the line to ascend and he said we probably should've just run a line from it at least to the reef.

 

[RTee]

In addition to the comment made by TSand M...I would say you should not only note the time but also the general heading the DM is using right at the start of the dive and write both down on a slate. When it is time to go back...add or substract 180 and travel a pd of time equal to what you just did. Everything being equal...no current, same general speed, etc you should be able to get back to the general area of your starting point.

 

[AmRus]

Cheers, Mate. That makes a lot of sense to me. It may be 'common sense' to everyone else, but it's something I will now do - take a compass reading off the boat line and mark the time. Thanks!

 

[Doubler]

My first thought was Master Scuba Diver can't find the boat WTH. Then I began thinking about it. My wife is always amazed that I bring her back to the boat each and every time. She has almost 1000 dives and will admit she couldn't find the boat if you dropped it on top of her. She DEPENDS on me to perform that function as you do the DM. Suggestion if the DM goes left You go right. We do this every dive mostly because I hate diving in a crowd and as a photographer don't want people waiting for me. When you get in the water note the depth under the boat, this is your target return depth, Note something about the site, note how far it is to the wall or whatever it is you are here for. Take a compass heading. As you are moving away back check to see what it looks like coming back. Have confidence. When you get to the target depth on your return and target area begin looking up for the boat shadow. Remember boats swing. If you are sure of where you are at and the boat is not to be seen, be confident, due your safety stop and don't be surprised when the boat swings back over you. There is no Underwater Navigation course in the world that will teach real world scenarios. They familiarize you with concepts. You take the concepts and teach yourself navigation. Practice makes perfect.