Fishlips_1:
Being a newbie to SCUBA, I have started my AOW, but my instructor dive masters and does the servicing for a dive resort in Rotan, and will be there for a month. On land, I have a pretty good sense of direction, but under water my sense of direction kinda stinks. Any tips? Would appreciate any helpful hints.
Lips
I've made a few posts about navigation in the past and I'm starting to work it into a bit of an article. I'm not finished with it yet but here is part of the raw text (it's a lot of text and a little bit disjointed at this point).
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Orientation: First of all, you need a mental map of the site. If you don't have a mental map you're going to get get lost. So before you go in the water you need some basic information. If it's a shore dive, which way (on the compass) is the shore? How deep is it? Is the bottom regular or irregular? does the slope of the bottom follow the shore or is it flat? Are there any landmarks (small wreck, unusual features like a bow net or something) that you can "recognize" when you see them? That kind of thing. The best way to find this information is to either on the internet or better yet by talking to other divers who have been there before you.
visualize your dive: Know where you want to go and how you'll get back. Think about your turn pressure and turn time and the pattern your want to swim before you ever get in the water: For example, before I get in I know if I'm diving an out and back pattern, left, right, how long, how deep and where I want to come out at the end. It helps a lot when you're first learning how to navigate on your own to enter and exit at the same place and I'll assume for the rest of this post that this is what we're doing.
Compass: Next, once you're in the water, and this might sound funny, try not to navigate too much with the compass. What I usually do with the compass is to set it before I descend to point at either the shore (if that's relevant) or in the direction of where I want to exit. My navigation plan and the setting on my compass are linked and unless I'm running search patterns for something my compass tells me only one thing...the way home. After that, I use time and bottom features to get around and the only time I use the compass to see which way I'm going is if the bottom is totally flat. Once again, the mental map and visualizing your dive are important to how successful you are in this.
Land marks: : When you're swimming, look around and pick out some landmarks (an old tire, a bit of junk, an odd looking rock, anything that doesn't move). You only need one or two but when you have a land mark make a mental note of the depth and bottom-time when you saw it. Why? Because often times you'll see it on the way back too. Say you don't have any current and you see a good landmark after 10 min. Then you swim past it for 10 min and turn around on the way back you'd expect to see your landmark after another 10 min and you'll reach the exit 10 min after that.
In other words...... Get ready for Rob's golden rule of navigation.....
Your bottom timer is your most important navigational instrument. Not your compass.
Tempo: say for example that your tempo isn't constant. This can happen if you become distracted or you're swimming in current. In this case, a land mark close to home is your best friend. Pick one a few minutes from the exit (max 5-7 min swimming). In current you may need to search around for it on the way back (it may be closer or further than you thought it should be) but when you do find it you *know* for sure that you're only 5-7 min from the exit. After seeing that landmark you can ascend to safety-stop depth and keep swimming toward your exit having done the safety stop while swimming (easier in current) and you're guaranteed to come out close to home. Using this technique I can almost always come out within a stone's throw of where I started even in a current.
Turn pressure: Say for example you're swimming out-and-back. Say you swim out at 15 metres and turn the dive at 110 bar and swim back at 10 metres gradually working up to 5 metres for the safety stop. Your pressure isn't going to tell you when you're there because your depth fluctuated. What you need to do is note the bottom-time when you turned and use your clock to tell you when you're back again. For example, in the dive I just mentioned, you may have 110 bar when you turn but if your bottom time is 27 min then you know that at 54 min you're back again. In other words pressure can control the dive but your still need your bottom time to navigate.
Lead, don't follow: practice isn't enough. Lead the way. Every dive you make under supervision hurts the development of your navigation skills. This also applies if your buddy is navigating. If you want to become a homing-pigeon then you need to be in charge.
dive planning and navigation are not separate skills in the real-world.
Current. Tidal waters usually have some current and you can use this to know your compass direction. For example, if you're diving in a tidal inlet and the tide is going out then the direction of the current shows you which way the mouth of the inlet is. This, like many of the other techniques requires to you have a mental map of the site before you start. Where I live the current usally runs parallel to the shore too so it makes orientation easy. Next time you dive look at which way the current runs.
Depth. If you know how deep various parts of a divesite are then you can problaby locate yourself on a mental map using depth. Deeper is often away from shore and shallower is often in the direction of shore.
Sand. Sometimes sand will ripple on the bottom. It usually does this parallel to shore.
Look ahead. Swim from object to object under water (like rocks, or even from one starfish to the next), don't just put your head down and go. Most people will swim in circles with their eyes closed (or head down) and after a short time you won't know which way you're swimming any more. Swimming from object to object keeps you going in a much straighter line.
mmmmmmmm. Can't think of any more that use a lot.
the compass. When in doubt use a compass. I recently had an experience of getting flushed into a shipping lane on a deep dive. We swam mid-water for 25 min on a compass with no references and in heavy current to get back to the shore and we ended up only about 50 meters away from the entry point. It takes practice and it takes "trust". You must trust your compass even if you "feel" like it's the wrong way.
Most of these techniques are covered in a decent navigation course.
R..
