underwater navigation

Niamh · July 1st, 2006, 08:14 PM

Hi everyone

I was too embarrassed to ask the dm this question yesterday, especially seeing as I was last on the boat and held everyone up- after a long surface swim I might add. My problem is with navigation and getting back to the exact spot where the boat is.

I understand the concept of counting your kickcycles- but how could you possibly enjoy your dive if you're at that lark! so what I want to know is, say for example I swim North for a while and then west. Do I have to retrace my steps exactly by turning around and swimming east and then south and time how long I swam for each direction or how do I do it? There doesn't seem to be many obvious underwater features that I can use as a guide in the waters i find myself in, and so always overshoot the boat and end up snorkling back. My buddy seems to be in the same boat as I'm in (well the one we're both trying to get back in..)

Also, does anyone ever tie a marker to something just directly under the boat so you might see it before you swim past your exit point or is that just sheer madness? Any help will be gratefully received.
Niamh

greg27 · July 2nd, 2006, 06:53 AM

the answer is simple cheat do your dive [into the current of course] and after your safety stop at 15 feet then you or 1 person in your group sign me , look boat. surface give the ok signal in case anyones watching from the boat take a compass heading drop back down to 10/15 feet and swim right back to the boat p.s.let the others in your group know ahead of time what your doing and agree upon whose going to do it

Walter · July 2nd, 2006, 07:15 AM

Unless you are very familiar with the site (it doesn't sound as if you are) retracing your steps is a very good idea. Instead of starting your dive under the boat, start it at the anchor. You should be able to recognize it on your return.

It is likely (although I don't know where you are diving) that there are recognizable features at your dive site, but you've yet to learn how to distinguish them. When we first start to explore underwater, we are like the city boy in the woods for the first time - everything looks the same. There are lots of differences, but we need to learn to see. Also, things often look different from the other side, turn and look behind you from time to time, so you will know how the features will look on your return trip. Keep in mind your depth. If you see a landmark at 60 ft and think you see it on your return at 40 ft, it's not the same feature.

rickydazla · July 2nd, 2006, 07:59 AM

Or indeed like a country boy in the big smoke - all the buildings may look alike but pick out the obvious features and at the end of the day if you need to ask a helpful passerby the way back to the car park because you're a bit lost, who cares? Eventually you will learn to find your way round. My gran lived in the same town all of her life but could only navigate her way round by going to and from the bus stop to other places, not from one place to another... Does that help? Probably not...

Niamh · July 2nd, 2006, 09:35 AM

thanks for yer help people. I'll try harder next time.
Niamh

SteveAD · July 2nd, 2006, 09:46 AM

find a good instructor and do an AOW or NAV course you can learn some tricks that would otherwise take dozens of dives to figure out.

scubabrn · July 2nd, 2006, 02:40 PM

Has anyone done the SSI navigation course. My wife and I both are at 48 dives apiece and our nav skills can use some work. Just wondering if it is worth the dough.

rickydazla · July 3rd, 2006, 02:30 AM

Quote:

Originally Posted by scubabrn

Has anyone done the SSI navigation course. My wife and I both are at 48 dives apiece and our nav skills can use some work. Just wondering if it is worth the dough.

I teach it and beleive that mine are worth the dough! I try and focus on real-world application of skills as relevant to where and how students are most likely to dive in practice. Compass navigation of squares, triangles et al is all well and good, as long as you get a chance to practice it in a variety of situations during the course (on a reef, on a wreck, from a beach/shore, from a boat, in limited vis) and are made to think about and discuss how this may be useful for you in the future. Same goes for natural navigation. Ask your instructor to be some pertinent questions based on the above and see what you think within the framework of how good your navigation is in non-diving scenarios; like giving directions as a passenger in-car using a map and retracing your steps around an unknown town/city that you are visiting.

hvulin · July 3rd, 2006, 06:08 AM

Go down by the anchor (and remember your depth)!

If it's a slope or a wall this will help you find it:
1. get back to the same depth and head back to the boat
2. "back to the boat" is defined as: if shalow part was on your left when going in one direction, it will be on your right when heading back

If it's all the same depth remember the current (and direction, but remember that it can (and will) change), big stones, old nets, position of the sun (when heading back it will be on the other side) or moon, and use the compass. Before changing direction take a look back and remember what you see....

Take care of time, remember when you descend, calculate time when you start heading back (but take care of the current because it will speed you up or slow you down) and you will know when you ARE back!!!

This are just a few of the tips that come to my mind....

Niamh · July 3rd, 2006, 08:44 AM

Thanks hvulin

Was in your part of the world last year, really beautiful. Didn't get to dive there unfortunately, only snorkled but still really enjoyed it. Will use your advice. Hvala

Niamh