Question Search & Recovery vs Underwater Navigation

[Orso Raggiante]

I have always marveled at divers who basically show up at a dive centre, pick up their cylinders, and go off to dive at a particular site. I wouldn't know how to get to, say, a wreck, if I had dived that site just that morning! So I was thinking of doing either a Search & Recovery specialty or an Underwater Navigator specialty to help me locate myself and the things I want to see underwater. Does anyone have any recommendations as to how I can achieve this, or perhaps tell me the difference between the two courses mentioned? Both seem to teach some amount of measuring distance, knowing directions, and remembering features. Thanks in advance!

 

[BoltSnap]

1. Navigation

2. Wreck

3. Deep

4. Nitrox

5. Limited visibility and night diving

6. Perhaps S&R but not essential unless you are going to be recovering things.

I am talking above about "REAL" courses not just getting c-cards without substance.

 

[Capt Jim Wyatt]

Navigation. Talk to the instructor to see how comprehensive the class is. Some are great, some suck. Evaluate their ability to navigate with a compass, fin kicks and natural navigation and a combination thereof.

Ask your instructor which way the north indicating arrow points on a magnetic compass.

Ask him what the magnetic variation is around the places you will dive. He may not know the number but he should be able to tell you how to find that number.

 

[ADVRider808]

Ask him what the magnetic variation is around the places you will dive. He may not know the number but he should be able to tell you how to find that number.

I'm always sadly amazed at how many times I've asked this and gotten the "deer in the headlights" look followed by a slight stammer in speech as the person tries to quickly cover for their blissful ignorance.

 

[rob.mwpropane]

I have always marveled at divers who basically show up at a dive centre, pick up their cylinders, and go off to dive at a particular site. I wouldn't know how to get to, say, a wreck, if I had dived that site just that morning! So I was thinking of doing either a Search & Recovery specialty or an Underwater Navigator specialty to help me locate myself and the things I want to see underwater. Does anyone have any recommendations as to how I can achieve this, or perhaps tell me the difference between the two courses mentioned? Both seem to teach some amount of measuring distance, knowing directions, and remembering features. Thanks in advance!

Dive murky water. Use a compass often, get good with your gear in less than stellar viz.

I am by no means an expert, but I think taking away one of the senses (sight) and having to work it out really helps.

Also, diving the same sites help a lot. For example, I dive the same quarry a good bit in between "real" dives just to keep the dust off (it's just what I have locally). I pretty much know where I am just because I'm in it so much, and sometimes the viz is less than 5'.

Also, some of those guys (myself included) that show up to dive a site and look like they know what's going on also get severely lost... it's not always perfect Just when I think I "have it going on" a dive comes along that makes me question if I really know anything at all!

I think time under water trumps most specialty classes, but you do you. Good luck!

 

[Cthippo]

A lot of it is research done beforehand.

Usuly before I splash I have spent a lot of time looking at maps, aerial miages, working a plan out on Google Earth or some such. I will figure out compass bearings ahead of time and sometimes even drop flag buoys.

 

[tursiops]

OP, I've taught Nav and S&R a lot. They are very different courses, both with lots of good stuff in then and a lot of learning possible.
Nav is very compass-oriented, secondarily distance estimation using fin kicks. If someone says "there is a wreck at 330 about 200 feet away" it teaches you how to swim a 330 course and how to estimate when you've gone 200 feet.
S&R is about looking for things and secondarily how to bring them safely to the surface. For the latter there is a ot of lift-bag work. For the former there are various search patterns and techniques depending on the area you are trying to cover and the size of the "lost" object and the visibility. Knowing how to use a compass is helfpul for S&R, so preferably you'd do Nav first.
For your use case, take Nav.

 

[KeelsonGraham]

I'm always sadly amazed at how many times I've asked this and gotten the "deer in the headlights" look followed by a slight stammer in speech as the person tries to quickly cover for their blissful ignorance.

Can’t see the relevance of knowing the variation at a dive site, provided it remains constant. It’s not as if you have to achieve and maintain a specific magnetic track, like aircraft do. All you really need to do (surely?) is to hold a constant heading and find it’s reciprocal within a maximum accuracy of 5-10 degrees.

 

[ADVRider808]

Can’t see the relevance of knowing the variation at a dive site, provided it remains constant. It’s not as if you have to achieve and maintain a specific magnetic track, like aircraft do. All you really need to do (surely?) is to hold a constant heading and find it’s reciprocal within a maximum accuracy of 5-10 degrees

Depends on where you are and what you are doing.

Where you are: magnetic declination varies greatly depending on your location. Variation in Seattle, Washington USA is +15.21 degrees, Key West, Florida USA is -1.88, Antigua is -14.99, Malta is +3.8

Depending on your location and visibility, not knowing about magnetic variation may not matter much. In locations with high magnetic variance and less than ideal visibility a 15 degree variance that is not accounted for could cause you to miss your mark (unless you and the person giving directions were both not accounting for variance.

What you are doing: Let's say you are on the surface and want to mark the spot below you for future reference. You shoot a number of back azimuths to trisect your position for later use with a map. In this case, you will need to account for declination when referencing the map to your azimuths. If you intend to share this data with someone in the future you will need to indicate whether or not magnetic variance was accounted for so that everyone has the same point of reference.

 

[Capt Jim Wyatt]

Depending on your location and visibility, not knowing about magnetic variation may not matter much.

For what we are discussing it does not really matter at all. If an instructor does not know what it is nor how to find it then he is not much of a navigator IMO.