will soon be doing first saltwater dive

[Becca65]

As I've mentioned in other threads my husband and I got certified last September - since then we've made several trips to dives lakes and a river (and cleaned the bottom of a friend's pool ) In the next few weeks we will be doing a "rig dive" in the Gulf of Mexico - plan to descend on a line - wondering how much weight I should add - is there a standard? I've been told by some friends that they double the weight they use in fresh water when they dive in saltwater.
Also - not sure that we'll come across any - but what exactly do you do if you're swimming around and happen to see a shark? Do you continue swimming without any fast movements or turn and go another way or what?

 

[lowviz]

Double the weight? Way too much. Try adding 4# and even that is probably too much for you.

Sharks, count yourself lucky if you see one!

 

[drbill]

Not sure what thickness wetsuit you'll be wearing. Here in SoCal where 7mm is the common thickness we usually go by a rule of thumb that you should use 10% of your body weight plus 5-7 lbs of lead. If you're wearing a 3mm there, it would be less.

 

[diver 85]

Oh, she'll see one--------or a dozen, they are there.....Becca, just continue you're 'regular' dive plan, 99% are harmless---so you have the odds in your favor..........Please report back & tell us how everything went..........

 

[nolatom]

Going from fresh to salt with a 3mm full suit, I can add about 2 pounds. Your mileage may vary.

Sharks are generally seen as "good". We just watch them. And I usually don't turn my back on them when they're close, just in case, but you'll want to look at them anyway. What's more interesting than a shark? ;-)

I too dive the Gulf. Rig dives are fun! Lots of creatures, marine growth, and easy to stay oriented as to both direction and depth with the structure around you.

Descending on a line is pretty standard. You can descend as fast as you can equalize your eardrum pressure, so you can pull yourself down the line as you equalize. You'll get "heavier" as you get deeper, so once you see the rig, pop a little air into your BC, then a little more, think of your inflator button as an "air brake" that slows you gradually to a "stop" (buoyancy-neutral) as you get to your chosen depth.

 

[Becca65]

wow - have to say replies to posts here come really fast - thanks! The "air brake" analogy is a good one. I was thinking doubling my weight was a little much - and since I've been diving with 12 pounds in fresh water wasn't really looking forward to diving with 24! As the water is warm here in the Gulf at this time of the year I'll probably just be wearing my 3mm (I think - maybe it's a 2mm - will have to check when I get home) shorty when we dive.

 

[CT Sean]

You need to weigh an extra 2.5% to go from neutrally buoyant in fresh water to neutrally buoyant in salt water. By "you" I mean you and all your gear. If you weigh 200 lbs (150 lbs for you (if this is an insult -I'm sorry, if it's a compliment, you're welcome ) and 50 (bc, tank, reg, weights fins, etc...) for your gear) you'd need to add 5 lbs for salt water, which I'd round to 6.

 

[CelticLemon]

Here is an easy basic weight guideline reference: http://scubatechphilippines.com/scuba_blog/wp-content/uploads/2011/07/weighting-guidlelines.jpg

Hope this helps and you have a great time on the rig!

 

[nolatom]

Guess "heavy" at least to start, you don't want to be too light as you'll never get down and then it's hard to hang at 15' safety stop when you are even lighter with a more empty tank.

Then reduce the weight little by little. The real test is if you are able to be neutral at the safety stop with BC empty.

 

[wolflegresley]

If your already weighted correcty for fresh water you should add weight based on your current body weight as follows:

Body Weight - Weight to add
100-125 lbs 4lbs
126-155 lbs 5lbs
156-186 lbs 6lbs
187-217lbs 7lbs

This is right out of page 7 of the PADI peak performance buoyancy book.