Salt Water Weighting verse Fresh Water

[Walter]

As far as weight i usually use 22 lbs here with a 7mm one piece and there i used 18 lbs with a 3mm shorty.

You must have been grossly overweighted with the 3 mil.

To calculate exactly weigh youself in full gear with fresh water weights and all gear that you normally carry. Multiply this weight by .025 and add to your known fresh water weight.

This is the answer. Of course, it only works if you use exactly the same gear. If you are switching gear (different tank, dry suit to wet, different thickness of wet suit, etc,) you need to actually get in the water and do a weight check.

 

[BrianV]

I usually do 6lbs more.

 

[scubaaaronh]

You must have been grossly overweighted with the 3 mil.



Oops 16 lbs
Actually no i had on just enough to start to sink me with an exhale. same with the new 7mm. But i forgot and actually just thought of it i had lost weight since the trip so that would change the whole weight isuue. Guess i'll have to refigure my weight when we go next year. Hopefully i can drop another 25 lbs by our trip.

 

[laserdoc]

3mm suit,I weigh 200 lbs,5'11" 10 lbs fresh water,16 lbs salt
Going to St. Lucia the end of July going to try to use 14lbs ,,,,we shall see

 

[boulderjohn]

3mm suit,I weigh 200 lbs,5'11" 10 lbs fresh water,16 lbs salt
Going to St. Lucia the end of July going to try to use 14lbs ,,,,we shall see

Different strokes for different folks, I guess.

I am roughly the same size. When I wear a 3mm suit in the pool for instruction, I usually use 8 lbs so that I am overweighted enough to deal with issues. If I do a true weight check with that much on, I will sink like a stone. If I wear a 2.5 mm shorty in the pool, my weight check is perfect with no weights at all.

I have not done a lot of salt water diving in a 3 mm because in the tropics I usually used my (now baggy) 0.5mm suit. With that, I used either 6 lbs or 8 lbs, depending on the BCD I was wearing and the weight combinations available on the boat. In the 0.5 mm suit, I once had a buddy who who was floaty, and I gave him one of my 4 lb pockets and finished the dive with 4 pounds without too much trouble. I will dive the tropics in a 3 mm for the first time in a couple of weeks, and I will start my weight check with 10 lbs.

The difference is in your breathing. Many divers are swimming around with giant, fully filled life preservers in their chests. Exhale some of that stuff and see what a difference it makes.

 

[Santa]

Just for sport, and please don't kill me cos my math usually stinks but ...

Theoretically, say that at x kgs of lead + a specific kit + you, you are properly weighted for fresh water.

Couldn't you just multiply that x number with 0.03 or something like that to be properly weighted for salt water - just to errh ... compensate for the added buoyancy.

Or maybe weigh yourself wearing everything and then multiply that number by 0.03 to see how much extra weight is needed.

Am I obsessing with this 0.03 thing?

(I need to read up on this quite a bit I guess, but it seems to me that it should be possible to somehow calculate the difference once you've established a specific person in a specific kit at a specific weight in fresh water. At least in a theoretical setting. Which I'm obviously not cut out for right now ;0)

Have a nice day.

 

[desiredbard]

Good morning,
Just another question regarding my upcoming Bonaire trip. I've done most of my dives in fresh water quarries here in Ohio. Is there any calculation on how much weight you can normally get rid of in Salt water verse Fresh water?

Thanks
David

Ps. I'm not used to warm water diving does anyone normally wear a drysuit in warm water? I was going to leave mine at home for this trip.

I never dove fresh water, is there anything to see in fresh????

 

[Charlie99]

Theoretically, say that at x kgs of lead + a specific kit + you, you are properly weighted for fresh water.

Couldn't you just multiply that x number with 0.03 or something like that to be properly weighted for salt water - just to errh ... compensate for the added buoyancy.

Or maybe weigh yourself wearing everything and then multiply that number by 0.03 to see how much extra weight is needed.

Am I obsessing with this 0.03 thing?

Post #7 in this thread, by DKKTsunami gave the very appropriate recommendation of adding 2.5% or 0.025 times the TOTAL dive weight. Total dive weight includes you, plus everything that goes in the water with you --- lead, gear, and tank.

The reason you have to weigh everything, instead of just x kgs of lead is that you and your whole kit are all immersed in the saltwater and therefore have higher buoyancy.

2.5% can also be expressed as 1 pound per 40 pounds of total dive weight. (Or 1/2 kg per 20kg of total weight.) Considering the 60 pounds or so of typical tank + gear weight, the other poster that just says "add 6 pounds" is pretty much on the mark for a typical sized diver.

It's a bigger problem to be underweighted than to be overweighted by a couple pounds, so I tend to add 7 pounds when going to saltwater and subtract 6 when going from salt to fresh. Or we could use the 0.03 that you obsess about.

 

[SCOOBA PHAN]

Just Take An Educated Guess Then Get In The Water And Fine Tune It. Every One Is Different, No Formula Will Work For Everyone, Especially Since You Will Be Using Different Gear. As You Get More Experience There You Probably Will Be Able To Use Less Weight As The Days Go By. Same Goes For The Wetsuit. 3 Mil Will Keep You Warm Enough, But If You Need To Cool Off You Can Add The Water As Mentioned Above. Have A Ton Of Fun.

 

[Santa]

Oh right - missed that, thought I'd read it all.

Knew there was a reason for the 0.03 though ;0)