weight question help please!!

[alexmartinezphoto]

So I have only gone diving in fresh water and i will be going to mexico and diving in salt water. I just want to know about how much more weight i should use. Im about 155lb 5'7". I used 6. pounds in fresh water and had pretty good control on my buoyancy. I could have used a little more wieght even, maybe like 2 more pounds. It was taking me a while to sink. So i was wondering about how much more i should use in salt water.

 

[orm]

We find that in fresh water, divers use about half the weight than in salt water.

 

[H20Bubbles]

I am 6', 225, and wearing a full 3mm wetsuit, dive a back plate/wing, and use about 8 lbs when diving in Mexico. I've also worked hard to shrink that number down as many of my first dives there were done in the 14-16 lbs range.

Honestly, the best suggestion I have would be to talk to the DM you are diving with. They have lots of experience with the local conditions and with people and the fact that weighting can vary greatly based on your own experience and gear.

 

[Scott]

What I find works best is to conduct a proper weight check on a shore dive before venturing out on the boat.
You're not being presured by the operator to get down, they're not over weighting you to get you down, you get a shallow dive to help calm the nerves and get used to the feel of the ocean.

 

[Bubbletrubble]

So I have only gone diving in fresh water and i will be going to mexico and diving in salt water. I just want to know about how much more weight i should use. Im about 155lb 5'7". I used 6. pounds in fresh water and had pretty good control on my buoyancy. I could have used a little more wieght even, maybe like 2 more pounds. It was taking me a while to sink. So i was wondering about how much more i should use in salt water.

@alexmartinezphoto: A good starting point is 5 or 6 additional pounds. This assumes that you are using identical gear (same wetsuit, tank, BCD, etc.). The main difference that most people in your situation run into is that at home (in the quarry) they're wearing a 7mm or thicker wetsuit, whereas on vacation (in Mexico) they're wearing a 3mm or thinner wetsuit. There will be a substantial buoyancy difference between a 3mm and 7mm wetsuit. In fact, if this is the case for you, I'd recommend throwing all of the "rules of thumb" out the window and just doing a proper weight check in Mexico.

FYI, on average, the density of seawater is about 2.5% greater than that of freshwater. The aforementioned 5-6 lbs. represents approx. 2.5% of the total weight of you + your rig.
This info is only useful if you were properly weighted for freshwater to begin with. Consult your OW class materials for a reminder on how to do a proper weight check. Most newly-certified OW divers seem to forget how to do this.

What I find works best is to conduct a proper weight check on a shore dive before venturing out on the boat.
You're not being presured by the operator to get down, they're not over weighting you to get you down, you get a shallow dive to help calm the nerves and get used to the feel of the ocean.

That's great advice, Scott!

 

[Altamira]

I have very limited experience in the ocean, but double the freshwater weight as indicated by Orm seems a bit much for most divers. Even though my buoyancy control was not where I want it to be, I found that I was using 10-11# in FW with 3mil suit and @17# in SW which was closer to the approximate 6# increase as stated above. With 22# of weight, I would have been overweighted by a bunch, considering the water difference is only 2.5% of the total weight of me and all of my gear.

 

[alexmartinezphoto]

thanks guys

 

[ajduplessis]

We are about the same size, and I use roughly the same amount of weight. Dive location will have an impact on the amount of weights. Example: Diving in Mozambique is add 2 pounds, same setup in the red sea I add 4 pounds. I always first do a checkout dive with 4 pounds and remove until I find my balance. My weights are 1 pound bullets, making adjustment easy. Cylinder material (steel vs ali), exposure suites & BCD's will have a big impact on weight choice.

Bubble suggest 5-6 pound as starting point, and I agree. enjoy Mexico

 

[Dyno Bill]

Let's see how my memory works, salt water is approximately 64 lds for one cubic foot and fresh water is 62.2 lbs so the tough part is the math. Fresh water/s weight is .971 of what salt water is or salt water is 1.02 times as heavy as fresh water so I guess you would take the 1.02 and multiply the weight used now to get the salt water weight. It doesn't seem like there was a big change between pool weight and ocean weight unless you changed your wetsuit. This stuff was a part of some class I took and of course I did a fair amount of pool to ocean switching in the day.
Bill

 

[fisheater]

Nope. You have to adjust for the TOTAL buoyancy difference between salt and fresh water. You multiply the total weight of the diver + gear + lead.