How much lead? Bad advice?

[Teamcasa]

I keep seeing threads where people are suggesting differing amounts of lead based on the suit they are wearing, tank(s) and other information. Some bash others for carrying too much lead or brag about requiring very little weight However, without knowing their height, weight and other items they carry, no accurate weight estimate can be made.

For instance; A 150 lb, 6’tall man wearing a 7mm full suit with hood, gloves and boots, AL80 tank and a jacket style BCD may need 12-15 lbs of lead.
The same man, using a stainless BP/W, HP100 tank may only need 7-9 lbs. Then again, A man 6’3”, 275lbs, 7mm full suit, 5mm vest with an integrated hood, gloves and boots, jacket BCD, AL80 tank may need 35+ lbs. Then there are the drysuits people. That’s adds more data to the equation.

So before I would recommend any weight estimates, I try to get all of the pertinent data. If I discuss what I use I try to tell the whole story.
I only bring this up because recently my brother was recently certified but seriously overweighed and his wife could not get certified (on the cruise ship) because she could never get heavy enough. Buoyancy is difficult enough for the new diver and very difficult if given in-accurate help.

Dave

 

[TSandM]

I think on almost every thread where somebody asks about weight, someone points out that weight requirements differ. On the other hand, you can often make some ballpark estimates of what is reasonable for people under certain conditions. I dove with a couple of new divers the other day who were diving drysuits and small steel tanks. When they told me how much weight they were carrying, I KNEW they were overweighted by at least ten pounds, because they were way out on the far end of the bell-shaped curve for weight requirements for normal body habitus divers in dry suits (meaning, they were carrying more than I do ). We took fourteen pounds off one, and ten off the other. I wasn't wrong.

So it is possible to give some useful information, with the caveat that it won't be exact and that everybody needs to do a proper weight check to know what they should be carrying.

 

[deepblueme]

Something else that pertains to amount of weight worn in the students/divers comfort level, but I never see that addressed.

I had a AOW student that swore she needed 38 lbs, we did a bouyancy check w/o gear just mfs and she needed 4 lbs, I knew her wetsuit took 18 lbs to make netural.
So I gave her 28 lbs she swore she would never sink, Well by this time she was relaxed and I told her to exhale and lay on the bottom we were in 4-5 of water and breath for a while w/DM (we were getting ready for a PPB dive).

She was totaly shocked when she did, it turned out she was NOT comfortable with the Inst that did her check out dives.
It was kind of funny the next morning when she was doing her S/R dive with a different Inst. she was back up to 38 lbs, the DM I had her with came and got me And I talked to her for a little while and she dropped back to what I had her weighted at.


I also have had ALOT of new divers say they need more lead than I knew they needed cuz they would take in a big breath befor dumping the BCD.

 

[Teamcasa]

...I dove with a couple of new divers the other day who were diving drysuits and small steel tanks. When they told me how much weight they were carrying, I KNEW they were overweighted by at least ten pounds, because they were way out on the far end of the bell-shaped curve for weight requirements for normal body habitus divers in dry suits (meaning, they were carrying more than I do ). We took fourteen pounds off one, and ten off the other. I wasn't wrong.

So it is possible to give some useful information, with the caveat that it won't be exact and that everybody needs to do a proper weight check to know what they should be carrying.

Exactly. You were with them, so you could properly estimate their weight requirements. That’s much harder to do on-line.

Dave

 

[mikerault]

Ah, but what happened when her tank got down to 500 pounds?

 

[deepblueme]

her 4lbs
wetsuit 18lbs
Al80 @ 500 4-6 lbs

I gave her 28 she was about 1 lb heavy with 700psi

The point of the story was that she wasnt comfortable with her buddy/Inst that made her think/need all that extra weight.

 

[cool_hardware52]

I keep seeing threads where people are suggesting differing amounts of lead based on the suit they are wearing, tank(s) and other information. Some bash others for carrying too much lead or brag about requiring very little weight However, without knowing their height, weight and other items they carry, no accurate weight estimate can be made.

For instance; A 150 lb, 6’tall man wearing a 7mm full suit with hood, gloves and boots, AL80 tank and a jacket style BCD may need 12-15 lbs of lead.
The same man, using a stainless BP/W, HP100 tank may only need 7-9 lbs. Then again, A man 6’3”, 275lbs, 7mm full suit, 5mm vest with an integrated hood, gloves and boots, jacket BCD, AL80 tank may need 35+ lbs. Then there are the drysuits people. That’s adds more data to the equation.

So before I would recommend any weight estimates, I try to get all of the pertinent data. If I discuss what I use I try to tell the whole story.
I only bring this up because recently my brother was recently certified but seriously overweighed and his wife could not get certified (on the cruise ship) because she could never get heavy enough. Buoyancy is difficult enough for the new diver and very difficult if given in-accurate help.

Dave

Dave, I agree that "off the cuff" extimates of required lead without investigating all the part of the puzzle are no real help.

As a starting point I assume the diver is close to neutral in just a swimsuit, most people are, and for those who aren't we can adjust later.

Now just add up the positively buoyant items like wetsuit, Jacket BC and buoyant tanks. That will provide a good starting point for estimating total required ballast.

Lets say we have 7 mm west suit that's +20 lbs, and an AL 80 that's +4 empty and a Jacket BC that's perhaps +3 That's a total of 27 lbs of positive buoyancy.

If the diver is a "floater" then add a couple, if they are a "sinker" take a way a couple.

Nothing beats a real live in water buoyancy check, but if you know the buoyancy of the exposure suit you can atleast start in the right ballpark.

Working out these numbers is also a very good way to demonstrate to new divers that they really don't need 40 lbs of lead, but they do need to stop finning if they want to descend.


Tobin

 

[SteveFass]

I don't see what the fuss is all about. Lead is cheap, and if you are traveling, it is usually free! When I hear free, I treat it like an all you can eat buffet - I stuff my pockets with all I can fit!

:sofa:

 

[spectrum]

I agree with the OP and it's a pet peeve of mine.

No reference to dive weight can have any credibility without the facts especially fresh or salt, cylinder used, specific suit and ancillary gear carried.

Even with those facts individual body make-up, age of the suit and a host of other little variables conspire to make one divers weight useless to another.

While some of the weights some divers cite do seem high I have learned from diving with some such divers that at least at the time that is what they needed. As they gain experience, relax and begin to carry less air in their lungs and as their suits loose that factory fresh buoyancy thinks will change. I would rather see a new diver be 5 pounds overweight than 2 pounds under. Of course overall I'd like them to be just right.

Pete

 

[O.M.O.H.]

I see many provided +18 to 20lbs of buoyancy for a 7mm suit, sound just about right...
I am about to switch to a drysuit. What is your buoyancy estimation of a "bag" suit with a 16oz undergarment? (I know we will redo my weighting with the instructor but just for the kicks i wonder what my lead requirement will be). I normally wear 32lbs with a 7mm Tylos suit and aluminum 80 tank in seawater. I am 6’ and 225lbs.
Thanks