How many weights do you use?

[donacheson]

scubasean once bubbled...


If you are neutral at 10-15 ft. with a tank that has 500psi, you'll have trouble holding a safety stop with 400 psi....

Seems to me that you'd be better off being neutral (floating horiz at roughly eye level), at the surface,with an empty BC and empty tank...

Folks have recently convinced me that the wetsuit compression will play a role in your scenario, as will the fact that you are neutral with more air in your tank than you might surface with...With less air, you will be lighter and thus possibly unable to stay down...

The weight difference between 400 and 500 psi is about 3 ounces, so it's irrelevant.

There's nothing wrong with weighting yourself to be neutral at the surface instead of 10-15 feet down. However, how do you float horizontally at eye level? <G>

 

[scubasean]

donacheson once bubbled...


how do you float horizontally at eye level? <G>

My bad...heh

Vertically...

And, just to be picky, the point you know I was trying to make is that if you are truly neutral at 500 psi at a given depth with *no* air in your B/C, than *any* less weight (such as less air in your tanks...) will make you positively buoyant at that depth.

So, if you were negative at 500, than if you arrive with less pressure, or breathe it down while at the stop, you won't be able to stay at the stop long without swimming to stay there...

And, your wetsuit, if you have one, will expand slightly above the stop, and you will have nothing to hold you down....*Pop* goes the diver...

 

[orca]

donacheson once bubbled...


One should wear as little as possible - just enough to be neutral at 10 or 15 feet with an empty BC and a near-empty (say 300-500 psi) tank. As for myself, a 240 pounder, that takes about 16 pounds with a 3000 psi Al 80, about 13 pounds with a 3300 psi Al 80., when wearing a minimal wet suit.

Why is there a need to increase 3 pounds of lead when using a 3000 psi oppose to 3300 psi Al 80 tanks? is the 3300 psi tank heavier?

As for myself, I'm not exactly in the lightweight category either, in the 230lbs range...

Since I'm only using 4lbs of weight wearing full 3mm wetsuit, how much additional weights you guys reckon I might have to add if say I change to a 5mm and/or a 7mm wetsuit? I know the drill of how to weight myself properly, but I still need to guesstimate for my first dive the additional weights I have to bring down

 

[chrpai]

orca once bubbled...


Why is there a need to increase 3 pounds of lead when using a 3000 psi oppose to 3300 psi Al 80 tanks? is the 3300 psi tank heavier?

Yes, but because of the tank not the PSI. The Luxfer S80's (3000PSI) are 4.4lbs bouyant when empty and the Luxfer S80N ( 3300PSI ) are neutral when empty. So therefore you need 4 more lbs of lead with the S80 where as you dont with the S80N. (Caveat: theres no free lunch... the S80N weighs 35.4lbs and the S80 weighs 31.4lbs).

 

[orca]

chrpai once bubbled...


Yes, but because of the tank not the PSI. The Luxfer S80's (3000PSI) are 4.4lbs bouyant when empty and the Luxfer S80N ( 3300PSI ) are neutral when empty. So therefore you need 4 more lbs of lead with the S80 where as you dont with the S80N. (Caveat: theres no free lunch... the S80N weighs 35.4lbs and the S80 weighs 31.4lbs).

Thanks for the info!

 

[donacheson]

orca once bubbled...


Why is there a need to increase 3 pounds of lead when using a 3000 psi oppose to 3300 psi Al 80 tanks? is the 3300 psi tank heavier?

As for myself, I'm not exactly in the lightweight category either, in the 230lbs range...

Since I'm only using 4lbs of weight wearing full 3mm wetsuit, how much additional weights you guys reckon I might have to add if say I change to a 5mm and/or a 7mm wetsuit? I know the drill of how to weight myself properly, but I still need to guesstimate for my first dive the additional weights I have to bring down

Luxfer's data shows the 3300 psi Al80's are 4.35 pounds less buoyant than the 3000 psi Al80's - probably because of a greater cylinder wall thickness.

As for your other question, I know lots of empirical ways to answer it, but no theoretical ones. One would think someone would have good rules of thumb, though.

 

[GotAir]

I use 16 lbs of lead. and i dive in a 6.5 mil farmer john suit using only the top half and in fresh water and its still not enough. as my air runs down i start becoming possitive. maybe people use more weights to have more control overall. you can always use your BC to make the adjustment. Mike

 

[E-Boat]

4-5 lb in tropical

 

[phulme]

I weigh about 200 lbs and in a thin suit in the Atlantic off Cuba I was using 6 kg with a a light wetsuit. Water seemed particularly salty in this location.

One day I could dive with 5 kg, but another day i just couldn't get down and had to take the extra 1kg.

In the UK, in a 5mm wetsuit I was using 12kg.

Bottom line, it depends a lot on the water condition and on your body at the time. I guess that's why we're told to always bouyancy check.

 

[kavka]

2 kg for shorty
6 kg 7mm full suit
10 kg 4mm compresed neopren dry with 200g undy
I almost always use 15l steel tank