YD Scuba Diving Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
Imported post

Having recently acquired a twinset 7ltr @ 300bar, does anyone know the ideal weight/lead/shot I would have to carry in order to offset the gas lost at the end of the dive?

I weigh 16.5stone and would dive with a membrane dry suit and thermal under garment. Obviously i have tried weighting in the pool already but it is not indicative of open water use.

All i want to know is that i have enough weight to prevent a runaway ascent.

can anyone help?
 

·
Registered
Joined
·
676 Posts
Imported post

<font color='#810541'>You need to do a buoyancy check!

Cylinders almost empty and you want to be neutrally buoyant at say 3 metres ideally. In fresh water with no added weight with 25 bar in twin 12's I am still slightly negative.

There is no formula, get out there and experiment, that's what quarries are for.
 

·
Registered
Joined
·
1,966 Posts
Imported post

<font color='#0000FF'>YEP you have to play
I use 300 bar 12's and you end up starting the dive quite negative just to make sure you are able to stay down on empty tanks.
but remember 300 bar cylinders are quite negative in there own right anyway
wax
 

·
Not as tall in real life
Joined
·
4,059 Posts
Imported post

[b said:
Quote[/b] (sausagedog @ Nov. 18 2003,18:41)]I weigh 16.5stone and would dive with a membrane dry suit and thermal under garment. Obviously i have tried weighting in the pool already but it is not indicative of open water use.
If you tried it in the pool with all your normal kit on then it should give you a reasonable indication for fresh water.

On your previous setup, (Was it a single 12?) What was the difference in weight between fresh and salt water.

Daz
 

·
A short fat well off crap cave diver. Likes wrecks
Joined
·
15,343 Posts
Imported post

300bar tanks tend to go from very negitave empty to seriously negitave full
 As a result you would have to compleatly review your weighting for 300bar tanks.

ATB

Mark Chase
 

·
Senior Member
Joined
·
1,773 Posts
Imported post

<font color='#000F22'>I've got 300 bar 7s and with a SS backplate, membrane, weasel I use 3kgs in the sea. I'm over-weighted but I'm still getting used to them. Also it'll do for when i load the extra warm stuff on this winter.

232 12s I use 3kgs or sometimes 2kgs in the sea and no weight in fresh. I use Ali stages and and ali argon bottle.

Go for a little dive in shallow water and get out before you get to 80-100 bar.

Bleed the tanks down to 30/40 bar and do a buoyancy check.
 
1 - 7 of 7 Posts
Top