Lift Bags, a simple question

[Gary K]

I was thinking of getting an AP valves lifting bag at this weekends diveshow, not for anything specific but just in case. So, as normal, I'm looking in advance for the specifications. The 25kg bag is enough, but they do 3 models:

A. open
B. with dump valve
C. sealed with pull dump valve

Now I understand A and C as they are just like the SMB's but how does B work? Surely if it was open style with a dump valve, wouldn't the air just come out of the open bottom anyway? Am I missing something?

As a guide A=£19 B=£27 C=£37

many thanks in advance

[turbanator]

With 'B', the dump valve may be so that you can control the ascent with a load that is less than the lift bag's capacity.

[Andy the Coastie]

Originally Posted by warmwaterdiver

I was thinking of getting an AP valves lifting bag at this weekends diveshow, not for anything specific but just in case. So, as normal, I'm looking in advance for the specifications. The 25kg bag is enough, but they do 3 models:

A. open
B. with dump valve
C. sealed with pull dump valve

Now I understand A and C as they are just like the SMB's but how does B work? Surely if it was open style with a dump valve, wouldn't the air just come out of the open bottom anyway? Am I missing something?

As a guide A=£19 B=£27 C=£37

many thanks in advance

A 25 kg is the same lift as a DSMB......

Why not get a 65 kg'er ........ ?

[Conor]

No expert, but feel like babbling

With an SMB you shoot it off and you want it to reach the surface, thats its only purpose.

With a lft bag, you may want to lift something or just move it. And unless the weight of the object is exactly the same as the displacement of the bag then there will be a need to control the air in the bag so that you can either put it down again or so that you can control its ascent.

Imagine having divers overhead and wanting to lift a 15kg object with a 25kg bag. You would want to put in 15L until it is weightless and then as you guide it to the surface, be able to dump the air (like the BC) to keep the displacement at 15kgish

Does this make sense?

Conor

[Deck Bitch]

good thing would be to buy cheap but good make but buy two. when u get that port hole ucan make sure it ends up at the top of the sea. allways use two bags on the things u like. if it sinks u will cry, may be noton outside but inside! & no 1 two blame but urself, bean there got the tshirt !!!!P.S don't forget to buy some decent stainless steel clips.

[Gary K]

Originally Posted by Andy the Commie

A 25 kg is the same lift as a DSMB......

Why not get a 65 kg'er ........ ?

I could do but was thinking if its only a bag of scallops, the odd bit of spidge, etc, 25kg is prob enough, plus the 65 is going to be bigger to carry folded up also

65kg style A=£23 B=£34 C=£43

so not a lot in it 25 vs 65, just the different styles, as per usual, style C is preferred as its the most expensive

[turbanator]

Originally Posted by warmwaterdiver

I could do but was thinking if its only a bag of scallops, the odd bit of spidge, etc, 25kg is prob enough, plus the 65 is going to be bigger to carry folded up also

65kg style A=£23 B=£34 C=£43

so not a lot in it 25 vs 65, just the different styles, as per usual, style C is preferred as its the most expensive

Well you need to control the ascent then or you'll bend the scallops, don't forget they're sat divers.

What Connor said, also, there is the rare occasion (very rare for us recreational divers) that you would want to move a load horizontally, e.g. removing something heavy from inside a wreck.

r
P

[Juz]

Originally Posted by Andy the Commie

A 25 kg is the same lift as a DSMB......

Why not get a 65 kg'er ........ ?

Standard AP DSMB's are 11kg.

You want version C.

Juz

[Andy the Coastie]

Originally Posted by Deck Bitch

good thing would be to buy cheap but good make but buy two. when u get that port hole ucan make sure it ends up at the top of the sea. allways use two bags on the things u like. if it sinks u will cry, may be noton outside but inside! & no 1 two blame but urself, bean there got the tshirt !!!!P.S don't forget to buy some decent stainless steel clips.

:FU2

[Conor]

Is it normal enough to use a suitable lift bag as/instead of a back up SMB?