Using a closed-bottom DSMB/Lift Bag

[inquis]

It's more about thinking through how to actually use this thing without a wild ride up

Stay horizontal for greater resistance to acceleration. Commit to jamming the inflator hose on, exhale hard to help offset the buoyancy increase, and let go after a sufficient # of mississippis (depth dependent as stated above). You don't have time to "inspect for fullness".

 

[DiveLikeAMuppet]

Some of them maybe. The one I have has something >50# lift. It's about 6ft long and has a circumference of about 16-1/2 inches. Their current issue that's the similar or the same as mine is spec'd to have 52# lift
Not all that much, I suppose for doing serious salvage work, but it seems like a lot when I'm trying to fill it up before letting go

Oh Halcyon finally made a proper DSMB, I didn’t know You definitely are not deploying that from the shallows with enough gas unless you hold onto something. 20-25 meters will be OK if you can use an inflator. What I would do is put a small squirt of gas in, let it unroll and check that it’s clear and fill about 1/3 with with inflator and quickly let it go, it’s a lot of lift to manage.

 

[Edward3c]

ha ha, yeah I suppose I knew that. Guess I worded my question poorly...(english is hard for an engineer, after all..)

It's more about thinking through how to actually use this thing without a wild ride up...or if it even can be used from a shallow depth

The only way you're going to get a fully inflated DSMB it to secure it to the bottom, inflate then let it go.

When I let mine go from 6m I'll normally complete the fil at the surface, if I need to.

 

[bradlw]

and let go after a sufficient # of mississippis

In practice, about how many Mississippi's do you think it takes?
I'm going to play with it some more the next time I get back into the water with the right conditions...

Oh Halcyon finally made a proper DSMB, I didn’t know

I think they've had it since "the beginning" (well I don't really know when the beginning for them was, but still).....I bought mine around about 24-25 years ago when I bought my single-tank BP/Wing set-up. Pretty sure it was the only one they sold back then.(??) I want to say they had some bigger lift bags, but as a marker I remember it as being the only one. Long time ago so I'm probably wrong.....