I need your help. DSMBs, what are people's questions/concerns/etc.?

[SlugLife]

edit: removed off topic

I mean if you plan on surviving a rebreather malfunction you are basically carrying all the gas you would on oc and a rebreather.

I actually have 2 25kg lift bags stuffed between the padding and my plate just in case i completely flood my Pathfinder and my bcd breaks, gives me enough lift not to have to leave the baby on the bottom.

I've thought about putting a lift-bag in a similar location. I rarely need a lift-bag, but usually when I do, it's finding some random treasure like a high quality anchor.

 

[wetb4igetinthewater]

It depends on the type of dive. If your dive-profile looks like this, and is in open-water....

\                            /
 \                   /------/
  \                 /
   \      ^        /
    \----/ \------/

Your backup gas only needs to be enough to safely surface. ex:

\               /
 \        /----/
  \      /
   \    /
    \--/

For cave though, you're generally correct.


I've thought about putting a lift-bag in a similar location. I rarely need a lift-bag, but usually when I do, it's finding some random treasure like a high quality anchor.

@grantctobin, @Vicko, @SlugMug and anyone else, can we start a DM thread regarding rebreathers and stop discussing it in this thread in the basic forum?

Thank you all.

 

[wetb4igetinthewater]

If I hadn't been reading the thread, this pic would make a good guessing-game.

Ideally, your DSMB doesn't need much gas to get you neutral, and therefore no gas is back there. However that's not always possible if one is overweighted, or something like a flooded drysuit.


I think this is the right approach 90% of the time. The other 15%, lets say you're in an overhead environment (which I have heard of a BCD failing in a cave before), then using a DSMB as a BCD of sorts makes a little more sense. When you get back to open water, it might make more sense to switch back and go the climbing-rope option. It may also be necessary if someone doesn't have a long enough spool.

In other words, it's useful to describe both, even if you point out that one option is usually more practical.

Let's not discuss cave diving here, as this is the basic forum and I'm targeting open water divers with this document. If we start getting into cave diving, then we will have to get into things like cave snorkels.

Divers are just at the end of their diving, heading to the surface, and need to notify the dive boat to pick them up. That's the scenario I'm focusing on.

 

[BlueTrin]

One thing I struggled with is when I got a reel there wasn’t a very good guide for deploying with a ratchet reel and avoiding catching the reel lever with line when deploying

 

[SubseaSports]

One thing I struggled with is when I got a reel there wasn’t a very good guide for deploying with a ratchet reel and avoiding catching the reel lever with line when deploying

You probably figured it out by now, but leave little to no line between the marker and reel. Let it hang when unfurling if necessary.
I have mine stowed on the backside of the reel and connected to the reel....ready to deploy. I send it early when I have made decision to ascend. I typically use a dedicated QD hose to inflate as it fast and I am virtually guaranteed a full marker at the surface. This may fall into 'other methods of inflation'.
If I am pulling a flag, I have the smb on a spool....ready to deploy.

To the OP...if you are going to put together an actual manual..I would suggest using a traditional format.
Begin with the 'why use one'...'methods' and 'how to exit' with one.

I worked in a soflo shop that had a boat as well. In house trained divers were sufficiently trained in deploying one. However the vast majority of out of towners did not have a clue. As in 'ok..you need tanks...yup, do you have an smb..huh?'
I think a document is worthwhile, but how would you 'deploy' it to make a difference?

 

[wetb4igetinthewater]

think a document is worthwhile, but how would you 'deploy' it to make a difference?

Do you mean distribution? My best bet is a blog post for SDI, like I did for my neutral buoyancy/trim series.

 

[RobPNW]

I'm curious if people can speak to advantages and disadvantages of using a small reel or a spool, assuming they both have the same length of line. Thanks. Seems the small spool would take up a little more space as gear but would be easier to work with.

 

[inquis]

A spool is nearly impossible to tangle/jam, occupies less space in the pocket, slower to reel up unless practiced, and typically has a smaller capacity. For most NDL deployments on drift dives, a spool seems more common. If going for an extend drag, a reel works well due to the handle. Try both, see which you prefer.

 

[SlugLife]

I'm curious if people can speak to advantages and disadvantages of using a small reel or a spool, assuming they both have the same length of line. Thanks. Seems the small spool would take up a little more space as gear but would be easier to work with.

PiranhaDiveMfg has some very affordable reels, if you want to give one a try. Standard disclaimer that "you get what you pay for," but I'd say zero meaningful complaints for the $15 reel I got. I took mine apart added some silicone grease, and put it back together.

Reels Piranha Dive Shop |

www.piranhadivemfg.com

A spool is nearly impossible to tangle/jam, occupies less space in the pocket, slower to reel up unless practiced, and typically has a smaller capacity. For most NDL deployments on drift dives, a spool seems more common. If going for an extend drag, a reel works well due to the handle. Try both, see which you prefer.

I probably did something wrong, but I have had a spool come undone in my pouch and become tangled. Not often, but it happened once.

 

[Blackcrusader]

I believe the idea is that a controlled ascent with a DSMB as BC would be difficult. you would have to vent air on the way up, and if you ever overshot on venting, add air. If the DSMB is full on the surface, you have complete control of your ascent rate while reeling yourself up.

Actually not difficult. Clip DSMB to D ring and you can use the purge valve to release air if you need. You do not need to shoot the DSMB to surface if deploying it for controlled buoyancy lift in case of failure of BCD. My DSMB does create a lot of lift I have used it as a lift bag for heavy objects on cleanup dives. So do not over inflate at depth, enough air to get it to unfurl. A slow ascent speed it easy to maintain.