DSMB Requirements

[MacLir]

Hi all. I am hoping for some clarification from experienced folks regarding required use of DSMBs on Red Sea liveaboards. We are planning a family trip next year for either the North/Wrecks or St Johns routes. Due to experience levels in the group (1 entry level Tech, 2 PADI AOW, 2 PADI OW), we are not considering the BDE route as we consider it beyond our collective skill level.

This will be our first trip to the Red Sea. We have not picked a boat yet. Prior liveaboard/land based diving has been New England US, Carrib., Hawaii and similar. All have boat diving experience well in excess of 30 dives.

I have seen conflicting posts on SB and elsewhere as to whether deployment of a DSMB at depth is required for the above itineraries. I have some experience with DSMB deployment, but only in limited training contexts; the rest of my group has no experience. All of us are, of course, familiar and comfortable with inflating and using SMBs at the surface.

Can anyone advise on what the standard practice/expectation is regarding use of DSMBs on Red Sea liveaboards?

Thanks!

 

[Edward3c]

How to use a SMB and deploy a DSMB are both core skills in BSAC training.

 

[Searcaigh]

We have found that many new open water divers are not unable to be deploy a DSMB safely while neutrally buoyant underwater.

Fixed that for you (bold text my addition)

It certainly describes the vast majority of new OW divers I have witnessed over the past couple of decades here in the UAE. There's a couple of dive shops here that tend to churn out OW divers with poor skills because they offer cheap OW courses, and I'm pretty sure a DSMB deployment underwater is not something that is included.

 

[TheRedBeanPanda]

So just assume the conditions you’ll dive and the LOB will require it, buy one and then train with it in the pool before you go. This approach will make great strides towards eliminating the anxiety of a random skill requirement.

When I say no opportunities to practice beforehand that includes pools
The only way I was able to prepare was watching some online tutorials and getting tips from more experienced divers that I know. Info about the "rigorousness" of the requirement was definitely still helpful to mentally prepare, that's why I posted my experience after getting back for others to see. People ask questions according to their individual needs and circumstances

However, we require the deployment of the DSMB underwater neutrally buoyant multiple times for the advanced course.

That's great that you're including it. My AOW did not, either :/ Who's the "we" in this case - did the shop that you work at add that as a requirement?

I call that the "hurry up and blow up the safety sausage before that jet ski runs you over" skill.

In general, as long as you don't drown performing a skill, you have "mastered" it.

Yikes! In the Red Sea in some spots we actually surfaced one by one and jumped straight into the zodiac to not attract oceanic whitetips while bobbing at the surface. (The only time we actually saw one was actually when everyone was back on the boat, welp.) So no can do without DSMB deployment underwater. For their DMs that's definitely a skill that they have to have actually properly mastered.

Have you started carrying one as has been suggested, whether you think you know how to deploy or not

"Having started" in my case was right during the trip in question where deployment was required. Was not able to dive beforehand and even if I had, I don't see how just clipping it to my BCD and not doing anything with it would have been particularly helpful?

 

[inquis]

When I say no opportunities to practice beforehand that includes pools

Eh, one can learn much by going through the motions in the living room. Particularly, how big of a breath is needed for half full (will be full if deployed from 10m) and how long you really have to replace your reg & purge. (It's usually longer than most people initially think.)

 

[TheRedBeanPanda]

Eh, one can learn much by going through the motions in the living room. Particularly, how big of a breath is needed for half full (will be full if deployed from 10m) and how long you really have to replace your reg & purge. (It's usually longer than most people initially think.)

Yupp, I did try to orally inflate on dry land a couple of times =) My biggest issue though is when to let go when I inflate it with my octo. I tend to let go too early in order to not be dragged up and then it's not full enough. That'll just be a question of trial and error in the water mid- to longterm.

 

[inquis]

I tend to let go too early in order to not be dragged up

If you exhale as you fill, you can remain neutral. If volume is insufficient, get neutral with fuller lungs before starting to fill. (Deploying from deeper is another option.)

 

[TheRedBeanPanda]

If you exhale as you fill, you can remain neutral. If volume is insufficient, get neutral with fuller lungs before starting to fill. (Deploying from deeper is another option.)

Good tip, thanks!

 

[Mod63]

My biggest issue though is when to let go when I inflate it with my octo.

Start practicing using your exhaled gas - less change to bouancy and less chance to snag the octo.

 

[NothingClever]

Oral inflation works a lot better for me than exhausting a regulator into the duckbill. I find it a lot easier to control my buoyancy this way. One technique that works well for me is breaking the overall task down into two steps:

1) Unfurl the DSMB and put just a small breath of air into the DSMB. This creates a knot of air that collects at the highest point (the end of my DSMB) and cleans up my “workspace” without altering my depth. I’m relaxed with my spool and DSMB in one hand (left) without any change in my depth. I can take my time, take one last look around at whatever I need to and then carry on when ideal;

2) Check my depth, check that my trajectory is clear of entanglement hazards, breathe deeply, exhale into my DSMB (leaving enough air in my lungs to purge my reg) and release.

With a few iterations, you’ll find your DSMB at the surface proudly at full volume. If the first few times you get to the surface and it’s only half inflated, not to worry because at least you got a marker deployed before your head acted as your SMB (!!). Make a mental note and determine your adjustment(s) - shoot deeper to maximize Boyle’s law (i.e, shooting at 18m produces a much bigger difference than shooting at 8m), exhale more volume at depth, etc.

I’ve found the duckbill can’t handle the volume of gas from the reg and a lot ends up wasted. Because backgas is precious, that technique is not a good option for me.

Also, the LPI method is great in a pool environment where we’re not on the clock and the pool environment is very forgiving of mistakes. Diddling with my plumbing at depth in the ocean doesn't sound appealing. For me, many times I start ascending right after shooting so inserting another step (using both hands to re-connect my LPI hose) in the process between my spool paying out the necessary amount of line and ratcheting myself up isn’t an optimized process.

Enjoy the journey. You can do this!

 

[TheRedBeanPanda]

Oral inflation works a lot better for me than exhausting a regulator into the duckbill. I find it a lot easier to control my buoyancy this way. One technique that works well for me is breaking the overall task down into two steps:

1) Unfurl the DSMB and put just a small breath of air into the DSMB. This creates a knot of air that collects at the highest point (the end of my DSMB) and cleans up my “workspace” without altering my depth. I’m relaxed with my spool and DSMB in one hand (left) without any change in my depth. I can take my time, take one last look around at whatever I need to and then carry on when ideal;

2) Check my depth, check that my trajectory is clear of entanglement hazards, breathe deeply, exhale into my DSMB (leaving enough air in my lungs to purge my reg) and release.

With a few iterations, you’ll find your DSMB at the surface proudly at full volume. If the first few times you get to the surface and it’s only half inflated, not to worry because at least you got a marker deployed before your head acted as your SMB (!!). Make a mental note and determine your adjustment(s) - shoot deeper to maximize Boyle’s law (i.e, shooting at 18m produces a much bigger difference than shooting at 8m), exhale more volume at depth, etc.

I’ve found the duckbill can’t handle the volume of gas from the reg and a lot ends up wasted. Because backgas is precious, that technique is not a good option for me.

Also, the LPI method is great in a pool environment where we’re not on the clock and the pool environment is very forgiving of mistakes. Diddling with my plumbing at depth in the ocean doesn't sound appealing. For me, many times I start ascending right after shooting so inserting another step (using both hands to re-connect my LPI hose) in the process between my spool paying out the necessary amount of line and ratcheting myself up isn’t an optimized process.

Enjoy the journey. You can do this!

Ah, 1) is a neat little trick, thank you!
The LPI method sounds like you would need more hands than two so it was never on my list of options
Will definitely try and practice both oral and octo inflations. I - without thinking - bought a DSMB that is quite big and I and my lungs are not big, so inflating orally will take me more than one breath, probably even at like 10m. But I'll figure out the best way eventually