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!

 

[wetb4igetinthewater]

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.

That's a unique restraint for exiting the water. I assume the DM deploys the DSMB and sends people up 1 at a time then. Is that correct?

I would expect most DMs throughout the world that have to deploy DSMBs to be proficient at it. When I taught OW in the confined water sessions, I would first have students inflate at the surface a small DSMB, then at depth while neutrally buoyant as close to the bottom as possible. We would discuss the depth necessary to inflate fully using Boyle's Law. In the open water dives, then it would be a more useful DSMB. At that point, I hadn't read the tip someone posted here for marking the DSMB for different depths. So 33'/10m would be at the halfway mark (from the bottom). 66'/20m a third from the bottom. 100'/30m a fourth from the bottom. So on exhale, you see before you release if the DSMB is going to be fully inflated. Now I always taught to inflate with one big breath to avoid becoming more buoyant when trying a second time. While we didn't do this in class, my students were taught to experiment with what depth they needed to be to get their DSMB fully inflated. They may not be able to fill it halfway at 33'/10m, but always (in my limited experience) they were always able to at least one-third from 60'/18m.

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

Garry Dallas of RAID has a nice video on YouTube here at about the 1:13 mark.
I'm sure you'll dial it in quickly.

 

[rongoodman]

If I'm someplace where I might need to inflate an SMB big enough to be seen, such as out at Cocos Island, I have an extra, longish, LP hose clipped off to my left waist D-ring. Works like a charm and I have plenty of room to keep everything away from my body.

 

[TheRedBeanPanda]

That's a unique restraint for exiting the water. I assume the DM deploys the DSMB and sends people up 1 at a time then. Is that correct?

Yes, exactly. We would gather for the safety stop, the DM sent the DSMB up and when the first people were done (or those who were lowest on air) he would point at us one by one and we'd go up to the zodiac. Sometimes this also involved hanging around a bit longer at the safety stop until the boat arrived. But always underwater, at least at 5m depth. Those were sites such as Deadalus or Elphinstone where bobbing around on the surface for too long could attract unwanted playmates. When this happened first, we were not actually properly briefed for it so it was a bit confusing

Marking the DSMB also sounds like a good lifehack, thanks!

 

[Searcaigh]

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.

I retain an LP hose for drysuit diving and use that to inflate my DSMB

+1 on adding a small quantity of air at the beginning, especially if you are also using a large camera rig, you need to avoid any line entanglement and a slightly buoyant DSMB helps in this regard.

 

[divezonescuba]

If you don't teach your open water course properly weighted (including weight distribution) and neutrally buoyant/trimmed, I'm not surprised.

I am not sure why you think that.

A number of years ago, we switched to plate and wings so that we could better weight and trim students. They are significantly more expensive than jacket BCD, but we think that they enable divers to become more proficient.

We will always error on the side of safety when it comes to weighting. It is better to be a pound or two over-weighted than underweighted if that is what the weight combination require.

I have yet to inherit an advanced open water student, who took open water from another instructor who could perfectly deploy a DSMB while neutrally buoyant. Most of the ones that I have encountered don't even own a DSMB. In fact, we require all of our AOW students to have their own DSMB, so that they can obtain the necessary proficiency to deploy it safely.

 

[Whistler]

Garry Dallas of RAID has a nice video on YouTube here at about the 1:13 mark.

Much respect for the trim in this video.

 

[stepfen]

Much respect for the trim in this video.

Indeed, quite impressive.

BTW any ideas what is the source of the small bubbles stream? It could be a leaking first stage / tank valve o-ring, but it appears too far on the side and occasionally it appears on both sides of his face which I can't explain. Any ideas?

 

[inquis]

any ideas what is the source of the small bubbles stream?

In one of the comments he said, "had a tiny split in the mask seal, unaffected by it and didn’t notice it until afterwards."

 

[stepfen]

In one of the comments he said, "had a tiny split in the mask seal, unaffected by it and didn’t notice it until afterwards."

Interesting, but I don't think so. If there was a split, water would also be getting in and, in that rate, mask would flood quite fast. His mask remains clear throughout. And having a split on both sides? Something else is probably going on here.

 

[Antonios (Holy Diver)]

Interesting, but I don't think so. If there was a split, water would also be getting in and, in that rate, mask would flood quite fast. His mask remains clear throughout. And having a split on both sides? Something else is probably going on here.

Maybe he is just exhaling. I have heard of another very experienced instructor and cave diver, George Vandoros, who often seems like doing exactly the same thing - constantly exhaling a small stream of bubbles. You may see him doing that at the following video, at 4.01-4.03 (the bearded diver with the orange-sleeved drysuit).