At what depth to deploy DSMB

[TSandM]

The important question is not where we deploy, it's HOW we do it so that we don't lose buoyancy control.

If you are using a small (3'/1m) bag, you can put a full breath in the bag safely by simply tilting a small amount head down and finning gently downward while you are filling the bag. Larger bags require faster movement or assistance, and are much easier if you shoot them very deep (note that a bag shot at 60' only has to be 1/3 full to be full at the surface).

I do my ascents by going 60 fpm to half my maximal (or average) depth. I shoot the bag at the first stop, which is usually in the 40 to 50 foot range.

 

[Sas]

I deploy it at 15m usually. The important thing is that you deploy it shallower than the line you have on your spool/reel. My buddy has hilarious footage of me deploying an SMB at 21m when it had 17m of line on it recently... I forgot I'd shortened that spool!

 

[Sir Dive Alot]

I deploy during or after my safety stop, I've seen a couple people deploy deeper and get entangled. I use it to let the boat know where I am if i get split from the buoy line or in rough seas.

 

[BKP]

Has anyone tried this, in order to mitigate buoyancy issues while ascending with a deployed SMB, and reeling the line at the same time?
Most SMBs have approx. a 30# lift or greater. So, if you deploy from a safety stop, or deeper, you can completely deflate your wing, wind yourself up the line, then re-inflate on the surface. I've never tried it, but it would seem to save having to think about venting during the ascent, while you're dealing with the spool, and also winds the line up on the way.
Might be a foolish idea... just a thought...

 

[hawkenph]

Has anyone tried this, in order to mitigate buoyancy issues while ascending with a deployed SMB, and reeling the line at the same time?
Most SMBs have approx. a 30# lift or greater. So, if you deploy from a safety stop, or deeper, you can completely deflate your wing, wind yourself up the line, then re-inflate on the surface. I've never tried it, but it would seem to save having to think about venting during the ascent, while you're dealing with the spool, and also winds the line up on the way.
Might be a foolish idea... just a thought...

Hi,
That's what me and my Dive Buddy do. Just completely deflate our BCD's and start winding the line as we ascent and once we are on the surface re-inflate our BCD's.
Kurt in Cebu

 

[rcs9250]

One of the most important things you MUST do is keep your head up and looking horizontally. If you end up looking down for a period of time it's over. Also, many folks have a habit of inhaling and then holding that breath while doing a task. That also ends your hover and away you go.
If you need to be looking at your task , which you do, do your task at eye level. Keep an eye on your depth gauge too. Another very hand way of seeing if you are ascending or descending is to look at the particulate in the water. There's always particulate. If the particulate is stationary, so are you . If the particulate looks like it's going down, you are going up. If the particulate looks like it's going up, you are going down.
Photographers are usuall a little better at the stationary position because they are focusing on a specific object at the depth they are at and will very consciously work there breathing to hold the depth. It takes practice too though.
Practice, practice, practice. Everyone more or less goes through what you are going through initially.
There are some excellent 5th D videos on youtube that will show the skill. Watch them very very carefulyy. Watch the divers position, speed , head position, height of hands , breathing , etc., etc., etc..

Dive safe.

 

[TSandM]

Not only is it serious "cheating" to go negative and hang on the bag (read: makes depth control on ascent ridiculously easy), but it also has the nice effect of causing the bag to stand UP on the surface, so that it is more easily seen from the boat. Note that this also requires that you weight yourself so you can be a little negative during whatever shallow stops you do!

 

[DevonDiver]

Has anyone tried this, in order to mitigate buoyancy issues while ascending with a deployed SMB, and reeling the line at the same time?
Most SMBs have approx. a 30# lift or greater. So, if you deploy from a safety stop, or deeper, you can completely deflate your wing, wind yourself up the line, then re-inflate on the surface. I've never tried it, but it would seem to save having to think about venting during the ascent, while you're dealing with the spool, and also winds the line up on the way.
Might be a foolish idea... just a thought...

What would you gain? The 'lazy factor' of not having to maintain neutral buoyancy during your ascent?

What if something happened to your DSMB? It can burst. The line can break. It can get swept into surface obstructions...

What if you had to release the line to deal with an emergency underwater? You'd look pretty ineffective if another diver got into difficulties and you couldn't get to them quickly because you were hung from a line like a flacid pendulum...

Being a little 'negative' to help your bag stand up is one thing. Dumping the entire contents of your BCD is another...

As a 'rule-of-thumb', I would recommend that you weren't more negative that your breath control could compensate for (plus, maybe a tiny squirt with the LPI, if you really need to)..

 

[TSandM]

DevonDiver, you have some good points . . . but it's important to remember that, in single-tank recreational diving, most people will START the dive only five or six pounds negative, and will be significantly less negative than that at the end. Of course, with thick neoprene, they'll be much more negative deep, but if we are talking about deploying a bag in the "half maximal depth" range, we're up where much of that buoyancy has been reacquired. So I don't think one has to worry about someone hanging on the bag suddenly plummeting to the depths if the string breaks

 

[BKP]

What would you gain? The 'lazy factor' of not having to maintain neutral buoyancy during your ascent?

What if something happened to your DSMB? It can burst. The line can break. It can get swept into surface obstructions...

What if you had to release the line to deal with an emergency underwater? You'd look pretty ineffective if another diver got into difficulties and you couldn't get to them quickly because you were hung from a line like a flacid pendulum...

Being a little 'negative' to help your bag stand up is one thing. Dumping the entire contents of your BCD is another...

As a 'rule-of-thumb', I would recommend that you weren't more negative that your breath control could compensate for (plus, maybe a tiny squirt with the LPI, if you really need to)..

I wouldn't consider it "lazy factor" if it's actually going to serve a purpose, such as standing up the bag, or freeing your hands to work the spool on the way up.

Additionally, if you used breath control (which, of course, is proper buoyancy control during a dive), that presumes you've left air in the BC, which expands on ascent, and defeats the purpose of an empty wing, if you're going to cork.

Finally, having an issue with the bag (burst smb, broken line, etc.), and having to aid another diver, it's a simple matter of dropping the spool, and finning up and over (while inflating). Probably much simpler than working the spool, while adjusting your BC buoyancy on ascent. I'm not talking about narcosis level depths... rather approximately 50ft. on up...

Viable or not, I plan on trying it next dive just to satisfy my personal overly stubborn perspective...