DSMB Technique

[steinbil]

I agree entirely. And if you press GENTLY the purge button, the resulting airflow will be the same or even lower than when you are breathing, so the risk of freezing is minimised. No one forces you to press fully the purge button for filling the buoy in 0.1s...

Exactly, you don't want major buoyancy changes to happen fast anyways, especially when handling bigger lift bags. You could even adjust the reg to reduce flow.

 

[Klopo]

I unroll the buoy, fill it with a little air so that it stands vertically. Then I let out very little air so that I become slightly negative. Then I fill the buoy with the free 2nd stage as soon as the pull is in the line, exhale and let the buoy go.

 

[blueskies_up_ahead]

You all seem keen on helping lol, but I wasn't looking for advice I have zero issue with the way I do it (and have been taught). The only change I will make is learning to inflate orally. At that point I may switch to a closed DSMB. I may try the drysuit inflator for fun, but prefer a method that works no matter which setup / suit I use.

 

[BlueTrin]

You all seem keen on helping lol, but I wasn't looking for advice I have zero issue with the way I do it (and have been taught). The only change I will make is learning to inflate orally. At that point I may switch to a closed DSMB. I may try the drysuit inflator for fun, but prefer a method that works no matter which setup / suit I use.

If you are dead set on not using a quick disconnect inflator, you can dump a bit of air when you breathe in.

At some point the lift from your bag will be more than how negative you are since that you should not be much more negative than the amount of air you used from your cylinders. (Unless you carry negative ditchable equipment)

If you still want to inflate more, you can kick a bit down while doing it to inflate longer. If you do this, you better make sure you don’t catch anything when you inflate/release it while kicking down and it’s better you practice this one before to try it for real.

A 6 footer won’t be full if inflated at such a shallow depth, and the very wide 6 footers won’t be full from oral inflation unless you put many many breaths at a reasonable depth.

You use one a bit less than 5ft but don’t know how wide it is. Depends of the conditions you dive I guess and how important it is for you to be seen where you dive.

 

[Wibble]

If you are dead set on not using a quick disconnect inflator, you can dump a bit of air when you breathe in.

At some point the lift from your bag will be more than how negative you are since that you should not be much more negative than the amount of air you used from your cylinders. (Unless you carry negative ditchable equipment)

If you still want to inflate more, you can kick a bit down while doing it to inflate longer. If you do this, you better make sure you don’t catch anything when you inflate/release it while kicking down and it’s better you practice this one before to try it for real.

A 6 footer won’t be full if inflated at such a shallow depth, and the very wide 6 footers won’t be full from oral inflation unless you put many many breaths at a reasonable depth.

You use one a bit less than 5ft but don’t know how wide it is. Depends of the conditions you dive I guess and how important it is for you to be seen where you dive.

Hence most training SMBs are tiny little skinny 1m/3ft things that inflate with one breath.
And therefore are useless in the sea***.

The only SMB in the sea is one that can be seen a way off. Big is best. Girth matters.


*** The only exception would be sending up a 'message' SMB which, by convention, is yellow. The boat would see two bags sticking up in a 'V' and would throw down the emergency oxygen if agreed in advance.

 

[cavemania]

Here is an excellent resource, I highly recommend everyone to watch it.

 

[Edward3c]

Here is an excellent resource, I highly recommend everyone to watch it.

Totally impractical when the DSMB is to be deployed from a wreck at +30m. A 2m DSMB is needed to be seen in most U.K. locations because of wave and swell conditions. Once deployed it not possible to pull it back down.

 

[ABay Diver]

You might start with a DSMB of 44 to 48 inches. I prefer the close bottom type with an OP valve. I can usually get enough air in it with one breath from 20 feet. I also use a Y fitting sometimes to inflate from my BC LP hose, especially the jumbo DSMBs:





The DSMB should have a non-locking inflator:



I stick it in the fitting, psssst, zoom, up, up and away.

Unfortunately, I have not seen those fittings in years though there are some that are reverse of it that would likely work as well or better.

Where do you get those Y inflators? Never seen one before and i like that better than using a second inflator hose.

 

[rongoodman]

Where do you get those Y inflators? Never seen one before and i like that better than using a second inflator hose.

I wouldn’t want the DSMB that close to my body while filling it from an LP hose.

 

[ABay Diver]

I wouldn’t want the DSMB that close to my body while filling it from an LP hose.

I currently use a second hose that extends about an inch beyond the bcd dump valve button and for me closeness is not an issue at all. Its quick, you don’t have to remove your reg from your mouth, disconnect and reconnect your bcd inflator hose, fiddle with your octo and reconnect that. Ive tried all four: oral inflate, octo inflate, bcd disconnect/reconnect; second hose lpi, and second hose lpi is quicker and easier by far but your mileage may vary.