Question Floppy DSMB

[DiveLikeAMuppet]

My DSMB is a bit floppy compared to DSMBs of other divers. I would like it to stay rigid inflated even after very long dives. Looking for ideas.

I’m using Dirzone 180cm DSMB, closed bottom. It’s not deflated but it loses maybe 10-15% of volume.

• There is enough gas, if anything too much (I might deploy 1/3 full DSMB from 50 meters).
• I’m generally not pulling myself up on the DSMB or hanging under the DSMB (definitely not compared to many other divers who don’t suffer from floppy DSMBs).

My thoughts:

• Leaks?
• OPV is too tight or not tight enough? OPV position is quite high - maybe that forces some gas out?
• Inflator nipple leak?
• I should try different DSMB brand?
• I’m a moron and pull too much?

 

[johndiver999]

put soapy water on it and find where the leaks are. I often get tiny puncture wounds on mine.

 

[NothingClever]

Definitely got a leak. Either the OPV or a pinhole somewhere. If shooting from 50m, that thing should be properly taut.

 

[rmorgan]

• There is enough gas, if anything too much (I might deploy 1/3 full DSMB from 50 meters).

50 meters?

 

[DiveLikeAMuppet]

50 meters?

164 feet if that helps?

 

[Rich1280]

The inflator nipple springs get salty and leak slightly if you don't rinse them well. I'd check that as part of the leak check. I did find them fore sale online a while ago, about a fiver apiece. I think I put a link in a thread on here somewhere.
my older halcyon ones leak through the valves as well, it's not a brand thing.

Rich

 

[NW Dive Dawg]

Talk to your DSMB and tell it to think about baseball once inflated.

 

[rmorgan]

164 feet if that helps?

Thanks. I know the conversion factor, of course, but (recreational diver that I am) had no idea under what circumstances one would deploy a DSMB at 160'. Teachable moment, please?

 

[DiveLikeAMuppet]

Thanks. I know the conversion factor, of course, but (recreational diver that I am) had no idea under what circumstances one would deploy a DSMB at 160'. Teachable moment, please?

Wreck diving in tidal areas. The skipper drops a shot (a rope with something heavy) on the wreck when it's slack water so that you can descend and actually find the wreck in poor visibility. You swim around, when it's time to ascend, you put up a DSMB from the bottom and start drifting.

The benefit if is that when the skipper sees e.g. 10 DMSBs, they will pull the shot, let the boat drift together with all the divers to later pick everyone up and don't need to return back to the dive site. Deco under a DSMB is also a bit nicer than hanging onto a rope in current.

The problem is that you might drift for quite a long time and spread out, so a DSMB that is just lying on the water will not be visible from distance.

I used 50m just to avoid funny comments about not putting enough gas when inflating the DSMB but it's the same protocol for shallower dives too.

Definitely got a leak. Either the OPV or a pinhole somewhere. If shooting from 50m, that thing should be properly taut.

I think it's the OPV. No pinhole leaks - no bubbles when I sprayed the whole thing with a detergent - but the OPV will release some gas when I bend the DSMB.

 

[Johnoly]

but the OPV will release some gas when I bend the DSMB.

Different OPV's are made from various materials.. If you take it apart, use a household magnet to test the metal spring material and see if it's magnetic. A good quality metal spring will be made of stainless steel and not magnetic. It's a pretty quick & simple test to do. You can also check the inflation spring on it too.