SMB Depth Questions

[conallmeehan44]

Hello everyone, I have a decline fully closed(can only inflate orally) DSMB. I think this is good for deploying form shallow water before or during my safety stop with a spool. My question is, if I was going on a wreck dive with strong current where I would need to deploy my DSMB at say 30m so the boat can follow me, would the decline DSMB be hard to inflate and the spool might not have enough line. So I would probably have to get a reel and what type of DSMB do you recommend?

 

[Boarderguy]

Edited:
Yours has the ability to inflate via an LP hose but not your 2nd stage. It also has an OPV (over pressure valve) to prevent it bursting at it ascends and expands. No need to orally inflate unless you're OOA and at the surface.

I use this one and it works great.

DGX Gears Yellow/Orange Combo Surface Marking Tube { 6 ft | 1.8 m }

DGX Yellow/Orange Combo Surface Marking Tube - One Side Orange, One Side Yellow { 6 ft | 1.8 m }

www.divegearexpress.com

 

[conallmeehan44]

You have an SMB, not a DSMB. It is designed to be inflated at the surface or very shallow. With no ability to inflate via an LP hose or 2nd stage it would take quite a few good breaths to fill, all while trying to stay at depth with the SMB trying to take you to the surface. The other issue is if you successfully inflate it at depth, you now run into the issue of it potentially bursting since it does not have an over pressure valve.

Do yourself a favor and buy a proper DSMB. I've used an SMB in the past and they suck for anything other than inflating at the surface.

DGX Gears Yellow/Orange Combo Surface Marking Tube { 6 ft | 1.8 m }

DGX Yellow/Orange Combo Surface Marking Tube - One Side Orange, One Side Yellow { 6 ft | 1.8 m }

www.divegearexpress.com

This is what I have: Tecline Closed Buoy with D-ring 117cm Scuba Tech Diving Buy and Sales in Gidive Store

 

[inquis]

You have an SMB, not a DSMB.

"Fully closed" is not synonymous with SMB. Assuming OP meant Tecline when they wrote "decline", their catalog shows DSMBs.

 

[Edward3c]

Hello everyone, I have a decline fully closed(can only inflate orally) DSMB. I think this is good for deploying form shallow water before or during my safety stop with a spool. My question is, if I was going on a wreck dive with strong current where I would need to deploy my DSMB at say 30m so the boat can follow me, would the decline DSMB be hard to inflate and the spool might not have enough line. So I would probably have to get a reel and what type of DSMB do you recommend?

If you fill a SMB at depth is going to burst, as explained by your instructor from Boyle's Law. I'd suggest getting some training on the use of SMB and DSMBs there is a big difference.

 

[Divin'Papaw]

This is what I have: Tecline Closed Buoy with D-ring 117cm Scuba Tech Diving Buy and Sales in Gidive Store

You can shoot that bag from any depth as it has a relief valve. The deeper you are, the less air you need to put in it due to the expansion of the air as it ascends. But you do need to make sure you have enough line! Much below 20-25 meters you will want a reel, not a spool. You need to account for the current as the bag will not go straight up but rather it will ascend at an angle. You probably want at least 50% more line than your depth, but that is a guess. Others may have a more precise calculation.

 

[Boarderguy]

"Fully closed" is not synonymous with SMB. Assuming OP meant Tecline when they wrote "decline", their catalog shows DSMBs.

Thanks, often they are described as such and I did not look up the aforementioned one. He gave us a link and is a great option.

This is what I have: Tecline Closed Buoy with D-ring 117cm Scuba Tech Diving Buy and Sales in Gidive Store

That is perfect and a DSMB. Sorry for the confusion on my part. The "oral" inflate is in reality meant to be used with an LP hose. Just push it onto it and let it launch. No big breaths or exertion on your part.

For a deep launch you'll want a spool or reel with at least 50% more line than depth you're at. This helps to take into account scope, or lateral movement of the bag due to current throughout the water column. Wind or reel as you ascend. Practice shallow before you risk taking a very fast ride up from 30m.

 

[inquis]

117 cm is good for training and fine for small chop. Practice deploying from 10m; conveniently, it only needs to be half full at that depth.
For more substantial waves, 1.8-2m would be much easier for the boat to see.

I normally use a 40m spool, but it's usually deployed from 21m. A reel is easier to wind up, but it's also more bulk/weight and easier to tangle. I'd suggest sticking with a spool for now. Even at a 45 degree angle, a 40m spool works for a ~30m dive.

 

[johndiver999]

Technically, you only really need the extra scope when there is variability in the velocity of the current in the water column. In other words, if the current is uniform the bag will go straight up and only be affected by wind when it gets to the surface.

As a practical matter, having a bunch of extra line (scope) is necessary when the current is strong or you will be pulled toward the surface (against your will). Not that big of a deal, but after it hits the surface you sometimes have to wait a few moments to determine how hard the float is going to “pull on you”, and adjust your buoyancy appropriately to compensate without exerting yourself.

You can remain heavy and somewhat ride it up when the surface is screaming and the bottom is stopped; which can happen when there are distinct thermoclines.

 

[MacDuyver]

Hello everyone, I have a decline fully closed(can only inflate orally) DSMB. I think this is good for deploying form shallow water before or during my safety stop with a spool. My question is, if I was going on a wreck dive with strong current where I would need to deploy my DSMB at say 30m so the boat can follow me, would the decline DSMB be hard to inflate and the spool might not have enough line. So I would probably have to get a reel and what type of DSMB do you recommend?

I've done wreck dives in areas with some rippin currents, and the good DM's/charters will include this contingency in their plan/brief. I would contact one of them in the area you'll be diving and see what their practices/recommendations are.

I'd be going with a reel that will hit the surface from depth.

dificulty of manual/oral inflate from depth is kinda dependent on your proficiency level. You don't need to get much air into it at depth since it'll expand as it rises.
I've just got the XS Scuba one, which seals itself and has an overpressure valve. I've shot it from 120ft. I have a 150ft spool because that'll work at any depth I need it to plus a little extra.... provided I don't drop it and then have to recover 150ft of line. it works fine.