Purpose of an SMB?

[dougchartier]

On my last dive trip to the Galapagos, one of my dive mates highly recommended getting an SMB with a spooled line instead of the mouth-inflatable safety sausage I had (the liveaboard recommended them for the trip -- I'd never had one before). He said that he oftened deployed the SMB at 15', when he did his safety stop.

I have to admit that his SMB looked quite cool, particularly since you could inflate it with your second stage. But I'm wondering why one would deploy an SMB while still underwater. Can someone please explain?

Thanks in advance.

 

[CalgaryDF]

Its deployed so the boat knows where you are while you do your safety/deco stops. It also keeps other boats aware of where you are, and provides you a reference for depth. If you are hanging on an anchor chain its probably not really necessary, however can be good if you get lost or have to ascend away from the boat.

 

[fnfalman]

There are safety sausages and then there are surface buoy markers (SMBs). Safety sausages can only be inflated by mouth and generally designed to be blown up when you're on the surface already. An SMB can be deployed while you're underwater by oral inflation or by purging the second stage.

An SMB tends to be taller and wider. Either way, you use them to identify your location.

People usually deploy an SMB when they do their drift dives so that the boat can see where they're going and follow them.

People also deploy an SMB if they were in a dive and got swept away by current and couldn't find the anchor line. That way they can do their safety stop or even decompression stop and hopefully the boat can see them.

Some SMB/safety sausage comes only in orange. Some come in neon green/neon yellow. Some have reflective stripes, some don't. Some have pockets for mirror, whistle and light stick. Some have a pocket on the tip for attaching light stick/small flashlight/beacon light.

How much do you want to spend?

 

[sabbath999]

There are many reasons one would use an SMB. One is that you deploy it on a drift dive so the boat can easily see where you are. Another is that you can mark your reel at 15 feet and use it to "hang on" to for your safety stop. Some can be used as a secondary lift bag as well.

There are other reasons as well.

You also don't need to shoot them from only 15 feet down, you can shoot em from about any depth you have the line for... in fact, it is easier to shoot them from 60 feet than 15.

 

[TSandM]

I think the biggest purpose for deploying a bag at depth is that, if you know you are being carried away from the boat, you can get something on the surface to mark your whereabouts while you are still close enough to it for someone to see the marker. If you have to wait until you are on the surface, you may be a long ways from the boat, and they may have trouble picking you up, especially in unsettled seas.

The other reasons for deploying underwater are also valid, but the one above is the most urgent, I think. I have to say that, as a sometimes boat tender, it is tremendously reassuring when you see that bag come up, and you know where your divers are, and that they are okay.

 

[Ben_ca]

The why is easy... actually doing it well takes some practice and training.

 

[Crush]

But I'm wondering why one would deploy an SMB while still underwater. Can someone please explain?

Thanks in advance.

SMBs are typically used if required by law to mark a diver's location at all times during a dive. Hence, they are deployed at the surface prior to a dive and towed about. A rescue sausage is often deployed at depth and (depending upon its design) can be orally inflated, inflated with your reg, or both.

A rescue sausage can be used as an SMB - on a dive last year a passing boat cut the line between us and our SMB - we deployed a rescue sausage and continued on with the dive, in full compliance with all local ordinances. In addition to not being fined, our boat managed to keep track of us on a drift dive in very choppy water - had they not been able to stay with us, our extraction from the water may have been delayed.

At the surface an SMB or a rescue sausage can serve a welcome extra flotation in the event that your extraction is delayed. However, if you want to be spotted in choppy water, size does mater - get a long, bright rescue sausage.

In the (very unlikely) event that there is a catastrophic failure of your drysuit and/or buoyancy device, a rescue sausage can be rapidly deployed to "tether" you to the surface via the spool of line. Remember that a rescue sausage may have a buoyancy of about 25#, but a fit swimmer with fins will have a very difficult time raising 5# to the surface from depth. Summary: it is much easier to pull yourself up using a rescue sausage/spool than to swim up.

Final note: everyone has their own opinion on what kind of spool to use with a rescue sausage. I prefer a finger spool as, owing to its simplicity, it will not "jam." Once un-clipped, if the spool gets yanked out of your fingers it will continue to un-spool and may eventually fall past you as opposed to a cave-style reel which (if jammed) will rocket to the surface with your sausage. Finger spools are also smaller and cheaper.

Happy diving!

 

[fnfalman]

And whatever you do, please stow the finger spool/cave spool properly or else you'll find out that it had unraveled and wrapped around your feet.

I've only seen it happened once, but if it had happened once, it'll happen again to somebody.

 

[AfterDark]

The why is easy... actually doing it well takes some practice and training.

Wow that looks hard!:sarcasm: I bought one this season. Took it diving and deployed to try it out. Where does the training come in? Is there a PADI course for that?

 

[Crush]

Wow that looks hard!:sarcasm: I bought one this season. Took it diving and deployed to try it out. Where does the training come in? Is there a PADI course for that?

There is a PADI course for everything! I am taking "underwater battery changing" this weekend.