Teach me about SMB's?

[natew]

I've been thinking that an SMB would be a good thing to have, especially since the majority of my boat diving trips around here will take me 20+ miles off any real land mass and occasionally into areas with strong currents.

Of course, I've realized that there are about a thousand different ones, and types with different uses. Can I get away with a super cheap one like this, Amazon.com: 45 inch Scuba Diving Dive Signal Tube with Inflator… , or do I need like one of these hundred dollar deals?

What are the differences in types?
Would it be advisable to use one always when surfacing/on surface or just when there is trouble?
How big? These things seem to range from four feet to like twelve feet tall.
What about different messages written on them? Diver below vs blank vs emergency vs wtf?

Anything else I don't know about?

 

[Jorgy]

I carry a CBPF-35 with a 35 ft mini-spool on all my dives

Personal Floats Safety Sausage Tubes

It works for all applications, lift bag, DSMB on a drift dive and surface marker....

I practice deploying it after my safety stop on a regular basis, just in case.......

Hope this helps......M

 

[Brian Sharpe]

A 4ft SMB is probably fine for diving in areas where it's unlikely there will be anything much in the way of surface swells (lakes rivers etc) but if you're diving in the ocean you may want to consider a bigger one just to be seen in a real emergency.

 

[TSandM]

You're right -- there are a lot of SMBs out there. They vary in size, shape, lift, method of inflation and method of deflation. In general, a 1m bag is useful in water where there is little chop or swell. A larger (2m) bag may be better in open ocean conditions, where swell can be expected.

If you intend to deploy the bag at depth (which is nice sometimes, to let the boat know where you are BEFORE you come up) then it's pretty necessary to have some way of letting excess pressure escape from it. Some bags are simply open at the bottom, which permits this -- but then you have to be very careful to keep the bag upright during deployment and at the surface, or it will lose its air and sink. Other bags have some kind of overpressure valve which will keep the bag from popping on ascent, but will keep it full on the surface.

Bags vary in how they are inflated. Some are inflated orally, some by LP hose, and some by purging a regulator into them. Some can be inflated by more than one method. The very inexpensive ones are generally deployed at the surface, by blowing into the end of the bag.

I can't tell for sure by looking at your ad, which features this bag has. But given how tightly it is rolled, I don't think it has any kind of overpressure valve. And I don't see an oral inflation tube sticking out anywhere. So I suspect this is one of the very simple ones, which is designed to be inflated and waved only on the surface. This is not what I would recommend. I prefer one that I can send to the surface the minute I know I'm not going to be where the boat thinks I am, because the closer to the boat I can deploy the marker, the more likely it is that they will see it.

 

[Splitlip]

I personally like the hundred dollar plus ones.

I shoot 1M (6#), 1.5M (40 #) and 2M (52#) from depth. I want it up there when I leave the bottom so surface support can mark me and also as protection from other boats.

The 1M is way undersized IMO to be easily visible. too narrow to be easily spotted. (about as big as the one in your link.) I keep it as a backup.

Whenever I post the attached link, the thread dies. But when you see the location of the boat, you'll understand why I have a big one.

JDC032.flv video by mm2002_bucket - Photobucket

 

[TSandM]

I don't know . . . as someone who has boat tended for divers, I have found a 1m bag to be pretty easy to spot, even in moderate swells. I think a lot depends on the degree of vigilance of your crew, and also when you shoot the bag. If you get a long way from the boat before deploying it, a bigger one is definitely better.

 

[Splitlip]

I don't know . . . as someone who has boat tended for divers, I have found a 1m bag to be pretty easy to spot, even in moderate swells. I think a lot depends on the degree of vigilance of your crew, and also when you shoot the bag. If you get a long way from the boat before deploying it, a bigger one is definitely better.

I did not mention swells, although they can be a player.

The 1 meter markers don't print well enough in the sun or on the horizon IMO because they are so narrow. I have a halcyon. 1 meter and 6# of lift. The DSS is even smaller (in girth) .
The one in the video link is only 1. 5 meters, but look at it's thickness. It has 40 # of lift. Yes, we depend on the vigilance of the boat crew, but we also give them as much help as we can.

It's a regional thing I guess. We drift dive. Current can be zero on the bottom while mid water it can be 5 kt. It can be different directions depending on where we are in the water column. It takes a savvy captain to track his charges, but I've still spent 30 minutes and more trying to locate divers with one of those little sausages (which are mandatory here) deployed near the surface. When the divers leave the bottom, it is a good 7 minutes before they hit the surface. My marker goes up as soon as I thumb the dive.

The other issue in addition to the crew marking us, is to make a big statement so other boats don't run us down when we surface. Buddy teams can be hanging spread out like marbles, and there is no way the boat crews can be everywhere at once. We dive where the fishermen fish.

 

[TSandM]

Thanks, spitlip, those are interesting factors for deciding which SMB to use, and none of them have really pertained in places I have dived up until now.

 

[formula1mb@aol.com]

Here's an interesting one, has a mini cylinder you top off from your main tank. Than when you want to deploy, you unroll it, attach to your reel and crack the cylinder open to take it up. Also has the sealed bottom so it doesn't lose all the air on the surface. One cool thing with this one is that it's the same to launch whether at 10 ft or 70 ft----with some of the bigger ones, launching at shallow depths is trickier because you have to fill it more due to the lower expansion.

A.P.Valves

 

[natew]

Thanks for the great info guys! Sounds like for the most part I want something around 4-6ft in height, a good amount of girth and that can be deployed from a safety stop using a reg. That gives me a much better place to start looking.