Different types of SMBs, what are your opinions?

[krillo]

Hi!

I am a releatively new diver. Recently me and my diving partner have decided to start getting our own gear. The topic for this question is about SMBs. When reading most of the topics in this forum it seems to me that only "tubular" SMBs are used. However I have seen other types used - in the lack of a better description, the floating donuts with flags.
Are there any reasons that you do not use these? The reason we would use this is to signal to others that we are in the water. We often do shore dives in places were boats can get close.
Please excuse my ignorance in this matter.

 

[gsk3]

In general, the tubular ones are "SMBs," whereas the donues with flags are "dive flags." There are also "lift bags," which look more like inverted triangles.

SMBs are typically used for drift diving or to tell a dive boat where you are/that you are beginning your safety/decompression stop.
Example: http://northeastscubasupply.com/sto...-7-39-Surface-Marker-Bag-Orange/prod_674.html

Dive flags are typically used as a legal/safety requirement to tell other boats to stay away (and laws generally stipulate that other boats stay some specified distance from a dive flag). Consequently they are used (and often required) on shore dives or river dives with boat traffic.
Examples:
http://northeastscubasupply.com/sto...ts/Diver-Down-Inner-Tube-Float/prod_1300.html
http://northeastscubasupply.com/store/Dive-Flags/Dive-Flag-Floats/Diver-Below-Float/prod_1295.html

Lift bags aren't really used to mark your position but rather to provide lift to get an object up from the bottom. They are a good idea when raising objects even if you have enough lift in your BCD to get it up, as if you drop the object you're taking a very fast elevator ride to the surface, which puts you at risk for a gas embolus.
Example: http://northeastscubasupply.com/sto...to-300lb/100-Dive-Rite-Lift-Bag/prod_506.html

 

[DCBC]

Welcome to SB. The only stupid question is the one unasked...

The tubular units are easy to deflate, store and carry; the inner tube isn't. The purpose of an SMB is not to replace the diver down flag, but to indicate either the diver is surfacing, or the diver needs assistance from the surface.

The World Diving Federation (CMAS) has colour coded these as follows:

Red DSMB = Indicates the position of a diver below ascending normal.

Yellow DSMB = Diver in distress, requires assistance. The buoy may be accompanied by an
attached note determining the required help e.g. ”More air”.

Red DSMB + Yellow DSMB = Red DSMB is usually sent up first to indicate a normal ascent and to the diver’s position. The second DSMB, Yellow, is deployed to say I now need assistance. Again a note may be attached to determine the required help.

I have no idea why these colours were assigned the way they are. But this has been accepted in 17 countries.

Another factor worthy of consideration is the sea conditions that are reasonably present when you dive and the distance away from the boat/shore you are likely to be. I use an 8 or 10 foot SMB because of the wave conditions that I dive in (anything less wouldn't work as well). Obviously if you are diving in-land lakes or rivers, this isn't as much of a concern.

Hope this helps.

 

[krillo]

Thanks guys, really helpful answers!