Please Educate Me on Dive Flags and SMB's

[ooliviaik]

My husband and I recently got open water certified while vacationing in the Riviera Maya. While there, our instructors had what I believe are SMB's (they looked like tall, skinny, orally-inflated flags that rolled up when not in use). They inflated them right after we descended and pulled them along with us as we dove. I assumed that this was so the boat could see where we were to come back and pick us up (there were 2-3 groups on each boat trip diving in different locations). We also had a moderately strong current.

Now that I am reading more, I am getting confused about when to use these SMB's and when to use dive flags. I don't recall reading much about this in my training. I have read several threads, but I keep seeing conflicting information. Some people say it is required to always have a dive flag that you tow along. Others anchor a dive flag and stay close to it. Still others don't use one at all and think they are more dangerous than not using one. As for the SMB's, our instructors had them up the whole time and towed them. On here, though, it seems most people don't always use theirs and only do if they make an unexpected ascent. Others only inflate theirs during the safety stop.

Needless to say, I am confused. When do I use a dive flag and when do I use an SMB? Do I use them the whole time or just part of the dive? Is it different in lakes versus oceans? What about shore diving versus ocean diving? Can an SMB just be used as a dive flag like my instructors did?

Any set of guidelines would help. Thanks!

 

[tursiops]

All of the above.
Local regulations may mandate a dive flag (Florida is an example). Mostly, local regulation are silent on this, but there may be common practices locally.
Anything that can be seen by a boat if you need to be followed is the point, and SMBs will do the job, even though that is not their design intention.
You are probably not wrong to tow a dive flag if on a drift dive so the following boat can find you.....but there is the US dive flag (red with white diag stripe), and the international dive flag ("Alpha"). No need for more than one for a group diving together.
Best practice? Always have an SMB handy, with a long enough line on it that it could be used as a marker on a drift dive. check local regulations as to whether a flag is needed, and if so, which one.

 

[2airishuman]

Good questions.

Dive flag - purpose is to let boats know you're there so they can avoid the area. When you dive from a boat, typically the boat flies the dive flag. If you dive from shore, you pull a dive flag on a float. While required by law in most U.S. jurisdictions, the wisdom of using them varies depending on the location, because they are unhelpful if the local boaters do not know what they are.

I have two dive flags and use them on some shore dives. The smaller one is really only for compliance purposes and is on a handy little inflatable float. The whole thing packs up into a neat package and is ideal for places that require a dive float but where boats are not actually a hazard. The larger one is attached to a milk crate wrapped with a bicycle inner tube and is what I use if I'm serious about keeping boats away.

SMB - purpose is to let your surface support (usually a boat) know where you are, and in some cases, other information about the progress of your dive. Can secondarily be used as an easy means of ascending at a controlled rate or staying at a particular depth, such as for a safety stop or (for technical divers) decompression stop. With practice, and the right kind of SMB, it is possible to launch an SMB while still at depth. Perhaps the most common use is to signal the boat at the end of drift dive.

I generally carry two SMBs on my dives. One is a fat 6' tall one with SOLAS reflective tape on it that is suitable for emergency use if separated from the boat, and that can be launched from depth. The other is a 28" long inflatable orange baton, that is suitable for more routine signalling at the surface. In benign areas I just carry the smaller one. I also carry a signal mirror and a loud whistle.

 

[DanSinks]

I actually prefer not having to have a flag with me, so have an SMB, but it depends on the situation. Having hands free for other things is a plus. When dive buddies don't pay attention and get tangled in the flag rope it becomes a mess.(This never happened to me, but I've heard about it) I do mostly boat dives so the boat will have a big flag and be anchored(not drift dives)

 

[ooliviaik]

Thank you so much for your help! So, it seems it would be prudent to have an SMB no matter where I am diving in case I get separated from the boat group. As for a dive flag, that would be best if I am shore diving as my dive boat would already have a flag if I am boat diving.

 

[tursiops]

As for a dive flag, that would be best if I am shore diving as my dive boat would already have a flag if I am boat diving.

It depends on what kind of boat diving. A drift dive from a boat probably requires some kind of surface float for the boat to follow, so it depends on whether there is a boat-provided dive guide in the water with you, because he/she will likely ahve the flag (or SMB, whatever that operation uses).

Whether a flag is needed for shore diving depends on whose shore.

 

[johndiver999]

If you are in a strong current then towing an smb on a reel line is not an optimal solution. The smb will generate excessive drag and will be pulled sideways and possibly even pulled under the water.

A better solution is a proper surface float that is designed to be towed and generates reduced drag due to being streamlined. These floats can be configured with a dive flag.

An smb is very useful as a marker at the surface. If they have an over pressure relief valve, they can be deployed at depth and tethered by string on a reel or spool and used to assist in an ascent. If the current is mild and/or the depths are shallow, then towing an smb is not a problem.

 

[2airishuman]

Thank you so much for your help! So, it seems it would be prudent to have an SMB no matter where I am diving in case I get separated from the boat group. As for a dive flag, that would be best if I am shore diving as my dive boat would already have a flag if I am boat diving.

In general, that's correct.

FWIW, most casual divers who dive with a dive operator do not have an SMB. Whether it's important to carry one depends on where you're diving. In a quarry or small lake it isn't necessary.

 

[TMHeimer]

ooliviaik,
Dive flags:
All charters I've taken flew them.
Shore dives:
2 things--the Law and using common sense.
The law probably requires you to have one everywhere imaginable. Whether towed or anchored (how do they know which you're doing?).
Use common sense. Connecticut in July I take mine. Nova Scotia anywhere anytime no--no boats where I dive, so enjoy hands free.

SMB--again, common sense. Diving at the Destin jetties in NW Florida where a miscalculated current change could send me to Cuba, yes. Paddy's Head, Nova Scotia or Merwin Point, CT, no.

 

[Saniflush]

Welcome to the best sport in the world!