DSMB norms in Cozumel?

[nimoh]

I'll be happy to voice a different opinion. By your logic, a tube having a 1-way flutter valve at the bottom should be referred to as a "DSMB," but a poorly/cheaply designed tube advertised as being deployable at depth but unfortunately lacking a 1-way flutter valve at the bottom should be referred to as an "SMB"? I'm sure there are various features in addition to a flutter valve that would optimize an SMB design for deploying at depth, such as an overpressure valve, but in my opinion, the presence or absence of features that makes some SMBs better for deploying at depth than others doesn't affect whether some deserve to be called "DSMBs" but others only deserve to be called "SMBs." I still think the addition of a "D" doesn't provide any additional useful information to what would be conveyed by simply saying "SMB" in the context of a typical discussion about carrying/using one.

I agree, my point was just that some SMBs have features that make them better for deploying from depth (IMHO), but I don't claim to have hard and fast rules to make the distinction.

 

[Mossman]

I still think the addition of a "D" doesn't provide any additional useful information to what would be conveyed by simply saying "SMB" in the context of a typical discussion about carrying/using one.

I believe the context of the typical discussion about the SMB is its use in an emergency. If out of sight of the dive boat, the bright coloring of the SMB sticking several feet out of the water may be more recognizable to those searching for lost divers than a head bobbing in the waves.

On the other hand, in Cozumel, the DSMB is routinely deployed at depth, not as an emergency measure, but to warn nearby boats that divers are surfacing and to alert the DM's boat that the group is nearly ready to be picked up. The additional useful information is that the DSMB can be deployed at depth because it's on a line, usually (but not always) attached to a reel.

 

[mstevens]

I have come to the conclusion that this board could argue anything passionately.

You're so wrong about this I don't even know where to start...

 

[Ron Lee]

You're so wrong about this I don't even know where to start...

I believe that your assertion that he is wrong is incorrect.

I will admit that this thread is the first time that I have seen the acronym "DSMB."

 

[Lorenzoid]

I believe the context of the typical discussion about the SMB is its use in an emergency. If out of sight of the dive boat, the bright coloring of the SMB sticking several feet out of the water may be more recognizable to those searching for lost divers than a head bobbing in the waves.

On the other hand, in Cozumel, the DSMB is routinely deployed at depth, not as an emergency measure, but to warn nearby boats that divers are surfacing and to alert the DM's boat that the group is nearly ready to be picked up. The additional useful information is that the DSMB can be deployed at depth because it's on a line, usually (but not always) attached to a reel.

My interest is solely in the terminology: "DSMB" vs. just plain "SMB". What benefit did you gain by not wording it like this?

"I believe the context of the typical discussion about the SMB is its use in an emergency. If out of sight of the dive boat, the bright coloring of the SMB sticking several feet out of the water may be more recognizable to those searching for lost divers than a head bobbing in the waves.

On the other hand, in Cozumel, the SMB is routinely deployed at depth, not as an emergency measure, but to warn nearby boats that divers are surfacing and to alert the DM's boat that the group is nearly ready to be picked up. The additional useful information is that the SMB can be deployed at depth because it's on a line, usually (but not always) attached to a reel."

In the context about deploying an SMB at depth, what benefit is there to writing "the DSMB is routinely deployed at depth" as opposed to writing "the SMB is routinely deployed at depth"?

Attaching a line to an SMB doesn't make it a DSMB; it's still the same tube, just with a line attached. If I buy an SMB from a shop, it doesn't have the line attached. If I attach a line to it, does that affect the label on the box that says what I bought is an "SMB"? One doesn't even typically attach the line until one deploys it--underwater. So I should say I "keep my SMB stowed" on my dive, and at some point during the dive I attach a line and a reel and--voila--"deploy my DSMB"? You mean while underwater I transformed an SMB into a DSMB? I just can't see any useful reason for both terms to exist, since in every instance I can think of it's perfectly clear what is being referred to without having to include the "D" as a prefix to "SMB". The addition of a "D" prefix just isn't useful unless there exists some kind of commonly used SMB that is impossible to deploy underwater.

---------- Post added February 24th, 2014 at 12:58 PM ----------

A dive flag float? Maybe that's a type of "SMB" that is not deployable underwater? But that's generally not what people are referring to in these discussions. They're referring to those long tubes.

 

[macado]

I carry a DSMB with me on every dive, especially in Cozumel or any sort of drift diving. Whether I deploy it or not it depends on certain factors. For example, if i'm diving with a group and ending my dive at the same time as the divemaster, I won't bother deploying it since i'm already with that group. If i'm diving in the north where seas/waves/currents can be unpredictable I always inflate mine even if the DM has already inflated theirs. It gives the boat captain another reference to locate the dive group in rough waters. The same rule appears for places like Maracaibo/Punta Sur Sur or if I'm separated from the group. I've been on dives in Cozumel many times where weather turned crappy fast, heavy downpours, making it very difficult for a boat captain to locate an SMB on the surface.

Here's another thing, discuss whether or not you want to deploy your SMB with the boat crew/dive master BEFORE the dive. It can be part of your dive plan. I simply explain that if I get separated or other conditions, I am going to shoot an SMB. Mine has my name in huge letters written on both sides so they can identify me. Tell them what to expect so they are not surprised.

In the event you do get separated from the group waiting until you surface to deploy your DSMB/SMB (whatever you want to call it) is a poor choice. You want to give the boat captain a better chance of spotting you before you drift too far out of visual range. If you're lost and wait until the surface to deploy an SMB, currents may have already pushed you a significant distance making it harder for the boat to visually locate you.

[/I]I just can't see any useful reason for both terms to exist, since in every instance I can think of it's perfectly clear what is being referred to without having to include the "D" as a prefix to "SMB". The addition of a "D" prefix just isn't useful unless there exists some kind of commonly used SMB that is impossible to deploy underwater.

SMB and DSMB are technically two different products but the term is often used interchangeably. It's all semantics. A DSMB typically has an (OVP) over pressure relief valve so that if it is shot from depth the pressure can safely escape. An SMB on the other hand does not have an OVP valve or an opening at the bottom where excessive air can escape/vent; It is designed to typically only be inflated at the surface.

I agree with your point. There is nothing stopping someone from putting an SMB on a reel and inflating it from depth, thereby making it or calling it a DSMB However in the event too much air is added at a significant depth you risk over-inflating the SMB and damaging it. I've seen plenty of SMBs inflated at depth without issues so this isn't always a concern, especially when inflating from a shallow depth. With an SMB on a reel, I only inflate partially at a depth of 10m/33fsw and let the expanding pressure do the work. Example: 33fsw is 2ATA, gas volume compresses 1/2. If inflate around half full at depth of 33fsw/10m, it should be full on surface

With that being said, A DSMB is a much better choice from inflating at depth because you'd have to worry about over expansion since they have a pressure relief valve or a way for excess air to vent.

 

[Mossman]

[/I]In the context about deploying an SMB at depth, what benefit is there to writing "the DSMB is routinely deployed at depth" as opposed to writing "the SMB is routinely deployed at depth"?

Attaching a line to an SMB doesn't make it a DSMB; it's still the same tube, just with a line attached. If I buy an SMB from a shop, it doesn't have the line attached. If I attach a line to it, does that affect the label on the box that says what I bought is an "SMB"? One doesn't even typically attach the line until one deploys it--underwater. So I should say I "keep my SMB stowed" on my dive, and at some point during the dive I attach a line and a reel and--voila--"deploy my DSMB"? You mean while underwater I transformed an SMB into a DSMB? I just can't see any useful reason for both terms to exist, since in every instance I can think of it's perfectly clear what is being referred to without having to include the "D" as a prefix to "SMB". The addition of a "D" prefix just isn't useful unless there exists some kind of commonly used SMB that is impossible to deploy underwater.

For that matter, my diving rig is perfectly usable for breathing on the surface as well as underwater. Yet the powers that be insist on calling it Self-Contained Underwater Breathing Apparatus. Why not just Self-Contained Breathing Apparatus or SCBA. I hereby demand that the U be removed from the acronym as being inaccurate!

 

[Lorenzoid]

For that matter, my diving rig is perfectly usable for breathing on the surface as well as underwater. Yet the powers that be insist on calling it Self-Contained Underwater Breathing Apparatus. Why not just Self-Contained Breathing Apparatus or SCBA. I hereby demand that the U be removed from the acronym as being inaccurate!

Firefighters and perhaps others on the surface also use what you might call self-contained breathing apparatuses. There exist some self-contained breathing apparatuses that are impossible (or at least highly inadvisable) to use underwater. So in your example, the "U" arguably conveys useful information. But as I said, I've never seen an SMB or read a discussion about an SMB--that is, a tubular inflatable thing--of a type that was truly not deployable underwater. Some are better designed for that than others, but as far as I have been able to determine, the manufacturers envision it being possible to attach a line/reel to any of them so you can deploy them underwater. When someone talks about "deploying a DSMB for the safety stop," the "D" is superfluous. He would be conveying the exact same information if he were to instead talk about "deploying an SMB for the safety stop." Even minus the "D" everyone understands what is meant.

 

[dbulmer]

Excerpt from British Diving Safety Group:
BRITISH DIVING SAFETY GROUP
Recommendations Concerning the
Use of Surface Marker Buoys

Surface markers buoys (SMBs) can be used in many diving scenarios; they can be
used to warn boats of the presence of divers or to maintain communication with the
surface support team. SMBs remain at the surface for the duration of a dive; the
diver controls the line leading to the SMB using a reel. It is recommended that SMBs
clearly indicate that there are divers below, and they should ideally include the
international Flag ‘A’ as part of their design.

A Delayed Surface Marker Buoy (DSMB) can be useful in some situations as an
alternative to an SMB. The DSMB is initially carried underwater by the diver in a
deflated state, then at some stage towards the end of the dive, the diver deploys the
DSMB while still underwater, using a reel to feed out a line. This line can then be
used as an ascent aid, and the buoy can show the support team the location of the
divers.
DSMBs can also be used to indicate an emergency situation. Some divers carry two
DSMBs of different appearance, with one being used routinely, and the other only
being deployed to indicate an emergency.


An SMB always remains inflated at the surface whereas a DSMB might not ie it is "D"flated

 

[Lorenzoid]

Excerpt from British Diving Safety Group:
BRITISH DIVING SAFETY GROUP
Recommendations Concerning the
Use of Surface Marker Buoys

Surface markers buoys (SMBs) can be used in many diving scenarios; they can be
used to warn boats of the presence of divers or to maintain communication with the
surface support team. SMBs remain at the surface for the duration of a dive; the
diver controls the line leading to the SMB using a reel. It is recommended that SMBs
clearly indicate that there are divers below, and they should ideally include the
international Flag ‘A’ as part of their design.

A Delayed Surface Marker Buoy (DSMB) can be useful in some situations as an
alternative to an SMB. The DSMB is initially carried underwater by the diver in a
deflated state, then at some stage towards the end of the dive, the diver deploys the
DSMB while still underwater, using a reel to feed out a line. This line can then be
used as an ascent aid, and the buoy can show the support team the location of the
divers.
DSMBs can also be used to indicate an emergency situation. Some divers carry two
DSMBs of different appearance, with one being used routinely, and the other only
being deployed to indicate an emergency.


An SMB always remains inflated at the surface whereas a DSMB might not ie it is "D"flated

So it sounds like what the British Diving Safety Group refers to as an "SMB" is what most of us in America refer to as a dive flag or dive flag float. Regardless, in the context of the many discussions here on SB about deploying SMBs for the safety stop or to indicate an emergency on the surface, it's my understanding that everyone is referring to the long tubes that are stowed in a rolled up state, sometimes also called safety sausages. Though your quote from the British Diving Safety Group leaves me wondering if terminology might be different in Britain, I would wager that most people who want to talk about a float that they tow throughout the dive to indicate there is a diver below would use a term like "dive flag"--for example, I've seen Florida divers talk about "towing a dive flag." I will agree that a dive flag float is literally a marker buoy on the surface, but it just seems like a totally different animal than the tubes we're all talking about here when we variously use the terms "SMB" and "DSMB." I will stick my neck out and say I don't care for the British Diving Safety Group's use of the two similar terms "SMB" and "DSMB" for two very different things. Of course, I'm fairly certain that most people who have read this thread tangent don't care about it at all. I'm not sure why it bothers me so much.

If I referred to the above as an "SMB," wouldn't it raise eyebrows in the discussions here? "I'm bringing my SMB to Cozumel." I think most people associate "SMB" with a tubular thing that is carried rolled up and may be deployed either underwater or on the surface.