Browsing Tag smb
When to deploy a surface marker buoy (SMB)
The answer might seem obvious, but many divers neglect to shoot the bag early, and end up surfacing a long way away from their dive location and their boat. I’ve heard many stories of divers drifting for hours because of their boat crew could not locate them. Don’t let that happen to you.
I would always consult the diving conditions when deciding when to deploy my surface marker buoy. Generally, you should shoot the bag when you are starting the ascent in a normal dive, or whenever you are leaving the reef, whichever happens earlier.
However, if the conditions are bad, such as when there’s a strong current pulling you away from the reef, then you would need to deploy your SMB as early as possible before you get swept into the open ocean. Don’t delay getting the SMB to the surface!
Consider a situation where this wasn’t the case, for example, if the diver ascended to a safety stop before deploying the SMB, or in a situation where the spool wasn’t long enough to reach the depth the diver is at.
In these situations, the time taken to ascend to a shallower depth, coupled with the current, could mean that the diver drifts far away from the dive site. Given that the boat would be waiting for the diver to ascend near or on the dive site, this could mean the boat captain will not be looking out towards the ocean where the divers eventually surface.
Needless to say, it’s much harder for the boat captain to spot divers floating in the open ocean than next to the reef. Personally, I wouldn’t take it on faith that the boat captain will always know where to look for you when you surface. Do your part as well to guarantee that he can see you!
Finally, if you’re wondering whether to use an inflated SMB throughout your dive, read this article that discusses it in depth.
Should we use an inflated surface marker buoy throughout a dive?
Most divers recognise that the surface marker buoy, or SMB for short, is an essential piece of dive equipment. However, not everyone agrees on the point of whether to use it throughout a dive.
Some divers inflate a highly visible surface marker buoy before descending, and the buoy follows the group throughout the dive. You might see this happening at shallow bays or dive sites where boat traffic is high. It seems like a good idea, since the marker lets boats know that there are divers below, but is it really?
Now let’s look at what could go wrong in such a scenario.
Firstly, having to tow something along (in this case, an inflated marker on the surface connected to a line held by an underwater diver or attached to his BCD) is not only tiring but also hard to manage. The diver holding on to the reel or spool has the responsibility of releasing and taking in the line according to changes in depth. If your divemaster had to manage this, do you think he would have the capacity to also lead the dive and keep track of all the divers?
What’s more, divers might also swim into the line and get entangled, making the dive even more difficult.
Secondly, there are often winds or surface currents at many dive sites. This force pushing on the surface marker buoy may oppose the underwater current or the direction taken by the divers. Fighting the drag and getting the SMB to follow you during the dive would be a challenge.
Lastly, even though the surface marker buoy serves to warn boats, people do still make mistakes. In my years of diving, I’ve seen more than one boat drive right over an SMB. If the SMB line was attached to a BCD, what would happen if the line got caught in a propeller? I shudder to think of the possibilities.
In my view, surface markers are useful only when divers are surfacing or in situations where the conditions are such that the boat must follow the divers throughout the dive (for example, strong current, heavy surge and open ocean diving). The method of diving with an inflated SMB throughout a dive would not be a first choice for me, when planning dives in relatively good conditions.
What’s more important is ensuring the diver has good skills, especially buoyancy in this case. If a diver had excellent buoyancy and awareness, he would be aware of the loud noise generated by an approaching boat, and stay close to the bottom.
Finally, let’s consider two divers with excellent buoyancy skills: One has an inflated SMB attached to him and the other has none. A boat passes overhead. The diver with the line, through no fault of his own, might very well get pulled up into the boat’s propeller. The diver without the line, who upon hearing an oncoming boat, stays close to the reef or bottom and faces no such risk.