Ask Livingseas.

Let’s start our discussion by looking at the line itself. What kind of line is it, and why is it at the dive site in the first place?

It could be a mooring line, which is usually anchored to a large concrete block on the seabed. Boats secure themselves to the mooring using this line.

Or it could be a diving shot line, which is typically deployed to mark a dive site. A boat may also sometimes use it to locate a submerged wreck. This type of line is often tied to a weight and is not securely anchored to the bottom.

If the line was not deployed by you or your boat crew, it could very likely have been placed by a previous group of divers to mark the location of their ascent or descent. In this instance, the line is often connected to an inflated surface marker buoy at the surface, with its spool is tethered to a rock or coral structure at the bottom. Such lines serve as a reference for divers visiting a particular dive site repeatedly for survey or conservation work, among other purposes.

From these examples, you probably have a sense of when it is appropriate (and not) to hold on to the line. In situations where the line is not anchored securely to the bottom, touching or tugging on the line may dislodge the weight or move the line, and render the location reference useless.

However, even if the line is securely anchored, I still wouldn’t recommend holding on to the line unless the current is so strong that a diver is unable to kick to maintain position next to the line.

I think it’s important that we use the line as a visual reference during a descent or ascent, and not as a means to control or manage buoyancy. A diver should actively manage his buoyancy whether he is holding on to a line or not.

Consider the situation where a diver is holding on to a line and ascending, but does not bother or remember to deflate his BCD. The diver does not realise that the BCD has inflated to the point that he is very buoyant. This could result in a runaway ascent if the diver, for some reason, loses his grip on the line.

Ideally, a diver should avoid holding on to the line during an ascent or descent. Instead, he should use his kicks and buoyancy to stay close to or within visual range of it. If the line is about an arm’s length away, one strong kick would bring the diver close enough to grab the line if need be. The rest of the team then forms up beside the diver, so everyone is able to grab the line too, if the situation calls for it.

Finally, when ascending next to a mooring line, divers should remember that there is likely a boat tethered to it. If there is a current, both the boat and the diver will be on the same side of the line, which means the diver is ascending directly below the boat. This can be dangerous if neither the boat crew nor the divers are aware of their respective positions. If this is the case, then make sure you check upwards to see if there’s a boat on the line, and if so, then shoot an SMB and drift off the line to be on the safe side.

Moral of the story: Don’t hold on to any line while ascending or descending if you can help it!

Leon Boey

Leon Boey is a GUE, HSA and PADI instructor based in Singapore and Bali. He runs the dive education centre Livingseas in Singapore, Bali and Jakarta. Diving since 2005, he first fell in love with wrecks. He enjoys all sorts of diving, and loves being surrounded by fish.

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