Browsing Tag descend
The correct way to do a back roll
Here in Bali, we tend to dive from small boats that require a back roll entry into the water. Very often, we encounter divers who do not know how to do a back roll effectively. Some go headfirst into the water while others flip over completely and struggle to get their legs beneath them. While this can be a hilarious sight, there is a safety issue here that shouldn’t be overlooked.
When performing the back roll, the scuba tank should hit the water first. This cushions the diver from impact, and protects the neck from undue stress. Divers commonly mistakenly throw their heads back to initiate the backward roll, and this usually results in the diver hitting the water headfirst.
There’s more than one reason why this isn’t ideal. Firstly, by throwing the head back, you’re likely to hit the first stage with the back of your head. Obviously that’s going to be uncomfortable. The mask strap might also slip off the head upon impact with the water. If the diver isn’t holding the front of his mask and regulator, the mask might very well slip off and drift away. In truth, many divers have lost their masks this way.
Thirdly, if the diver isn’t able to get his legs under him quickly enough in a high current situation, then he might surface far away from the boat and the rest of the divers, or heavens forbid, near the propellers at the back of the boat.
Here is how a back roll entry should be safely and effectively executed. Before getting into position, ensure all your gear is in order: Fins securely strapped on, BCD fully inflated, mask and regulators in place.
Step 1 – Sit as far back on the edge of the boat as possible. Lean forward to prevent the tank from hitting the side of the boat as you enter the water.
Step 2 – Keep your head facing forward, and place your right hand on the mask and second stage. Check again that the BCD is fully inflated to be doubly sure.
Step 3 – Cross feet (stack one fin on top of the other) to avoid hitting anything or anyone beside you.
Step 4 – Keeping your back straight, slowly lean back, as if lying back on your bed. The weight of the tank will pull you backwards into the water. Let the weight of the tank lead the backward roll. Avoid rocking backwards forcefully as this might cause your body to over-rotate. Ideally, the corner of the bottom of the tank should hit the water first, and this should slow your entry into the water.
A nice entry where the tank hits the water first
Step 5 – As you enter the water, keep your head, hands, legs and waist in roughly the same position as while you were seated on the edge. Avoid spreading your legs as your calves might hit the edge of the boat.
An over rotation, where the head is the lowest point on the entry
Step 6 – Once the tank hits the water, move your legs in a breaststroke kick to get them under you in the quickest time possible. This should also prevent you from drifting too far into the current.
Step 7 – Signal to the boat that you are okay.
An advanced option: As you lean back into the water, turn and angle your body slightly so that it faces where the current is coming from. This brings your legs and fins around into a better position to push back against the current if the need arises.
Should I hold on to a line while descending/ascending?
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!