USE THE CONTOURS
When you dive against the water flow in a flooded cave, you don’t just swim down the middle of the cave. That’s where the flow is the greatest.
You stay close to the wall and look ahead at the contours of the section of the cave towards which you’re swimming. Then you plan your route to make sure you use those contours to shelter from the flow as much as possible.
The same technique applies when you’re swimming against the current across a seabed. Marine topography rarely consists of flat bottoms, straight lines and smooth curves. Every reef has a multitude of outcrops, slopes, ridges, canyons, bommies and other inconsistencies that you can use to your advantage.
The contours of the reef can help to make your journey across it less energy- and air-sapping. For instance, if there is a ridge or bommie in front of you, this will at least partly shield you from the current.
Just keep low, below the height of the ridge, or position yourself in line behind the bommie, and you will be able to make progress more easily.
As you get closer, look beyond the ridge or bommie to find the next obstacle you can use to hide behind. Even a slight deflection can diminish the force of the current you’re facing.
A diver swimming straight down the middle of a cave – not the best way to go against the flow.
If there are bommies or boulders close together, the contraflow will be much higher through the narrow channel between them, so choose a path where gaps between obstacles are wider.
If you have to go through a narrow gap, stay close to the side rather than passing through the centre. You will find it much easier. The same applies if you take a swim-through from one side of the reef to the other, and the current is against you. Stay close to the side of the swim-through and you won’t have to kick so hard.