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Training Tips: Streamlining

Get your profile in order to improve your air consumption and underwater movement

In our series on training tips, we’ve come to one of the most often overlooked, but yet important, elements of diving: streamlining.

Streamlining relates to how small your profile is in the water. If you were to view yourself from the front as you swim through the water, the less space you take up, the more streamlined you are.

The value of proper streamlining is obvious if you’re swimming in tight quarters, such as wrecks, caves, swim-throughs, or kelp forests, but it’s actually just as important in open water. When we dive, the “smaller” we are in the water, the less energy we must use on swimming. Less energy equals less air consumed, which equals longer dives. If there are two divers of more or less equal build, but one consumes much more air than the other, a major part of the explanation will often come down to a difference in streamlining.
Streamlining underwater works in essentially the same way as with a car. The less wind resistance a car’s design creates, the more fuel-efficient it becomes. And the less water resistance our profile creates as we swim, the more air-efficient we become.

The first step in streamlining is to be observant of your body’s position. This points back to your trim, which we covered in an earlier article. The more horizontal your trim, the more streamlined you’ll be.

The next step is to go over your equipment. A good many divers bring a lot of unnecessary equipment on a dive out of a “better safe than sorry” approach. But having too much gear makes you less streamlined, especially if you leave it dangling from your BCD. There’s really no need to have a strobe light permanently attached to your BCD if most of your dives are in clear, tropical waters. Go over your gear before each dive, and leave the stuff you won’t need on the shore or boat.

The next step is to evaluate how you carry your gear. Having torches and a DSMB dangling from your BCD’s D-rings is not good for your streamlining, and poses an entanglement risk. So square things away, either by putting gear in pockets if you can, or by clipping them to a D-ring and then securing them to your body or another part of your BCD using a bit of bungee cord. And secure your pressure gauge and octopus so they don’t drag behind you in the water. You don’t want to become that most dreaded of diver: the Christmas tree, complete with dangling ornaments everywhere. Improper streamlining not only leads to entanglement risks, it also means that equipment left dangling is likely to bump against the bottom, rocks, corals, etc., which is bad both for the environment, and for your gear.

As a final step toward perfect streamlining, take a look at the length of your regulator and low-pressure inflator hoses. If these are too long, they’ll stand out from your body, creating drag and risk getting snagged. Replace them with shorter hoses that allow you the full range of motion, but no more than that. And thread your hoses the correctly to ensure they follow your body’s profile as closely as possible.

These four skills — buoyancy, weighting, trim and streamlining — really set an experienced, well-trained diver apart from a novice. They are also universal, in the sense that they will make you a better diver, regardless of what type of diving you enjoy or how long you’ve been participating in our sport. So no matter how many dives you’ve logged, remember to practice, practice, practice.