Improving air use in currents

[Iralub]

I'm wondering what would be most effective ways to improve my air use in currents?

By way of background, I'm a fairly novice diver, with only 40 dives. My air use in normal conditions tends to be very good. Diving a regular 12L tank, I usually come back with close to half a tank at the end of permitted dive duration or when at least one person in the same dive group is down to 50 bar. This is probably due to being very small rather than any particular achievement of mine. I also seem to be able to breathe very slowly and deeply underwater. I am not superfit and because of my size I struggle with the size and weight of a 12L tank, especially on entries and exits.

On a liveaboard I did earlier this year I was given a 10L tank, which made dealing with gear much more pleasant. I was still coming back with more air than others, except the instructor, and was enjoying the dives much more. Recently, I was diving on 8L tanks on reasonably shallow dives (<20m) and was coming back with just a little less air than most others on 12L tanks and a little more than some. I was much more comfortable both in and out of the water and less tired after the dives.

Because my diving experience is so much more pleasant with the small tanks, I'd like to use smaller tanks in the future when they are available, however I am worried about limiting the group's bottom time if I am the first to get to the turn around air point. In normal conditions it doesn't seem to be an issue, but as soon as there is a current, my air use goes up pretty dramatically. I don't know that it goes up more than others, but if I'm on a smaller tank, I'll be burning through air pretty quickly.

So I'm hoping for a way to improve air use in currents to minimise these issues. Are there any exercises that I can do? I've been trying to do more fast/power walking (my knees don't seem to like running) but am not sure whether it is the right thing. I can't figure out whether it is a matter of leg muscle strength or aerobic fitness or something else? I'd be grateful for any ideas.

(All help appreciated, but please don't say "don't dive in a guided group", I know it is a possibility for the future, but I'm not confident enough yet!).

 

[Hickdive]

Strangely enough, beyond a certain level, aerobic fitness is actually counter-productive if you want to minimise air consumption. I'm not saying don't be fit but the ultra-fit seem to chug through air most rapidly.

That said the #1 tip for reducing gas consumption is streamlining your equipment and #2 is ensuring you have the flattest trim possible in the water. #3 which, if you crack #1 and #2 is easy, is getting your buoyancy spot on.

Get those three right and your resistance to the water flow and tendency to fin against buoyancy will drop dramatically and consequently you will have to work less and thus use less gas.

Another tip is to change your finning technique. Instead of using one that principally causes water to be pushed down you could use a stroke that causes water to be pushed back.

Finally - go diving, lots. Nothing improves air consumption more than actually going diving regularly.

 

[tomfcrist]

If you are diving in strong current, the only way to truly prevent blowing through gas is to either dive on the leeward side of structure(out of the current) or do a drift dive.

 

[Iralub]

That said the #1 tip for reducing gas consumption is streamlining your equipment and #2 is ensuring you have the flattest trim possible in the water. #3 which, if you crack #1 and #2 is easy, is getting your buoyancy spot on.

Get those three right and your resistance to the water flow and tendency to fin against buoyancy will drop dramatically and consequently you will have to work less and thus use less gas.

Another tip is to change your finning technique. Instead of using one that principally causes water to be pushed down you could use a stroke that causes water to be pushed back.

I've been thinking of doing the peak performance buoyancy course - should probably go and do it

What would be a finning technique/style that primarily pushes the water back? Sorry if this is a stupid question.

 

[highdesert]

Strangely enough, beyond a certain level, aerobic fitness is actually counter-productive if you want to minimise air consumption. I'm not saying don't be fit but the ultra-fit seem to chug through air most rapidly.

I've seen this theory posted here before, and if there's anything to it, it certainly is "Strangely enough ...". Can you post a link to any articles that back this up?

 

[Hickdive]

I've seen this theory posted here before, and if there's anything to it, it certainly is "Strangely enough ...". Can you post a link to any articles that back this up?

No, it is an anecdote. Similarly it is also anecdotal that I know divers who smoke like chimneys who sip air and can outlast anyone else I know on any given cylinder size.

---------- Post added November 10th, 2014 at 12:48 PM ----------

I've been thinking of doing the peak performance buoyancy course - should probably go and do it

What would be a finning technique/style that primarily pushes the water back? Sorry if this is a stupid question.

Try frog kicking, there are lots of video guides on doing it, here's just one;

[video=youtube;DoJ2BhS6Bis]https://www.youtube.com/watch?v=DoJ2BhS6Bis[/video]

 

[MXGratefulDiver]

Best way to reduce air consumption in current is to pay attention to your trim. Think of current like the wind ... you reduce wind resistance by minimizing the amount of surface area that's exposed to the wind. Same goes for current. If you're out of trim and kicking into the current, you're displacing a lot more water than you would be if you were in proper trim. Water's heavy stuff, and requires a lot of work to move through. The more water you have to displace, the harder you work ... and the harder you work, the faster you'll use up your air.

Point your head into the current ... keep your body horizontal ... keep your hands in close to your body (definitely don't wave them around) ... and eliminate any equipment danglies ... that's the best way to reduce the amount of effort it takes to move around in current, and therefore reduce your air consumption in those conditions ...

... Bob (Grateful Diver)

 

[divin'dog]

If you're diving in a current, try not to fight the current. Obvious advice but many divers still "fight" the current. Try to be relaxed in the current. It is going to take you where it wants but you can slow/reduce the force it has on you.

As said above in other posts, it starts with buoyancy, trim, weighting and streamlining... All the standard/basic skills you need to get under control to help being better in currents. The next thing on the list is knowing how to slip through a current if you intend to swim against it. Use the ground cover (large rocks, boulders, plants, depressions in the bottom) to hide in and behind in order to minimize the current's effect. You need to use whatever terrain you have to your advantage. Also hugging the bottom or a wall when there is little to no cover (wide flat area) is a big help but you will need to have good basic skills. There are pools of eddies behind the uneven terrain where it is calm. Use them to your advantage. Sometimes you will need to zig-zag along the bottom going from rock to rock... If you see some fish on the dive, you will see how they manage to stay out of the current or minimize its effect.

If you have an opportunity while diving in a current (hopefully an easy current), play with the current, ducking behind rocks and just hanging. Peer over the rock (if it's big enough to hide behind) slipping into and out of the current. Find the eddies in the terrain. It's not that hard to get the hang of it. If you've ever seen an expert paddle a canoe up a swift running river, hiding around the bends, going back and forth to hit the eddies, then you know what I mean.

 

[tbone1004]

modified breast stroke kick, or frog kick is the best forward propulsion technique in that situation, it requires relatively large stiff fins for greatest effect, and serious leg strength to move quickly, but it is much more efficient than floppy or split fins. Note, White Sharks, toothed whales, etc all have stiff fins, little frilly reef fish don't, and they don't swim particularly fast and don't do so hot in currents. Make like shark, not like angelfish. There is an efficiency thing with navigating the terrain, but you can also draft behind other people, being in the back in current is sometimes advantageous, especially if you are up close and the guy in front of you is big. Other than that it is making sure you are truly diving flat, and have good buoyancy so the only thing you are fighting is the current, if you are overweighted *the norm*, then you tend to have to dive slightly head up to kick not only against the water in the horizontal direction, but also fighting against the buoyancy problems you have, this trim profile is inefficient in calm water making you look like a frog hopping, going up and forward instead of just forward, but it increases your frontal surface area immensely in current and that's just bad news.

Fish and aquatic mammalia are masters of efficiency underwater, learn from them.

 

[theskull]

Good tips above. I will add to be aware of your breathing at all times, especially when exerting effort or feeling anxious, such as kicking against the current. Be aware of every breath, keep control of it, and try not to work so hard that you end up panting.

theskull