Dealing with current

[billt4sf]

We have about 150 -200 dives so we're still learning -- and one thing I want to learn more about is how to deal with current. Of the problem dives we have had (maybe 10 - 20?) more than half have to do with current. Here is one such dive:

How I almost drowned -- twice

But that's just the worst one. Thank God.

Are there any courses that help one with current? Any exercises we could do? Maybe some specific practice we could do with an instructor or in the pool?

We're OK (and enjoy) drift diving. I guess our problems come about when we can't just drift. Surge isn't the nicest thing either. One thing I know from examining myself is that I do get anxious when there is current -- that would be one thing to try to change.

Any other hints?

Thanks in advance.

Bill & Emily

 

[dmaziuk]

FWIW pool records for fin swimming are on the order of 3 m/s or about 9 mph or slightly less than 8 knots. Unless my mental arithmetics is off. That's olympic-level athletes in monofin, lycra, no bulky gear, and pretty short distances. I'd say if you're in a current that's over 1/5th of that, the only thing you can realistically do is "relax and try to enjoy it" -- you may be able to kick against a 1-2 mph, but you'll be OOG very quickly. I.e. I'd be surprised if there's any physical exercises that would help with the kind of current you've described.

 

[Jim Lapenta]

Depends on the dive. On some wrecks current is dealt with by staying on the lee side sheltered from it. Surge can be a biatch, and if it's bad enough I just call the dive. General rule is to start the dive by swimming into the current. This allows it to take you back to your starting point with less air. I would never start a current, non drift dive by trying to swim with it or parallel to it. Very good way to end up in Timbuktu and be the inspiration for the next Open Water movie. Most people can deal with 1/2 knot or so. More than that and you start to see serious fatigue, over breathing, leg cramping, and worse. I was on the Duane when the current went from very mild to better than 2 knots on the ascent line. Coming off would have been a serious problem as it also managed to wrap the granny line from the bow to the stern in the free wheeling prop that was in neutral. Better to not do the dive.

 

[The Chairman]

Currents are problematic for most divers. Jim gave a couple good ones. Let me give you my list. There will be some repeats:

• Start your dive swimming into the current. The boat tether/anchor line is almost always your guide. IOW, boats usually face into the current, unless there's a bodacious wind. Listen to your dive briefing for clues on this. Turn your dive when you used a third of your air and drift back. Use any remaining NDL and air under the boat.
• Stay low and in the valleys. Use the natural cover that slows and blocks the current. Fish do this all the time and you can see them stacked behind rocks and other breakwaters.
• Go slow. No, slower than that. Work at finding and looking at the cool stuff, not at covering lots of ground. You're still probably going too fast.
• Pull and glide. On most reefs there is a lot of dead rock. It's OK to use dead rock as a finger hold and gently pull yourself along. You'll have to be low to the reef to do this. Remember to go slow and don't accidentally grab a stone fish. Yeah, you're still going too fast!
• Carry a sausage! Learn how to deploy it from depth. If you're swept away, or even think you've been swept away, send it up so the boat can see it early! Carrying a Nautilus Life Line is a great idea.

Currents on wrecks:

• Use the down line efficiently. DON'T KICK while on the down line. Just pull yourself down, but don't get winded. I move pretty fast down the line as I want to get out of the current. It's the only time I opt for speed, but I'm used to it. Few keep up and I don't mind waiting at the bottom. I usually tag the down line with a cookie or a ribbon if there's more than one on a wreck.
• Stay on the protected side (the lee of the current). That means, let the wreck block the current for you. if you still have current, remember to swim into the current first. Again, only use a third of your air going out and drift back to your cookie or ribbon on the second third. Wrecks are usually deep, so keep a third to ascend on.
• STAY ON THE WRECK!!! If you dealt with a lot of current going down, don't be fooled by the slack current when you're on the protected side (lee). Critters are far better equipped to deal with the current than you are. Swimming off the wreck by ten or fifteen feet to get a pic of that turtle or pretty fishie just might mean you'll get on Mr Toad's Wild Ocean Ride. They'll swim easily back while you're burning through air and are still being swept away.
• Carry a sausage! Learn how to deploy it from depth. If you get blown off the wreck, deploy it ASAP and relax. Do your stops and try not to blow through your air. Again, carrying a Nautilus Life Line is a great idea.

 

[dumpsterDiver]

We dive in significant current often in our local waters. We generally drift into wrecks, but once on a particular reef or wreck, we may want to be stationary. There are a lot of tricks to dealing with current.

There is no substitute for physical strength and endurance. There is no substitute for good powerful fins.

The main theme is probably that you are weak and can not fight currents. You (as all scuba divers) are pretty terrible at moving against a current - even the smallest fish can do a better job. So once you realize that you can not really swim against any significant current for any significant time (without blowing through an incredible amount of air and probably getting a CO2 headache) you have to be smart.

If you MUST move against a current - crawl - hold onto the wreck or dead portions of a reef. You can literally hold yourself by one finger easier than you can swim against the same current and hold position. Try to get your body down close to the reef or wreck, the velocity drops off as you get within a foot or so of the bottom.

Think like a bird... you never see a bird perched with his back to the wind... when you stop to look at somehting, spin around and keep you head into the current - it is more natural, more streamlied and allows you to actually swim against it. Try holding onto something with your butt and fins into the current, it will try to flip you over.

If crawling along the bottom, you want to probably dump all air from the BC and be as heavy as possible - this gives you stability in the current.

Watch the fish, they tend to congregate in eddies and often in still areas behind reefs or wrecks.. not always, but pay attention to the fish.. they too will almost always have their face to the wind and if they are swimming hard, there is current, if they are resting, not much in that particular area.

Duck behind the reef and wreck, avoid the current - it makes a huge difference. IF you do have to move against a current (assuming a reasonable distance and a reasonable current) do NOT swim slow! Swim FAST! Swim at maybe 70 or 90% of your capacity, shoot across or through the current and find another hand hold. if you try to swim 30 feet slow and steady against a current, you may end up kicking away for 90 seconds and getting almost no where. this will waste a lot more air and effort than a quick sprint.

This video at around 5:15 shows my 14 yr old son dealing with a pretty strong current, when he goes from one hand hold to another one up current; he has to follow me and traverse a short open area with no real hand hold.. So he follows my lead and sprints the short distance in a few seconds. The point is to conserve energy, use power when you need to, but realize that you can not swim hard for long at all.

Surge is another specialty. It can be very strong. You definitely do not want to fight surge. You cling to the bottom, allow the surge to pass over you and then on the back flow, you release and kick and glide for the duration and find another hand hold. If you miss and go backwards, it is often better to just allow yourself to be propelled backwards, than try to kick super hard and fight the surge. You can actually ride a surge in or out, if you are smart and ride the energy and avoid fighting it. I don't have any decent examples of surge diving.

 

[CuzzA]

I'll add, you may want to consider long free dive fins. The performance is night and day compared to a standard scuba fin. Do some research though as some long fins can tire you quickly while others are designed more for the long haul.

 

[clownfishsydney]

First, get to know the "real" strength of a current. Most people overestimate the speed of a current. For example, they say they dived in a 4 knot current (not a drift dive). This is impossible, the maximum speed that you can even make a very slow headway against is about 2 knots. Even then you will be soon exhausted. If a current is over 1 knot, consider not diving. Figure out how to work it out. If you watch some bubbles float past your boat, you can work it out. If you are on a 10 metre boat (33 feet) and a bubble takes 20 seconds to pass from the front of the boat to the stern, then you have just under 1 knot. That is, about 1 second per 1 metre (3.3 feet) is 1 knot.

You can also get in front of a wreck or a large rock and you will find that you can hang there with little effort. This is like what dolphins do when riding a bow wave of a boat. It really does work. Of course, you generally have to swim into the current to get to that spot, so lots of what was mentioned above will help.

Also, get to know how strong a current is by looking around you on the surface. Check how quick the froth or bubbles are moving compared to the boat, check what the mermaid and dive ladder are doing. On my boat, if the ladder is lying flat on the surface, there is no way we are diving. If it is at an angle of more than 45 degrees from horizontal, it is easily diveable, in between, much harder. The same goes for our deco line (we hang a 5 kg weight off the starboard stern bollard which goes to 14 metres). If it is hanging back much more than 33 degrees from the vertical, we do not dive.

In the above cases it may be that the current does not go all the way to the bottom, but even if it does not, this sort of current is so strong that you would be exhausted by the time you got down and also used a huge amount of air.

We have rescued many a diver off Sydney who has drifted away from their boat (charter mostly) when they should not have dived.

 

[Rusty Roo]

don't fight it go with the flow.

 

[nolatom]

Agree with all comments above. If you are diving in the afternoon in current, bring a nighttime strobe just in case you get lost and need to be seen. Also a signalling mirror for daytime.

If you absolutely have to go against the strong current and you are on a sandy bottom, use whatever you can dig into it as a "pull and glide" (though it'll be mostly pulling and very little gliding). Dive shears in one fist and knife in the other fist, can move you like climbing a horizontal ladder with your arms, and might get you to that anchor line or wreck or rock or other blessed object, when no amount of swimming could. You need semi-negative buoyancy to help this work. And the current is probably going to be less swift right on the bottom than higher up.

 

[REVAN]

We have about 150 -200 dives so we're still learning -- and one thing I want to learn more about is how to deal with current. Of the problem dives we have had (maybe 10 - 20?) more than half have to do with current. Here is one such dive:

How I almost drowned -- twice

But that's just the worst one. Thank God.

Are there any courses that help one with current? Any exercises we could do? Maybe some specific practice we could do with an instructor or in the pool?

We're OK (and enjoy) drift diving. I guess our problems come about when we can't just drift. Surge isn't the nicest thing either. One thing I know from examining myself is that I do get anxious when there is current -- that would be one thing to try to change.

Any other hints?

Thanks in advance.

Bill & Emily

Get long blade fiberglass fins with the right stiffness to match your leg strength and learn to kick them properly. Practice! Good technique is critical to hydrodynamics, efficiency and speed in the water. Also, streamline your dive kit and get your weight and trim right. These things will make a big difference in how well you can swim and deal with currents.

Leave the pony bottle in the gear bag and use your SAC predictions and pressure gauge to execute the dive. The last thing you want to do in strong current is booger up your hydrodynamics with extra gear. Use enough margin on your depths and times that you don't need the pony bottle. This is just a restriction that a strong current site will impose on the dive plan. If not, this is a technical dive and you will need a technical plan to execute, but I get the impression that is not your gig.

Most will tell you that it is futile to try to be faster in the water. They are wrong. For whatever reasons, swimming performance for scuba divers has become a lost art. Few actually practice it these days, and no one is actively teaching how to do it that I know of. Few divers are even aware what can be done and many divers actively resist the concept of improving hydrodynamics, thinking that it makes no difference. But, there are significant things that can be done to make yourself more robust against unexpected current situations.

Also, take the other advice that has already been given on how to try to stay out of the current as much as possible. If it doesn't work for some reason, you will be better prepared to do whatever you need to do to swim out of it if you have already addressed swimming performance. Better to be prepared than to be sorry.