Types of currents and how to deal with them

[alan_lee]

Hi everyone! Just wanted to find out what are the different sort of currents that are encountered, and what are the strategies to get out of them. I can think of a couple like surge, unidirection, upward, downward, whirlpool... are there others?

In terms of getting out of the currents, for surge, I'd usually try to take cover when the currents pushing me, and then fin when it's pulling. For unidirection, I try to either swim perpendicular to it, or zig-zagging.

Would appreciate your inputs as well as any corrections should I get my facts and strategies wrong.

Cheers!

 

[sambolino44]

Get out of them? You don't get out of them; you go with them or you avoid them in the first place. I've done several drift dives. Currents, unless they're really slow, usually go way faster than you can swim, so it makes no sense to try and fight it. The best thing is to plan, plan, plan. And check out the site before you get in the water. If you find yourself fighting a current, you will lose. I guess the only thing is to go at a right angle to it, if you can't just let it carry you along for some reason. I have experienced a few vertical currents, and that was disconcerting, but luckily they didn't carry very far or fast. I'm lucky where I live there is a lot of info available online about local tides and currents. Not every place has that.

 

[Nomad]

I once stood on a rock outcrop on the west side of Oahu and watched the water move in and out. I stood on the edge of a cliff. When a wave came in, the ocean water would splash my feet. When the waves rolled out, I watched the water level drop 40 feet. Seriously, 40 feet...

I realized in that instant that I may never again witness such raw power.

Additionally, I realized that there is no way to fight water currents. They weigh more than me. They are stronger than me. They can last longer than I can.

From the perspective of a diver, hydrostatic pressure is unstoppable.

You don't fight the power of the ocean, you learn to use it.

So with that said...

If you find yourself in a current that runs parallel to shore, you swim towards shore, in a downstream/diagonal pattern.

If you find yourself in a current that runs perpendicular to shore (a rip tide), again, swim towards shore, in a downstream/diagonal pattern. In all instances, use constant, non-exhaustive efforts.

In rivers, I have encountered whirlpools and currents that push and hold me down (I forget what that is called). Remember, unless the waterflow moves into an underground tunnel, you will eventually be pushed to the surface. Eventually, the hydrostatic pressure will win. The key is to maintain air supply (hold your breath when free diving, or conserve air if scuba diving) until that occurs. In river diving, let the water win. If you are using air, relax and let the pressure move you. If you are skin diving, hold your breathe, follow the current, and work for the surface.

If you are ocean diving and you find yourself being swept out to sea, deploy a die pack, and pray. Did I mention, bring a die pack?

Most importantly, know the water conditions before you get wet. If conditions are dangerous, stay dry, and live to dive another day. It is always better to be watching TV, wishing you could dive, then to be sitting in the ocean, wishing you could watch TV.

Does that help? Or am I just rambling on a tangent?

 

[SlowRain]

Mark Spitz...on a good day, with a tailwind and a downhill start would not be able to swim against a current of 1.5 knots and make headway. As the above stated...if you are open ocean and you being swept...you are NOT going to be able swim against even a moderate current. To do so is only going to exhaust you.

If you run into an undertow/riptide....swim perpendicular to the flow...you will still be pulled, but by going across the flow eventually you will get out...open ocean is another matter. That is a good reason to carry a safety sausage, whistle, signal mirror and even a strobe (open ocean diving I have all 4 on me). A dye pack is a good idea, but be careful about deploying it....best to throw it out when you have aircraft in the area....because using it in even moderate seas is going to break up the slick fairly quickly.

To give you an idea of how powerful water can be....we used to do current runs when I lived in the Seattle area. Tidal exchanges there can get to 12' of water. There is a place referred to as Agate Pass. It is the channel that runs between Bainbridge Island and the Olympic Penninsula. The first time I got to do that run, I had geared up except for fins, and proceeded to only go far enough where there was about 2' of water and when I sat down to put the fins on....the current was actually pulling me along the bottom...in 2 feet of water.

As someone else said...know what the conditions are....and learn to use the current to your advantage...or avoid it.

 

[DanLVolker]

Mark Spitz...on a good day, with a tailwind and a downhill start would not be able to swim against a current of 1.5 knots and make headway. As the above stated...if you are open ocean and you being swept...you are NOT going to be able swim against even a moderate current. To do so is only going to exhaust you.

If you run into an undertow/riptide....swim perpendicular to the flow...you will still be pulled, but by going across the flow eventually you will get out...open ocean is another matter. That is a good reason to carry a safety sausage, whistle, signal mirror and even a strobe (open ocean diving I have all 4 on me). A dye pack is a good idea, but be careful about deploying it....best to throw it out when you have aircraft in the area....because using it in even moderate seas is going to break up the slick fairly quickly.

To give you an idea of how powerful water can be....we used to do current runs when I lived in the Seattle area. Tidal exchanges there can get to 12' of water. There is a place referred to as Agate Pass. It is the channel that runs between Bainbridge Island and the Olympic Penninsula. The first time I got to do that run, I had geared up except for fins, and proceeded to only go far enough where there was about 2' of water and when I sat down to put the fins on....the current was actually pulling along the bottom...in 2 feet of water.

As someone else said...know what the conditions are....and learn to use the current to your advantage...or avoid it.

Another option on a beach diving scenario, is "watching" the bottom moving under you from the beginning---if you can see you are getting transported fast--too fast for controlling your position by swimming, then while you still have nearly a full scuba tank, you dump all your air from your bc--get negative, and go hand over hand on the bottom toward shore. In most sandy beach areas, there will be ripples in the sand that can assist you in orientation--they run perpendicular to the main currents, so they can sometimes help--the diver needs a compass to be sure. You can dig your hands in to the sand, and pull along against a huge current -- if you can get negative enough.
Back in the early 80's, when I was doing dives from the jetty off of the Lake Worth Inlet, we would often expereince currents over 5 mph at full rip...this could be beaten with the "hand over hand" technique, but to plan a dive to do this on purpose would be very stupid....and of course, we were stupid pretty often back then

Dan

 

[highdesert]

Get out of them? You don't get out of them; you go with them or you avoid them in the first place.

This is a helpful advice in lateral currents, but IMHO it's one that shouldn't be adhered to across the board. In areas of the world where groups of islands, in conjunction with significant tidal ranges, can cause ripping currents in any conceiveable direction, just "going with" the current can mean you might never be seen again.

Possibly the most dangerous is a downwelling current, which can carry a diver hundreds of feet down in a few handfuls of seconds. I've never had the (dis)pleasure of being in one this extreme, but this is a case where you consider reaching for the elevator button on your BC and get as close to the surrounding topograpy as possible, allowing the current to pass over you.

We were faced with a very strong upcurrent during one dive at Wakatobi. While you're probably not going to disappear, the danger here is being carried to the surface way faster than a normal, safe ascent rate. Forget trying a safety stop. In this case we were along a wall, and blew our BC's and tucked in close to the wall while finning almost straight down to control ourselves.

 

[BuoyantC]

As Dan Volker stated about pulling along the bottom, you really can easily pull yourself along in a current you can't possibly swim against.

Most of our shore dive sites here are through cuts in a shallow reef edge. These have rip currents varying from mild to extreme. There are usually permanent ropes at popular spots, but occasionally they will break making it necessary to hand over hand your way in. It always amazes me that I can hold myself with one finger against a current I can't fin against.

D.C.C.

 

[SlowRain]

As Dan Volker stated about pulling along the bottom, you really can easily pull yourself along in a current you can't possibly swim against.

Most of our shore dive sites here are through cuts in a shallow reef edge. These have rip currents varying from mild to extreme. There are usually permanent ropes at popular spots, but occasionally they will break making it necessary to hand over hand your way in. It always amazes me that I can hold myself with one finger against a current I can't fin against.

D.C.C.

As the two stated above...certainly there is the option of pulling yourself along the bottom (umm as long as the bottom is within reach) and..most dive boats have a line off the back of the boat running 200+ feet so divers have something to grab onto to pull themselves to the boat...however if you are in a situation where the bottom is too deep, or you are nearly out of air, have a plan B.

 

[cmburch]

That is a good reason to carry a safety sausage, whistle, signal mirror and even a strobe (open ocean diving I have all 4 on me). A dye pack is a good idea, but be careful about deploying it....best to throw it out when you have aircraft in the area....because using it in even moderate seas is going to break up the slick fairly quickly.

I need to rethink and plan better. I have swam out of currents, swam against currents, pulled myself along the bottom 10-35' deep as well as along bull kelp or rocks to get out of currents or back into shore. I have never thought about what I would do if I tired and got carried out to sea.

 

[Buoyant1]

When I was in the Keys last November, there was a bit of surge on most of my dives, some worse than others, I learned from watching the fish, they waited for the surge to subside, then moved forward, then rested when the surge picked up, and when the surge subsided again they moved...it worked pretty well and was great advice from the DM..I had a much longer dive on my second dive by using this method. Fish are the experts!