What to do in a down welling/down current?

[crgravitt]

Let me say in advance that I'm not analyzing the SM accident in particular and do not intend to upset anyone with this question. The news of Opal, Gabi and Heath got me thinking again about a question I've never gotten a good answer to - what should you do if caught in a down current? I PM'd DandyDon, who was kind enough to provide me with a very thorough response but he suggested that we get additional thoughts from others. I hope he will not mind that I am pasting part of his reply below - I think he covers some great points and it should be good for getting the discussion going. Thanks to everyone for your thoughts.

Per DandyDon:
There are 4 main approaches available I guess and I don't think as amount of discussion could narrow those down to 1 good answer. Still, we should discuss the risk on the Coz forum more I think as they damned sure happen. I used to not carry my pony on shallow second dives in Coz until I got pulled off the top of a reef and found myself at 100 ft alone wishing I had my pony that I'd left on the boat - just in case...

1: I swam away from the wall to open water to get out, watching my depth closely on computer, but such doesn't bother me. Some are not comfortable with blue water ascents, and you would be swimming away from the only solid help option.

2: Many say to get close to the wall as down current generally are several feet away from one, so you can ascent in no current - but you still have to deal with it when you get to the top. A better place to deal I guess, and you have reef to grab if needed - but I hate grabbing reef even in an emergency.

3: Some say to swim perpendicular or across the current, along the wall, kind of like one might swim out of a rip tide. But then you don't know how wide it is and it'd be difficult to ignore the instinct to want to get up.

4: Some even say that it doesn't hurt to ride them out as it'll turn you lose eventually, but that's the worst to me. As you've heard, extreme depths are possible in these and that'd be a lousy time to learn that your reg doesn't work at 180 ft.

Inflate BC? I did, with my hand staying on the deflater so I could let out the excess quickly as needed to avoid a rapid ascent.

Drop weights? I'd still call that a last resort idea, but if I was getting low on air - I'd at least pull a pocket out and hold it in one hand as I controlled my BC in the other. If I run out of air, or pass out because of doing so, drop the one in my hand at least. A floating drowned person might be revived; a lost downed person has no chance. I didn't think of that on my CESA a couple of years ago but I will if I ever have another.

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[DandyDon]

Haha very good. You copied my response including typos. I don't correct typos in quote either. You only left off the last part of my reply: "Hope that helps some, but I think we should get some other opinions." I'll look forward to others...

 

[Dave Dillehay]

After about 20 years I have come to a pretty good/plausible explanation for the down currents that seem to be most common at Santa Rosa Wall.

When eddies form off the main south to north current, they sometimes push water up on the beach. When that happens the water has to come back down, much the same as rip tides seen by beach goers in heavy surf. When coming back out, that water always chooses the path of least resistance and that is normally between the coral heads. Those gaps become a funnel for the current and that is where the down current is most strong.

Our preferred way to exit a down current is to swim parallel to the wall, usually for 20-30 feet and you are out of it. It is my belief (not experience) that those down currents peter out below 130 ft. Santa Rosa seems to be more prone to down currents and that is because there are many small gaps to funnel the current. Of course that is pretty disconcerting to those who have never experienced it before, but truthfully I don't know of ANYONE who has ever been hurt or lost by one. Indeed we try to make that part of our dive briefing on all Santa Rosa Wall dives and other sites when the current seems strong or capricious.

Dave Dillehay
Aldora Divers

I am not sure that the current does not stay attached to the wall, but I guess it could make a good hand hold if needed.

Dave Dillehay
Aldora Divers

 

[WSOPFAN]

I have a few suggestions.....

1) First of all don't go near or over any wall without at least being advanced certified OR have on the job experience of many many dives like the dive guides do.
2) I know this may seem like an insult and might embarrass some but also, do not get near or over any wall without proper fins that can save you. IMO most of those silly split fin designer goofy colored things they call fins have no propulsion. Get only the best.....the same thing......or a similar design.....of what the Navy Seals use like these:
http://www.alohashoredivers.com/projects/fins/fin8.jpg
Hard rubber long lasting and great for propulsion to get you out of trouble.
3) Don't panic....try close to the wall out from the wall won't hurt to inflate somewhat...some say you might shoot to the top I guess it depends where you are and what you experience.
4) Dropping weights.........that is a tuff one......I think the fact they even teach that as an option is dangerous......It gives a new diver the option of reacting in panic mode and dumping their weights without thinking as we all know they tend to carry extra weight until they are more experienced ...IMO last last resort.
5) How much lift is your BC rated at......ask any professional with years of knowledge why that might be important.
Just my 2 cents for now.......

 

[Cave Diver]

For anyone interested in more info on downwellings, I went through and tagged many of the previous discussions on this.

To access them, go the the Tag Cloud here ---> Tags - ScubaBoard and type in the words downwelling or down current then click the search button.

 

[crgravitt]

Thank you for tagging those discussions, Cave Diver! Good stuff!

 

[jlyle]

I've done many hundreds of dives in Cozumel over the past twenty+ years. Only once did I experience a strong down current and it was on Santa Rosa Wall. The dive guide signaled for everyone to ascend and I noticed that the bubbles were going down instead of up and swirling around me. I glanced at my depth gauge and was surprised to see I was at ninety feet instead of the twenty feet I had been. I didn't inflate my BC nor drop my weights...I simply swam away from the wall and got out of the rip before coming up for a safety stop. So, based on my single experience, swimming perpendicular to the downcurrent was the correct choice. I'm guessing that the downcurrents are like rip tides, narrow rivers of water.

 

[firstdive2005]

I have been in a few of them but mainly north, San Juan area and Barracuda. As Jlyle suggests and did, this is what I was taught to do. I was initially taught how to get out of them in Canada at Vancouver Island in a drysuit. That's a wild ride I tell ya. A cool head needs to prevail. For me I am always watching for the signs of wellings in the areas that look like they could be in. As Dave Dillahey said between heads is a common spot or if you will, valleys in the wall. Kinda like cuts made from a rivers flow in the side of a hill.
But thankfully the down wellings are very rare really in the recreational areas of the park. I think that Santa Rosa has mild ones but they do happen, in the gazillion times I have been on that reef with other divers most dont even notice that they swam out of one. It just seemed they needed a little more effort in a spot is usually the comment I get when I asked if they noticed anything different during their dive.

I certainly dont think anyone ever need fear diving Cozumel be they novice diver or experienced. Make mention of the down wellings to your dive master and they will tend to your concern. My wife is a novice diver. I have no fear of taking her anywhere in the Cozumel dive park except deep areas obviously. She does not want to go deep. Just my two pesos. Good diving to ya. kevin

 

[azscubadude]

For anyone interested in more info on downwellings, I went through and tagged many of the previous discussions on this.

To access them, go the the Tag Cloud here ---> Tags - ScubaBoard and type in the words downwelling or down current then click the search button.

Excellent excellent reading.. thanks for posting the links. I read every post on every page and want to thank ALL the divers for posting their experiences. Truly some wild rides.

I think everyone on this forum should take the time to read the above posts from the search no matter where they plan to dive. Lots of amazing experiences along with lots of differing opinions on what to do, all of them helpful depending on the situation.

Thanks Cave Diver for taking the time to tag the posts.

 

[zendiver001]

Yes, there are downwellings in Coz. I've been in one and have 3 other witnesses.

My wife and I along with 2 other divers (friends) and our DM guide hit one a few years back. I'm pretty sure it was on Santa Rosa wall and I went from 100 to 150fsw in a very short time. I couldn't tell you exactly how short a time, because I was pretty busy.

Both my wife and I are DM's and had buddied each with our less experienced friends for this 'deeper' dive. Our DM guide later stated if he'd known how bad the current on the wall was (the horizontal not vertical) he'd have picked another dive site that day for our less experienced buddies.

We got down to the wall and the horizontal current was rippin'. We dropped to just below the top of the wall flying along parallel to it. We were just getting oriented to the drift when it changed...diagonal, then down. It was the reverse of an uncontrolled ascent and my first indication was a flooded mask which occured as a result of my reg free-flowing. I mask cleared, grabbed my buddy, cranked down the reg flow knob, cleared my mask again and noted that we were now at 130fsw and still dropping. I added air to my BC, my buddy's BC and became painfully aware how slow that is at depth, the air is much thicker I guess, and it didn't seem to be helping much. I was kicking away from the wall out towards the blue and at some point, that seemed to break the fall. I noted 150 on my large number Uwatec computer, and then...we started up. All that air I put in, took effect.

I didn't get us stabilized until 90 ft, adjusting both BC's. And now we were flying horizontal to the wall, but above it. We then made our way down to an outcropping where we could get protected from the current and look for our other divers. This was the point where I came closest to panicking as we'd lost sight of everyone else including my wife and her buddy. I'll admit that I was praying pretty hard, when I saw them fly by 20 feet above us.

That was the end of the dive, as we safety stopped and surfaced with even the local DM a looking a little shook up by the experience. My dive buddy, a delightful young lady with not enough dives for this kind of adventure complained on the boat that it seemed an awful short non-dive until my wife suggested that she look at her analog depth guage with the red pointer at 150. She was completely unaware of what had really occured. Think about that.

My take away point is that it happened very quickly, but it's solveable: 'swim away from the wall'. In hindsight, I'm not sure I had enough lift in that BC to counter it without a weight drop, which I was considering; but getting away from the underwater waterfall stopped it much more safely. And an inexperienced (or narced ) diver might not even know what's happening till it was pretty serious.

Somebody mentioned a rip current, and that's exactly what it is, only vertical.

In over 1000 dives over 40 years, that was the closest I think I've been to 'out of control'. But I would know exactly what to do now; and I don't worry about it when I'm diving some of the best drift diving in the world, in Cozumel. If I were a local DM, I'd let people know what to do without scaring them.

Ed