Dealing with Downcurrents

[Cave Diver]

Got a question....do significant downcurrents provide any visual indication of how large they may be, such as sand being kicked up in them, to let you know what direction to move to get out?

Generally they follow the curve of the wall, just like a waterfall. If you move away from the wall horizontally you should swim out of it. You might be able to move side to side along the wall as well, but it could be hard to determine how wide the "fall" is.

I'd hope anyone doing this type of diving would be comfortable enough to do a blue water ascent away from the wall if necessary.

 

[Prop Joe]

Generally they follow the curve of the wall, just like a waterfall. If you move away from the wall horizontally you should swim out of it. You might be able to move side to side along the wall as well, but it could be hard to determine how wide the "fall" is.

I'd hope anyone doing this type of diving would be comfortable enough to do a blue water ascent away from the wall if necessary.

If stuck in a nasty down welling getting away from the wall is better??? How?
Please explain.
Thanks

 

[ggunn]

If stuck in a nasty down welling getting away from the wall is better??? How?
Please explain.
Thanks

The current interacting with the wall is what is causing the downward flow.

 

[JCR]

Given that vertical currents can occur almost anywhere, are there some southern dive sites that are more likely to have these types of currents? Santa Rosa wall gets mentioned in some reports as does Punta Tunich. Are there others where divers should be especially aware?
thanks
JR

 

[SeaFlea]

Greetings all, I can say that these vertical currents are a reality as I've been in two of them. Years ago, diving with Dive Paradise on one of their EPD dives. Not sure what wall, maybe Santa Rosa, I was pushed down to a depth I'd rather not say in about a minute. It caught me by surprise and my reaction was measured. I was very easy about adding air to my bc and I eventually bottomed out. Venting air on the way back up, stablizing at a proper depth. For years I wasn't sure what had happened until I read about these events on this board.

The second time was last Feb, further down south, past Palancar. I and the rest of our group didn't get pushed down but rather could not swim upwards. I noticed something weird when the water was full of bubbles. bubbles that never rose. we were surrounded in a bath of bubbles. I eyed my depth, kept kicking up, no change. I guess if we hadn't been kicking up we might have been pushed down. We were in this zone for at least 5 min. the group eventually was able to rise, in a controlled ascent, to safety stop zone to end the dive. One of our group was a x-divemaster from Coz and she said she had never seen anything like it.

In any case, be cautious in some of the sites as they can be full of surprises.

Good Dives, SeaFlea.

 

[Dave Dillehay]

To add one more thing to the subject, when one area has horrendous currents, including downward, it may be as calm as a lake 1 mile away. In most all cases the surface will give a good indication of the possibility of down currents. That is, fast moving swirls of water, akin to a incipient whirlpool, is a clear indicator that you should not be diving at that site today. There have been many times that we have abandoned the planned dive site because of that.

As for sites where that may occur, Santa Rosa tops the list but from there south anyplace can have them. As mentioned earlier, such conditions are most prevalent in the spring when a seasonal change takes place, the water warming from 78 F to mid 80s in a month or two.


Dave Dillehay
Aldora Divers

 

[Jax]

Umm . .. If I may ping y'all again . . . are these also an issue in the Playa Del Carmen waters?

 

[Cave Diver]

If stuck in a nasty down welling getting away from the wall is better??? How?
Please explain.
Thanks

Think of current as an "underwater river." It rushes along the bottom, and then when it encounters a wall, it "falls" down it causing a downwelling in the same way a waterfall works on land. Although the current could continue to extend straight out past a wall, it's less likely to and instead will follow the curve down.

This "waterfall" of current could be 10' thick, or it could be 50' thick, but it's likely to be much wider than it is thick. So you're more likely to get out of it quickly by moving away from the wall than moving side to side along the wall. Of course you can always hedge your bet by moving at a diagonal, both away and sideways at the same time.

 

[weaponeer]

A word of warning about strong currents and your regulator exhaust flap - if you find yourself holding on to something for dear life like a reef or any other object and the water flow is rushing by you, do not turn your head perpendicular to the flow to allow the water to pass through your exhaust port. It could turn back the rubber flap and your next breath would be water instead of air. Had this happen to me in a ripping current as I was holding on to a wreck line.

 

[coldwaterlloyd]

Some great input , I was trained when caught in severe down-current to go with it , arch your back and swim away from the wall .
I got into a sever one on Santa Rosa years ago and was able to get out of it relatively quickly following my training . As others have said , just I and my buddy were affected , we rejoined the group and finished our dive , tentatively indeed.