tWO DIVERS PULLED DOWN 64M

[ScubaSarus]

Wow Holy downcurrent. Another reason to use as little weight as possible although I don't know the power of these things and if they ditched their weights. Amazing what the ocean can do.

 

[nicka]

Last year a group of divers got pulled down near cook stait 60m+ all were drift diving tied together ,3 died with one body never recovered!.

 

[Diver0001]

A Wellington Free Ambulance paramedic was winched on to the launch, in 40km/h winds and two-metre swells.

Yikes! that's a Force 6. Aside from what happened under water I have to wonder what the heck they were doing out there to start with ....

R..

 

[Santa]

I gotta tell you - this is the part of diving that (probably irrationally) scares me the most. The thought of getting caught in a downswelling like this just gives me the willies.

With you all the way there. My old instructor used to be more afraid of sudden upwellings. The idea of being propelled upwards near the end of a 40-50 metre dive is not really my idea of a great day at the races either.

Do you think it's psychological that being pulled down seems worse than being pushed up (doing the ol' Pepsi dance)? Or could it be argued that there are some added dangers due to gas toxicity, tissue loading, psychological factors, air con and distance to surface?

 

[Web Monkey]

It looks like Physics wins again.

I went through the original thread, and it looks like the answer is to swim up and away from the downcurrent, and inflate your BC until the air is blowing out the overpressure valve, if necessary.

Also an interesting point I hadn't really thought of is: that if your BC is full and you're still going down, keep inflating, since as you decend the air compresses, and it's no longer full anymore.

A liftbag will also help, although blowing a liftbag on a reel, while trying to inflate your BC and swim out of a downcurrent sounds challanging, to say the least.

The sounds like a good case for not using the low-buoyancy "Travel BCs" that seem to be popular on vacations.

Terry

See the following thread:

http://www.scubaboard.com/showthread.php?t=48956&highlight=downcurrent

Seadeuce

 

[Diver0001]

A liftbag will also help, although blowing a liftbag on a reel, while trying to inflate your BC and swim out of a downcurrent sounds challanging, to say the least.

Yeah, this, in my mind, must be an urban myth. If you're in a down current bad enough to make you desperate enough to reach for your blob then it's not going to go up even if you did ... somehow...through some miracle.... manage to get air into it. Even bubbles will sink in a bad enough downcurrent.

The way I see it, the only good fumbling around with your blob is going to do you in that situation is if it snags on something.

R..

 

[Azza]

Yikes! that's a Force 6. Aside from what happened under water I have to wonder what the heck they were doing out there to start with ....

R..

Dude, thats what us Cook Strait divers dive in everyday just about. Its a harsh piece of water being an 11 Nautical Mile gap in the otherwise 1000 mile landmass of New Zealand, when it's high tide at one end it's low tide at the other.

On some dive sites slack tide lasts about 5 minutes so the dive has to be timed right. If it is timed right you can deal with a 1-3 knot current, if not you could be dealing with a 4-7 knot current.

We try to minimise the danger by only diving at certain sites on certain tides.

There are also places we dive that we do not take customers unless we know them and their diving ability intimately. This usually means they come on our "boys trips", meaning they are not a paid charter but our time out for personal dives.

Awash rock, where these guys got dragged down, is a rock that just breaches the surface at low tide and rises up from 120 metres plus. Its a great spot but unpredictable.

Forget about talk of blowing a lift bag, I have been caught in these currents. You need to see them before you hit them, which is possible if you know the area, and avoid them.
All you can do if you get caught is blow your BCD and try to swim sideways out of the down current or wait until it spits you out.

 

[Scuba Stu]

You need to see them before you hit them, which is possible if you know the area, and avoid them.

Just curious as to how you see downswells other then aquatic life being dragged down? Can you see downward turbulance in the water column?

 

[String]

May be they were diving without local knowledge (DM) or a local

or maybe those conditions did not make that site undiveable.

Swell doesnt always stop a dive, wind doesnt always stop a dive. Different sites have different suitability to conditions.

25kt winds may make it uncomfortable but not impossible.

 

[cowdog77]

RM: It was gracious of you to respond to this post with info on downcurrents even tho there have been other threads dealing with this issue. Much appreciated ---thank you ! ~