Diving in Strong Current or Downcurrent

[northernone]

The best I've got is stay close enough to hang on when necessary, face straight into the current. My bcd can only provide 20-40lb lift and my fins 10-20lb. So at best that's 60lb. I can hang on upwards of 200lbs provided I have a two hand grip. I certainly don't want to be trying to deploy a dsmb or lift bag in those conditions.

Diving Galapagos I didn't encounter significant currents but still were glad for rocks nearby as a comfort . Same goes for the down wellings in cozumel. I've been in one where hard finning and a 45lb bcd was unable to arrest my descent last year so I've since learned to stay close to the wall.

Regarding disorientation, if the bubbles don't go up, trust the bright spot to be up, even with no mask.

Swim across the current to a rock, facing the flow so you don't lose a mask or reg ( inhaling strongly through the nose nearly assures you won't lose a mask).

Too bad reef hooks are out of fashion in the Galapagos.

Enjoy,
Cameron

 

[gabyintheworld]

The best I've got is stay close enough to hang on when necessary, face straight into the current. My bcd can only provide 20-40lb lift and my fins 10-20lb. So at best that's 60lb. I can hang on upwards of 200lbs provided I have a two hand grip. I certainly don't want to be trying to deploy a dsmb or lift bag in those conditions.

Diving Galapagos I didn't encounter significant currents but still were glad for rocks nearby as a comfort . Same goes for the down wellings in cozumel. I've been in one where hard finning and a 45lb bcd was unable to arrest my descent last year so I've since learned to stay close to the wall.

Swim across the current to a rock, facing the flow so you don't lose a mask or reg ( inhaling strongly through the nose nearly assures you won't lose a mask).

Too bad reef hooks are out of fashion in the Galapagos.

Enjoy,
Cameron

Thanks! My only experience with strong current was at Cauldron in Komodo National Park, Indonesia, using a reef hook, so yeah I definitely understand you!

 

[Kevrumbo]

The toughest dilemma for Nitrox Divers is the Downcurrent Scenario. Obviously you cannot fight & kick going against it expecting to make an escape while it carries you deeper & deeper approaching and going past Nitrox Max Operating Depth (MOD).

Do not use Nitrox 32 if you know beforehand that you will be at a divesite with downcurrents. Otherwise you may be approaching the MOD limit 39m/130' if the downcurrent forces you that deep. In that case you have to ride it out because exerting yourself any further into CO2 retention/Hypercapnia will only increase the chances of oxygen toxicity and convulsions at that depth and deeper.

If you are carried over the wall into blue water (i.g. missed chance of hanging-on or climbing back up the rock/coral wall), try riding with the flow, but finning through and finding the boundary edge of the downcurrent column where it starts to slacken, and then pick that moment to kick hard & fast to escape the flow. Be aware though this may carry you deep past recreational depths, but it should not be an added problem working a controlled ascent back up with minimal mandatory decompression obligation -provided that you have plenty of breathing gas margin to begin with.

The most likely & harshest situation near the end of a dive to be caught in a Downcurrent -if you're running low on breathing gas (air or nitrox), inflate your BCD and kick hard away orthogonal to the downcurrent flow, and hopefully you just happened to pick the right moment & direction to quickly bust through the boundary edge of the downcurrent column into slack water. And if you do escape, remember to deflate-control your BCD or else you'll rocket to the surface.

Absolute last draconian resort and toughest choice to make a downcurrent escape: inflate BCD and drop weights . . .essentially in this case you're out of time and air.

In summary, the strategy is to find the slack edge of the Downcurrent column without physically exhausting yourself into Hypercapnia especially if breathing Nitrox 32. The caveat though is whether you have enough breathing gas supply to be carried deep, and to cover the ascent to the surface along with any computer mandated deco stops.

 

[gabyintheworld]

This is literally my worst case scenario. I have been reviewing emergency ascent protocols in case this very situation happens.

The toughest dilemma for Nitrox Divers is the Downcurrent Scenario. Obviously you cannot fight & kick going against it expecting to make an escape while it carries you deeper & deeper approaching and going past Nitrox Max Operating Depth (MOD).

Do not use Nitrox 32 if you know beforehand that you will be at a divesite with downcurrents. Otherwise you may be approaching the MOD limit 39m/130' if the downcurrent forces you that deep. In that case you have to ride it out because exerting yourself any further into CO2 retention/Hypercapnia will only increase the chances of oxygen toxicity and convulsions at that depth and deeper.

If you are carried over the wall into blue water (i.g. missed chance of hanging-on or climbing back up the rock/coral wall), try riding with the flow, but finning through and finding the boundary edge of the downcurrent column where it starts to slacken, and then pick that moment to kick hard & fast to escape the flow. Be aware though this may carry you deep past recreational depths, but it should not be an added problem working a controlled ascent back up with minimal mandatory decompression obligation -provided that you have plenty of breathing gas margin to begin with.

The most likely & harshest situation near the end of a dive to be caught in a Downcurrent -if you're running low on breathing gas (air or nitrox), inflate your BCD and kick hard away perpendicular to the downcurrent flow, and hopefully you just happened to pick the right moment & direction to quickly bust through the boundary edge of the downcurrent column into slack water. And if you do escape, remember to deflate-control your BCD or else you'll rocket to the surface.

Absolute last draconian resort and toughest choice to make a downcurrent escape: inflate BCD and drop weights . . .essentially in this case you're out of time and air.

In summary, the strategy is to find the slack edge of the Downcurrent column without physically exhausting yourself into Hypercapnia especially if breathing Nitrox 32. The caveat though is whether you have enough breathing gas supply to be carried deep, and to cover the ascent to the surface along with any computer mandated deco stops.

has lit

 

[cipherbreak]

This is literally my worst case scenario. I have been reviewing emergency ascent protocols in case this very situation happens.

has lit

When downcurrents are a concern and the hard bottom exceeds the EANx MOD, I dive air.

 

[Kevrumbo]

This is literally my worst case scenario. I have been reviewing emergency ascent protocols in case this very situation happens. . .

Best prevention is to be informed through Pre-Dive Briefing & Guide's Divesite Experience, you learn to anticipate an approaching downcurrent before ever getting caught in it; when you see your Dive Guide gesturing early to ascend up and away from the wall, do so without delay and stay together with the Guide.

Especially drift dives along a wall, learn the current direction and reef topography to identify traps where a downcurrent can pull you into deep water. Here is a great and famous example, the south point plateau at the Peleliu Express divesite on an outgoing tide: the dive starts along the wall in 21m/70' flowing right to left towards the southwest. Near the end of the dive the wall subtly changes into a sloping plateau going down to 36m/120' -and this is where many novice divers low on gas get in trouble. They just keep referencing the wall until until they realize the increasing depth too late, and then they get caught in a downcurrent going past the plateau step into the blue water abyss.

Last time there, even I got caught in one coming from the Peleliu Cut: an early AM special advanced dive charter to see the Black Snapper schooling/spawning during a full moon (i.e. very strong currents); was drifting backwards looking up at the fish, carelessly not paying attention, and got swept over the south point plateau in a 3 knot current. Decided to ride it out as it it pulled me down to 36 meters --on Eanx32-- and hence the worst case Nitrox Diver's Dilemma & Nightmare: You just inflate your BCD/Wing and do the best you can to slow or maintain depth and find the downcurrent's boundary; try not at all to physically over exert yourself which induces Hypercapnia which increases the chances of Oxygen Toxicity; hope the downcurrent slacks off in time to ascend back above MOD; and after you escape, deploy your SMB from depth quickly so the boat crew sees you early for eventual surface pick-up (or else if they miss seeing you, your next "pick-up point" is 1000km to the west in Mindanao Philippines ). . .

Again, there are several dynamic variables at play here which will affect the ad hoc action taken: how much breathing gas left (i.e. Do you have enough to ride out the downdraft at whatever depth it takes you?); your physical exertion & breathing rate (signs/symptoms of Hypercapnia); the strength of the downcurrent; reef topography nearby (can you physically climb a reef wall to escape or are you going down in blue water?); and encroaching on a Nitrox/MOD limit.

 

[Dan]

Best prevention is to be informed through Pre-Dive Briefing & Guide's Divesite Experience, you learn to anticipate an approaching downcurrent before ever getting caught in it; when you see your Dive Guide gesturing early to ascend up and away from the wall, do so without delay and stay together with the Guide.

Especially drift dives along a wall, learn the current direction and reef topography to identify traps where a downcurrent can pull you into deep water. Here is a great and famous example, the south point plateau at the Peleliu Express divesite on an outgoing tide: the dive starts along the wall in 21m/70' flowing right to left towards the southwest. Near the end of the dive the wall subtly changes into a sloping plateau going down to 36m/120' -and this is where many novice divers low on gas get in trouble. They just keep referencing the wall until until they realize the increasing depth too late, and then they get caught in a downcurrent going past the plateau step into the blue water abyss.

Last time there, even I got caught in one coming from the Peleliu Cut: an early AM special advanced dive charter to see the Black Snapper schooling/spawning during a full moon (i.e. very strong currents); was drifting backwards looking up at the fish, carelessly not paying attention, and got swept over the south point plateau in a 3 knot current. Decided to ride it out as it it pulled me down to 36 meters --on Eanx32-- and hence the worst case Nitrox Diver's Dilemma & Nightmare: You just inflate your BCD/Wing and do the best you can to slow or maintain depth and find the downcurrent's boundary; try not at all to physically over exert yourself which induces Hypercapnia which increases the chances of Oxygen Toxicity; hope the downcurrent slacks off in time to ascend back above MOD; and after you escape, deploy your SMB from depth quickly so the boat crew sees you early for eventual surface pick-up (or else if they miss seeing you, your next "pick-up point" is 1000km to the west in Mindanao Philippines ). . .

Again, there are several dynamic variables at play here which will affect the ad hoc action taken: how much breathing gas left (i.e. Do you have enough to ride out the downdraft at whatever depth it takes you?); your physical exertion & breathing rate (signs/symptoms of Hypercapnia); the strength of the downcurrent; reef topography nearby (can you physically climb a reef wall to escape or are you going down in blue water?); and encroaching on a Nitrox/MOD limit.

Thanks for sharing your Peleliu Express diving experience. I'm planning to go to Palau with Palau Aggressor II this December. This dive site certainly I don't want to miss it. From what I read, you definitely want to use reef hook on this dive.

This thread Lessons to be learned-Death in Palau seems to have some pretty good tips on how to prepare for the fast current dive.

 

[Dan]

...Decided to ride it out as it it pulled me down to 36 meters --on Eanx32-- and hence the worst case Nitrox Diver's Dilemma & Nightmare: You just inflate your BCD/Wing and do the best you can to slow or maintain depth and find the downcurrent's boundary; try not at all to physically over exert yourself which inducesHypercapnia which increases the chances of Oxygen Toxicity; hope the downcurrent slacks off in time to ascend back above MOD;...

I went to ppO2 =1.47 (44m with EAN27) in Crystal Bay, Nusa Penida, Bali, Indonesia, where is known also for down current, briefly, long enough to take a picture of Mola Mola being cleaned by Emperor angelfish (see my Avatar) without negative consequences. Had a DM watching me closely from the MOD position, hanging on a rock. That's the deepest dive I have ever taken. I don't like deep diving as it is dark, cold, required a lot of gas to breathe on & nothing much to see, but seeing the Mola Mola up close was very tempting at the time.

 

[Kevrumbo]

Thanks for sharing your Peleliu Express diving experience. I'm planning to go to Palau with Palau Aggressor II this December. This dive site certainly I don't want to miss it. From what I read, you definitely want to use reef hook on this dive.

This thread Lessons to be learned-Death in Palau seems to have some pretty good tips on how to prepare for the fast current dive.

Bring a 100' minimum spool line length to launch your SMB earlier in current at depth ranges from 70 to 20fsw if you get seperated from your group and dive guide -doing this gives the dive skiff crew a good & long time chance to spot & track your SMB on the surface as you drift off to the southwest (last landmass is Angaur "Ngeaur" Island; after that is Mindanao Philippines 1000km away).

Don't forget your PLB, especially on this Palau Trip!
●The less info SAR units have about your location, the larger the Search Area.
●The larger the Search Area, the longer the search until you are located.
-->The more accurately you communicate position information, and if your 406 MHz PLB registration information is complete and up-to-date (and especially preparing your designated emergency contact person with having at least phone contact info on the dive operation/liveaboard you're diving with), the better your chances for a speedy recovery.

And also consider:
For Sale - Halcyon Life Raft - As New if you can find one with storage pouch on eBay (see also Klymit Pack Raft). Again the life raft is a good survival tool to ward off immersion hypothermia and get you out of the water; invaluable for remote tropical dive sites with strong currents and the potential hazard of drifting away unseen on the surface from the diveboat. . .

Prepare smartly for a lost at sea scenario, and give yourself every objective foreseeable chance of survival and being found.

-----
(Nice shot of the Mola-Mola avatar too!)

 

[Dan]

Bring a 100' minimum spool line length to launch your SMB earlier in current at depth ranges from 70 to 20fsw if you get seperated from your group and dive guide -doing this gives the dive skiff crew a good & long time chance to spot & track your SMB on the surface as you drift off to the southwest (last landmass is Angaur "Ngeaur" Island; after that is Mindanao Philippines 1000km away).

Don't forget your PLB, especially on this Palau Trip!
●The less info SAR units have about your location, the larger the Search Area.
●The larger the Search Area, the longer the search until you are located.
-->The more accurately you communicate position information, and if your 406 MHz PLB registration information is complete and up-to-date (and especially preparing your designated emergency contact person with having at least phone contact info on the dive operation/liveaboard you're diving with), the better your chances for a speedy recovery.

And also consider:
For Sale - Halcyon Life Raft - As New if you can find one with storage pouch on eBay (see also Klymit Pack Raft). Again the life raft is a good survival tool to ward off immersion hypothermia and get you out of the water; invaluable for remote tropical dive sites with strong currents and the potential hazard of drifting away unseen on the surface from the diveboat. . .

Prepare smartly for a lost at sea scenario, and give yourself every objective foreseeable chance of survival and being found.

-----
(Nice shot of the Mola-Mola avatar too!)

Thanks for the tips. I put as much info in NOAA registration form as possible for my PLB1. My dive buddy will carry his old Nautilus Lifeline.

I'm still contemplating about bringing 100' spool for my DSMB. Currently I only have 20' strings attached to my DSMB in a pouch.

Palau - Sorong (Raja Ampat) is pretty much the same distance (1000km) as Palau - Mindanao. Sorong is straight south from Palau. Either way, that is way off & in the middle of no where.