The currents
@billt4sf is referring too in his OP are the nasty unpredictable ones you get in Indonesia and other such places. With the greatest respect to the other posters
not those strong drift types you experience in FL etc.
We get the washing machine currents here quite a lot and they can be unpredictable to say the least. For the proponents of freedive fins and the like, let me assure you they don't cut it. I've popped up (knowingly) from the lee of a ridge on a scooter (Dive X) at Max speed. Stopped and gone backwards - finning didn't help one bit. I've also had my bubbles stay in front of me, as well as having to use one hand to keep my reg in and mask on while hanging on with the other. I'm happy to give non believers a taste of these currents.
For my up coming trip to Misool one of the pre dive questionnaire is "do you have experience in currents of 2 knots and above. So you know its going to be a blast
So my tips (hard learned) some of which are a repeat of others here.
Listen to the dive plan. find out what the contingencies are. If it isn't mentioned then ask.
Gas contents. It's especially important to keep an eye. You may realise your breathing is going up but not by how much. My usual is consumption rate is14-16l/min. In a washing machine I've seen my computer register 28l/min so doubling it, and I'm used to them.
Adrenalin kicks in as does your bodies fight or flight reactions which elevate your heart rate so all you can do is try to minimise your consumption increase by trying to stay clam and dealing with it. Being able to de -tune your reg to calm your breathing is also a bonus.
We all normally end normal dives with 100bar in our tanks. In one of these situations, hitting the surface with 30bar or less is common.
I'm a firm believer in AI having all the info on your wrist is where it needs to be. Your spare hand may be used for hanging on not going for your spg.
You need to focus. Terrain, Buddy, Computer. Ignore you're going fast keep an eye on your depth as all your normal senses will be overwhelmed
If you're near the bottom - head for it. If you can find geography to shelter behind then do so even for a moment to get yourself under control.
Unfortunately normally this stuff happens on walls where the sand is too far below to help.
Reef hook. Always carry one. Mine is always stowed in a pocket on my waist belt. My pockets are kept from sliding around by D rings so the cord is always clipped off to one.
If the current picks up I'll move the clip to the ring on my crotch strap. The hook itself has a long shank with a big eye that I can grip without it pulling through my hand to use as a grapple or brake. I also keep a double ender on the eye so I can clip it off after use (pack it away on deck)
The rope of most Reef hooks is too long for high currents. I have a loop half way along mine so I can clip it back to shorten the cord. Also when you're hooked on make yourself slightly negative. so the cord is at a shallow angle and you are near to the ledge etc. If you're too buoyant you'll be pulled upwards with the cord near vertical and you'll just get buffeted by the current.
If you can hook on with the current raging then do so if just to collect your thoughts. Stay close to the wall and use it as a brake or to pull yourself along (these currents can swirl)
Gloves. I know some areas say you can't wear them. Mine go in my pocket anyway. If it starts picking up on go the gloves. I've seen someone's fingers at the end of a dive who didn't wear gloves, not pretty!
Be aware of your surroundings if the water suddenly goes warm - that's surface water coming down - if it suddenly goes cold, then deep water going up. This can be an indicator of trouble ahead. however if you are in a nice slow drift, then its unlikely that these changes will be strong currents.
Down currents are normally recognised by your ears hurting as you get pushed down fast. Yes you are supposed to swim away from the wall out of them. Hard to do as your mind doesn't always work that fast. Get you equalisation sorted and add air to your BCD but be ready to dump and keep an eye on your depth gauge so you know which way you're going. The last one I encountered 2 weeks ago slammed me and my buddy down 22m before we got out.
The trick isn't to make yourself buoyant, you just need to minimise the ride down. You don't want to be filling your BCD to its max capacity
Up currents are easier to spot. Normally caused by geography. If you are being hurled towards a large rock steer yourself around it rather than think you can grab on. I made this mistake once. My Dive comp stopped at 20m as I was blown straight to the surface. (I went back down and sat at 5m for 5 mins but I'd only been in the water for 15mins)
Having your alerts on your PDC set to on works. Often the first indicator of suddenly going up is your computer giving you an ascent alarm
Often the hardest bit is to know if you're going up - you are so disorientated and lose your visual clues. It can happen fast.
You can forget about normal buddy separation. If you are close you're going to hit each other so give yourself some room. Also you will both present different shapes to current so will drift at different speeds. The person in front needs to keep stopping letting the other catch up. Drift stop rest, Drift stop rest is the best way to deal with it.
Because of this we always carry a side slung of Air I use a 40cf, my wife a 30cf - these are both popular sizes here at least
1. You can guarantee you getting to your buddy if you have an issue.
2 If you get pushed down below your MoD you can switch.
3 Gives you extra gas for working things through. Once we got hurled to 50m as the current changed. We were on a pinnicle and had to climb up and around 30m- letting go and swimming out wasn't an option as we'd have been pushed down past 100m. I was happy for my 40cf side sling that day!
Keep you buddy in sight and the others in the group if possible. Apart from the usual reasons it provides you with the comfort that you're not alone. You have enough to worry about without worry about where the others are as do they.
DSMB - Carry one!! It's not always possible to just launch your DSMB you need to get to somewhere with a bit of shelter.
Make sure your buddy is close - One launches the DSMB and the other hangs on (and helps. If the current catches your DSMB you can be like Mary Poppins. I have a rope handle on my reel for my buddy to hold onto in such conditions. I have 50m of line on my reel. I can launch from depth and have no worry about the DSMB running away and me running out of line. Having 10m of line or less is pointless in these currents.
Often the current will ease if you change depth by 10m. We often go down deeper at first to try to get out of it or minimise it (generally the sand is at 100 - 150m so that's not an option) I've found that 15-20m is a good depth as a minimum to stay at as you get some maneuvering room without breaching
If you're not comfortable then get somewhere safe and thumb the dive, otherwise keep going. The only way to get used to these is to encounter them. Your heart beat will race and you will feel out of control and not like it (at first) you need to get somewhere to hang on and get control of yourself. You can then go with the flow, or get to a safe place and get out.
Remember surface currents can be fast too so you want to make sure the boat can see you (big DSMB) and hear you (Airhorn on your LP inflator)
If you must swim towards shelter put your arms out in front superman style, head down and go for it. Remember you won't get that far before you tire. Pick your moment carefully.
If you have a nasty experience best get back in the water asap afterwards and face it again having thought it over. It gets easier each time. If it really scares the cr@p out of you then avoid places with them at all costs.
