Surface Current Question

[Kineese]

Question about managing surface current!

Was shore diving with my buddy recently and the initial plan was to surface swim out, descend down a buoy, putz around there, then at half tank turn and follow the slope back to shore. My buddy and I are fairly new so his air consumption was a bit higher than we anticipated so we ended up ascending sooner. No big problem, just surface swim back! However, in the time we were under a bit of a tidal current picked up. It was fairly mild and I could swim against/perpendicular to it okay (Directly against it was back to our entry point so we decided to swim perpendicular to shallower water then walk from there), my buddy on the other hand had a fairly inefficient kick (lots of bendy knees, not much propulsion) and I ended up towing him a bit so that we didn't get pushed to far away from the entry point as we were making our way shallower.

I had 1200psi left and probably could have descended and made it back but he had 600psi so we felt like that wasn't an option. We got out just fine. No panicking, just tired and a longer walk in gear (no more than 200m from out entry point, but my spatial perception is awful so +/- 500m). The current was not super strong but it got me wondering what would have happened if it was stronger cause my buddy definitely wasn't the strongest kicker and my legs were not fantastic enough to carry both of us against the current.

Any advice or things you would have done differently?

 

[CuzzA]

What was the depth coming in?

 

[Diver0001]

First, just to make sure I understand you correctly, perpendicular is not into the current. When you are swimming perpendicular to the current then the current will be hitting your body from either the left or the right, not from the front.

What you should have done, and what it looks like you did in this situation was to swim perpendicular the the current and let it carry your downstream from the exit as you made your way to shore. Even with an inefficient kick your buddy should have been able to swim perpendicular to the current and eventually get to shore. Naturally, with an inefficient kick this will take more time and will put you on shore further from the exit.

At the moment you made the decision to swim to shore like this then you need to put it out of your head how far you will end up from where you wanted to be. Barring any provocative situations like an impending water fall or getting swept into a shipping lane, you should just keep working at it at a tempo that you can maintain and you will get to shore where you get to shore.

My guess is that you were slightly into the current and therefore having trouble with the swimming. If this happens again then try to make sure the current is coming more from the left or the right (whatever is relevant) and you shouldn't feel the current much at all while swimming forward.

 

[Kineese]

What was the depth coming in?

We ascended up a line with about 10m of water below us (safety stop, slow ascent, all that jazz)

At the moment you made the decision to swim to shore like this then you need to put it out of your head how far you will end up from where you wanted to be. Barring any provocative situations like an impending water fall or getting swept into a shipping lane, you should just keep working at it at a tempo that you can maintain and you will get to shore where you get to shore.

My guess is that you were slightly into the current and therefore having trouble with the swimming. If this happens again then try to make sure the current is coming more from the left or the right (whatever is relevant) and you shouldn't feel the current much at all while swimming forward.

We were probably swimming about 45-60 degrees thinking back because it was still a bit difficult but we made good distance towards a certain part of the shore. I'm glad we didn't have to deal with any impending doom situations but I think we were annoyed that we would have to walk but I like your suggestion of just putting out of your head about were you want to be.

Thanks for the replies!

 

[dumpsterDiver]

If it was shallow (like 10 meters), I would have descended to the bottom and done more of the swim on the bottom. You can move much, much more efficiently on the bottom by pulling yourself along and generally the current is less there.

Putting yourselves in a situation where you have to tow a diver on the surface is not something I want to do for any length of time or distance if I can avoid it. Unless you are a very, very strong swimmer, pulling a tired diver on the surface while wearing scuba gear is very slow and tiring. I have never had to do it - except for short little tired swimmer/diver rescues.

I might have considered the following:

• Take a compass heading to shore from the surface.
• Estimate distance and probable time to swim in on the bottom.
• Take stock of your air supplies, agree on a minimum ascent pressure and suggest that the two of you share your air supply (via an octopus) once you reach the bottom.
• Swim, and pull and follow the compass on the bottom until you get to 4-500 psi and then tell the buddy to switch to his own air supply and then both ascend. Then swim on the surface.

Saving a bunch of air in your tanks and then getting yourselves into a tired diver/towing situation when the water is shallow and you still have a good bit of air is not the choice I would make.

You are comfortable swimming and sharing air underwater, right?

 

[jseyfert3]

Was shore diving with my buddy recently and the initial plan was to surface swim out, descend down a buoy, putz around there, then at half tank turn and follow the slope back to shore.

Just to clarify, was that turn at half a tank being half of your starting pressure, or half of what remains after you take 500 for reserve and whatever you need for asending/safety stop?

If you say 500 for reserve and 200 for ascent/safety (I'm not sure if you need to add this if you follow the shore all the way up), that's 700 PSI. If you start at 3000, you have: 3000 - 700 = 2300 PSI of usable air for going out and back. 2300/2 = 1150, which is the max air you can use going out. Now take the starting pressure and subtract the air you can use going out: 3000 - 1150 = 1850 PSI, which is your turn pressure. Not leaving a reserve or ascent pressure and saying half a tank turn means you turn at 1500. It may not seem like a lot of difference, but means if nothing goes wrong you will have 700 PSI when you return to your start point for the 200 PSI ascent/safety and you surface with 500 PSI left. If something goes wrong, then that 500 PSI is your safety net. If you want an extra safety factor, for unexpected currents, perhaps, you could take 2300 and divide by 3 instead of 2, which leaves twice as much air (in addition to your ascent and reserve) coming in as you use going out.

Ignore if you did this and didn't mention it because it was obvious. I'm a noob who hasn't even gone on my first dive past OW certification (going on a quarry trip the 15th), it just caught my eye when you said turn at half a tank and I wanted to be sure.

 

[TMHeimer]

Each "current" situation is different. Given a choice, I'd prefer to shore dive with an incoming tide. If the tide is ebbing, you are getting a tiny push going out that is unnoticable, but going into it back to shore can be. Dumpster Diver has a good list. Sometimes I have turned on the jets and surface swam back in to a shallower area, then descended to get to shore--pulling myself along the bottom--rocks if possible. Unless you know the site very well, best to take a compass reading if you are to descend to the bottom and swim there to return to shore. Of course, maintain orientation facing the shore while you descend. How much air you have left is of course a factor. Then there is taking into account a buddy's situation, if you have one. Agree also of course about getting to shore anywhere, rather than worrying about your planned exit spot.

 

[CuzzA]

@dumpsterDiver's reply was where I was going with my depth question. Even though your buddy is an air hog, the both of you had a combined 1800 pounds of gas in skinny water. Do what DD said, drop down to ~20 feet and head to shore.

 

[Bob DBF]

DD had the best solution.

This is one of the reasons I have more interest in the return from the dive than in the entrance and the dive itself. Up here on the NorCal coast, if you miss your exit, it can be hundreds of yards, if not a mile or more, before you can find a viable exit. A couple of years back a diver died from a fall when climbing a cliff after being swept down the coast and trying an unknown exit.

Congratulations, you got a cheap lesson, I always hope for those but they are few and far between for me.


Bob

 

[nolatom]

You didn't get anxious or panicked, you "worked the problem", and adjusted your course so you could make progress notwithstanding the surface current.

While i agree with the good advice about (ideally) making more of your approach near the bottom, your plan may have been less stressful for your air-huffing, weak-finning buddy. On the surface you had more work to do, but maybe less chance of him getting too anxious, which who knows, might have led to more serious problems.

Your plan worked, and you "worked a plan", instead of wearing out both of you bucking the current to get "home" rather than "close enough to home".

For someone new enough to be posting in New Diver Forum, I think you done pretty good...