Tips for dealing with surge?

[naick]

Arround here I mostly do shore dives in a place where the tides can be very strong sometimes and the viz ranges from 0,5 to 3m usually. I'm pretty good at underwater navigation, but with bad conditions, strong currents and bad viz I've surfaced 100 feet and on some rare occasions even 200-300 feet from the entry point. It's not that big of a deal, just walk/swim to where you need to be. Next time it'll be better. There are no medals for surfacing within 10 feet of your entry point, just enjoy your diving and look at the fishies

 

[MXGratefulDiver]

Hey Karen ... I bet you did way better than these folks ... and they ended up in Dive Training Magazine ...

Seriously ... navigation by counting kick cycles is not very useful except as a class exercise. First off, it takes way more mental bandwidth than just looking around at objects you will want to notice on the way back, paying attention to your depth and direction, and looking at visual clues like the direction of current or ripple marks in the bottom.

But it does provide a useful way for you to see the significance of things like current and surge over short distances ... which is why they use it.

It sounds to me like you did OK under less than ideal conditions ... and what you learned went well beyond simply learning how to follow a compass heading. Dealing with surge takes some practice. I'd second Walter's recommendations above.

... Bob (Grateful Diver)

 

[Scott L]

Seriously ... navigation by counting kick cycles is not very useful except as a class exercise. First off, it takes way more mental bandwidth than just looking around at objects you will want to notice on the way back, paying attention to your depth and direction, and looking at visual clues like the direction of current or ripple marks in the bottom.

But it does provide a useful way for you to see the significance of things like current and surge over short distances ... which is why they use it.

Who could keep count with split fin usage?

 

[Quero]

Who could keep count with split fin usage?

Oh, that's simple. Just use a little arithmetic: you multiply by two because each fin has two parts, and then you halve the resulting total, because the fins are split in half.

 

[Charlie99]

Seriously ... navigation by counting kick cycles is not very useful except as a class exercise. First off, it takes way more mental bandwidth than just looking around at objects you will want to notice on the way back, paying attention to your depth and direction, and looking at visual clues like the direction of current or ripple marks in the bottom.

I also used to think it took too much mental bandwidth, but then I started diving a site where it was useful to take a shortcut over featureless sand. While doing this I routinely kind of counted, paying only half attention to the count while looking for big stuff out and about over the sand.

One day I was swimming merrily along when I said "Whoooooah. I just hit 50, and I should have hit the reef by 40". Sure enough, the swells over the last couple of days had changed the direction of the ripple pattern and by using the same standard angle off of them, I had veered to the left and missed the reef.

It might be because I'm using a frog kick, at a constant once per 3 second rate, but I've gotten so it has because a nearly subconscious thing to count kick cycles when moving off into more or less featureless areas.

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I find kick cycles is good for the shorter distances, while my computer (which only shows full minutes and no seconds) is useful for longer transits, such as the 20 to 22 minute transit it takes me to get out to a wreck near shore in Maui.

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Getting back closer to the thread topic ....... I don't find that surge affects my navigation at all, but current affects it in a way that might seem strange.

If I'm doing a transit with a cross current, I have a tendency to move UPcurrent. It took me a while to discover that what was happening is that I would pick a point on my compass heading and swim towards it. To continue to move directly towards it, I would crab upcurrent a bit .. in other words, I'd point upcurrent slightly to counteract the crosscurrent in order to end up moving directly towards my chosen point.

The problem is when I got lazy and would look directly forward to pick out another point to use as my target. Because I'm pointing upcurrent a bit, my next selection of target point is upcurrent of the desired track. I would check compass for most new targets, but choosing just a few by eye without taking into account my upcurrent angle would result in me being signficantly upcurrent at the end of a 15+ minute transit.

 

[gcbryan]

I'll also point out that surge might mean different things to different people. Or rather surge is stronger in some locations that in others.

Surge is generally felt mainly from the surface to 30 fsw in my experience. However I was once at a place just off the Washington coast (Duncan Rock) and surge was felt (although not particularly meaningful) down at 100 fsw. At 20 fsw it was so bad that we had to go back to 30 fsw to do our safety stop and shoot a bag. By the time we were in the 20 fsw range in addition to going left and right we were also going up and down by 10 feet.

So there is rocking the cradle surge and there is washing machine surge

 

[TSandM]

If I'm doing a transit with a cross current, I have a tendency to move UPcurrent. It took me a while to discover that what was happening is that I would pick a point on my compass heading and swim towards it. To continue to move directly towards it, I would crab upcurrent a bit .. in other words, I'd point upcurrent slightly to counteract the crosscurrent in order to end up moving directly towards my chosen point.

The problem is when I got lazy and would look directly forward to pick out another point to use as my target. Because I'm pointing upcurrent a bit, my next selection of target point is upcurrent of the desired track. I would check compass for most new targets, but choosing just a few by eye without taking into account my upcurrent angle would result in me being signficantly upcurrent at the end of a 15+ minute transit.

Interesting, Charlie. I have also found that my "crabbing" angle will tend to keep increasing until I'm swimming upcurrent. I don't know why, but it seems to happen to the folks I dive with as well.

 

[Charlie99]

It took two swims out to St. Anthony's before I figured out what was going on. It's not fun to swim for 20 minutes and not find a wreck where you expect it. It gave me some motivation to figure it out.

Watch yourself on the next cross current swim and you'll probably find that you are doing the same thing as I was doing .... confusing the direction you are pointing with the desired direction of movement.

And yes, if you don't know you are doing this, with each new target point you head more and more upcurrent.

Once I know what was going on, I became more conscious of the "crab angle" and would pick out a new target spot taking that into account. Problem solved. Of course, the more precise method is to pick out each new target by using a compass, or to use a swimboard/compass held in front of you all the time, but in practice I've found that once I figured out what the problem was, it was trivial to adjust for.

 

[TexasKaren68]

So there is rocking the cradle surge and there is washing machine surge

I was in rocking the cradle surge.

Babies throw up a lot, don't they

 

[gcbryan]

I was in rocking the cradle surge.

Babies throw up a lot, don't they

I started taking Dramamine when going to sites that have constant surge as well! It doesn't bother me immediately but after 30 minutes...Dramamine is welcome...especially if two dives are planned at the same spot.