diving in current

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Mateo1147
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Re: diving in current

Postby Mateo1147 » Mon Oct 08, 2018 2:03 pm

Check out this web page with animated tides and currents on NOAA charts. Once you learn to work with it and any offsets needed for your specific dive site you will be amazed how easy diving around the sound can be. I use it religiously for boating and diving.
Remember, they are tide and current predictions, not the last word on what will actually be going on! Even moderate wind can create localized surface currents at some sites. Dives will sometimes need to be scrubbed if conditions don't feel safe for those entering the water.
Happy diving!
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Gdog
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Re: diving in current

Postby Gdog » Tue Sep 25, 2018 9:43 pm

Current is just like the wind when you hold your hand out the car window flat while driving. Use the current to push you down against the bottom by how you position your body, head down, feet higher. If you use your fins to anchor, like Lamont said, then you are effectively allowing the current to push you up away from the bottom. Great advice here from all. Also, there is always some current at Three Tree North. Its a good place to learn to deal with current without getting into more serious current. I remember being stressed at TTN years back on my first dive there, in current. Now that same current doesnt bother me at all, mostly because of diving in it and learning how to deal with it. I also think Laura brought up a great point. Dont get too caught up in fighting current and sucking down your air until you are in real trouble. The surface is directly above you, if you cant deal with the current just ascend. Yes you will drift with it. But you will exit the water alive. Believe it or not, people have gone Out Of Air caught up in fighting current, and died, when all they had to do was just go up. And as Laura also talked about, good old benign Redondo can have some spot currents we call the Redondo River. They are short lived, but it is beneficial to understand them, and how to react to them.

SashimiFencer
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Re: diving in current

Postby SashimiFencer » Tue Sep 25, 2018 6:47 pm

Cool video of the Puget Sound model! And thank you all for the excellent advice! I suspect my kit is still not balanced perfectly-I've been doing fine thus far but perhaps a slightly more challenging situation highlighted the imbalance. And I also suspect that my body did become a sail, so I'll try to tuck down my head and body more next time. More importantly, I know it's best to avoid getting into a similar situation by understanding currents and underwater topography better.

Thanks for the reference books (always love to learn more!) and additional tools for diving.

oh, I wasn't panicking because I knew we were close to shore and to the surface. I was just annoyed at how I couldn't get myself out of the situation! I don't want to be like this :breakdance: again!

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lamont
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Re: diving in current

Postby lamont » Tue Sep 25, 2018 4:05 pm

I did hit a case one time where there was bottom current and no surface current which was at Edmonds UW Park. Current swirling off the jetty was getting pushed out and down and we were swimming into it along the bottom to get back to shore and fighting it the whole way, but pop to the surface and it was negligible.

So had that happen once.... once....

And if you're going negative along the bottom, if there's just silt and nothing to grab, just get a little negative and exhale and just set your belly down into the silt and take a breather (any mess you make doing that is going to get flung away by the current). Use your belly and not your fins. If you try to prop your fins against the silt, you'll make a mess and often your body becomes a sail for the current and can start to flip you over. Get your stomach and head down near the silt. Of course you can streamline your gear and orientation in the water, get your fin kicks down (including the flutter), get your cardio fitness into better shape, and then you'll have to do this less, but simply plopping down into the bottom and/or hanging onto things is something useful to have in your toolbox when there is blasting current. Also useful for tying into the line at ginnie when its howling. Beats overbreathing your reg, taking a CO2 hit and having a bad dive. Stop, breathe and relax, then continue.

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ljjames
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Re: diving in current

Postby ljjames » Tue Sep 25, 2018 3:32 pm

You might want to look a little bit more into this ‘tumbling’/destabilization, it might indicate you and your kit are way out of balance. It sounds like your buddy was not getting tumbled so perhaps discuss the experience with him and understand why he is more stable than you underwater. This compounded what was going on with current. Getting your kit sorted will make the unexpected things much easier to deal with.

Beyond that, I’d recommend what others here like GDog have mentioned, getting heavy (dump gas) getting close to the bottom and crabbing across current as opposed to swimming into it, you can learn a technique called pull and glide often used in cave diving but it can be somewhat helpful in these situations. Additionally if you find yourself at a site without structure, looking at the bottom for geoduck holes as a place to get enough leverage to move across current using modified pull and glide technique without having to use a tool can be useful. Of course a trowel as Fritz mentions is a better alternative to a knife in general for this purpose, more leverage and less likely to break/accidentally stab a creature in the sediment, but i tend to not like extra stuff in my hands when dealing with situations that need extra attention to buoyancy and also extra attention to resources like gas - a tank can be hoovered down in a flash when actually working underwater.

Unless you are absolutely getting wholloped in a downwelling and you absolutely can’t make your way across the current flow up the slope and the only option is to bail, I don’t recommend ascending up into the water column unless you can see that it is obviously slower ‘up there’ as the current is most often a bit slower close to the bottom as the friction of the water/sediment slow it down. I have not really found slower water in the water column to be the case here in the northwest unless you are out on some big wrecks where the sills cause some intersting current movement, things like slack on the bottom and rip snorting current on the way down, this changes when you go to different environments such as caves, rivers and big wrecks and things where learning from someone who knows the water movement of a specific dive is key (sometimes the flow is slow on the ceiling, etc.. sometimes you can use the current for transportation on a wreck, hiding in current shadows for swim one direction and then drifting the length of the wreck in the other, wash/rinse/repeat)

And of course as folks have said, learn your sites. There are two sites that i find a bit notorious for these situations (redondo and les Davis) that have some pretty intense river assisted currents at certain tide changes not really covered in NW shore dives etc. The river water is piled up by the incoming tide and then upon reversal, boom, the current gets a river assist and can surprise even the strongest divers. Often finding a way to hunker down and or slowly make your way across these “rivers” works well because it is a transient phenomenon and once the piled up water has unloaded from the river delta things will return to ‘normal’ for the prediction. Basically right out of openwater one, “stop, think, breathe, act”

Other sites have this to a lesser degree if you are interested in the phenomenon, you can periodically see the ulva flowing ‘downhill’ and ‘uphill’ at cove 2, its never overwhelming but for sure different than the normal slow moving to no moving currents in that back eddy.

In addition to the longshore currents that Yelloweye mentions, there are also topographic current nuances... Alki point (the clay walls off the actual point), can have massive down/upwellings, Don armeni boat launch in the turbidity channel/fault line, north of mee-kwa-mooks as well just to name a few. These are influence by the bathymetry/bottom contours and how the currents hit them when coming around points and stuff. All fascinating, and all kind of predictable once you know what to look for. For a primer you can go to the Pacific Science Center and take a looksie at the tidal model which is a scale replica of the basin and you can see the movement clearly with dye injection.

A great primer for all this (albeit a bit dry) can be seen here as well:


Another interesting read/resource is Curtis Ebbesmeyer’s book “Flotsametrics and the Floating World: How One Man’s Obsession With Runaway Sneakers and Rubber Ducks Revolutionized Ocean Science,”. A bunch of it is about big ocean currents but there is a bit about his early career studying the blobs of water that move around Puget Sound and hood canal that are quite interesting.

Final note to echo what Yelloweye mentions about drifting on surface being better than running out of gas on the bottom... You are pretty much in a bathtub. A BIG bathtub but when you surface there will always be land in sight assuming you are diving in the Sound. It may feel scary but you CAN swim to shore from almost any site in south/mid sound, it may take time but you are not in the middle of the ocean. Swim to shore, you may need to hitch a ride back to your car, it may be embarrassing, but its way better than compounding a bit of an adventure into a potentially life threatening out of gas emergency for you and your buddy.

Disclaimer: i have not actually taught a dive class in a decade or so, but have in the past and don’t think this stuff has changed ;)


SashimiFencer wrote:Hello,
I was at Three Tree North yesterday and got caught in highly undesirable current during flood tide. at 60-80ft, the current was minimal but as we ascended to ~30ft, all of a sudden I got caught in current where I ended up getting rolled around. No matter what I did, I couldn't stay prone. I tried drifting with the current (but still got tumbled), tried swimming into the current (couldn't keep that up). my buddy let me latch onto him (but I ended up tumbling him, too) until things settled down. Any advice on what to do the next time?
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fmerkel
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Re: diving in current

Postby fmerkel » Tue Sep 25, 2018 12:39 pm

All great advice so far, except [planyourdive]. That site is (or at least has been) very poor at helping predict areas where current is actually likely to be an issue. TTN 'generally' has low currents.

2 additional points:
1. If you simply let go, ride the current, while you drift you are effectively no longer in current and can get yourself righted again. If you can't do that, you need to work on basic dive skills or your kit's balance. Frankly, unless the current is really nasty it should not tumble you. Blow you around, frustrate you, exhaust you-sure, but not destroy your orientation.
2. Lots of our sites don't have much to grab onto in the case of current, just gravel, sand, and/or mud. I have found regular dive knives to be of minimal use for an anchor in these areas if the current is strong enough to be an issue. What I have found that works well is a simple garden trowel; cheap, light, pocket-able. It digs in and holds in that kind of bottom allowing you to take a break and get organized.
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YellowEye
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Re: diving in current

Postby YellowEye » Mon Sep 24, 2018 8:16 pm

Hi Sashimi Fencer

Sorry you had a rough ride! Couple of things to think about:

Planning
---------
Definitely take some time to learn about currents... learn to read current graphs and about current stations and corrections. Use planyourdive.com, Dakari.org, or similar. As a rule of thumb, days with full moons (like we have now), or new moons tend to be the worst exchanges.

You can use a book like _Northwest Shore Dives_ or a website like emeralddiving.com to get insights to the water behavior at each site

And take a look at three tree on a map and imagine a flooding tide coming into (heading south into) Puget sound... all that incoming water sweeps Three Tree! You can also see that current will collect and amass near the point. So to avoid current, avoid floods and/or head towards the right at that site.

On an ebb, Three Tree North is pretty protected from the sweep. Unless there's a huge exchange -- then you can get a back eddy, also running out towards the point.

Similarly due to the geography, three tree is protected on a south wind (wind coming from the south). Use a site like https://www.atmos.washington.edu/data/m ... eport.html to take a look at wind forecasts.


Dealing with current
------------------------

If current hits, I usually find that diving very close to the bottom gives you some good protection.... You have less drag. But sometimes going up a foot or two can also help. Depending on the dive site, currents can also be very gusty. If it current is bad one minute, it may be better the next. So go slow and hold on! Inch your way, don't fight it. Some people dig their hands into the sand if there's no structure to hold on to.

Get a feel for current. Do some dives at keystone, at a slightly off slack time, where you can dive with the relative safety of rocks to hold on to. You can go out a bit towards the point, feel current of a specific strength, and see how it feels fighting it back. When you're comfortable, go further against it, etc. Over time you get much more comfortable with the feel of it and it'll be less of a stress next time you hit current. Note that if you hear the ferry coming at Keystone, hold on, it really gets the current running.

Learn to hide in the areas of weaker currents, behind boulders etc. It will allow you to enjoy the best part of the dive site (the high current areas) for extended periods.

If you hit a down welling or upwelling, buoyancy may have to be adjusted. Note that up/down wellings are often localized... head 10-20 feet backwards or forwards along the wall and it may subside...

Also realize that it is better to surface/drift than fight for your life against your current and run out of air... :(

Hope it helps!

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Re: diving in current

Postby SashimiFencer » Mon Sep 24, 2018 5:48 pm

thanks, Gdog. I will try to mimic a crab during my ascent next time I'm in strong current. what I couldn't figure out was how to recover myself once I started tumbling around since there was no structure for me to hang onto. I felt like I was doing this!


(I had gone to TTN with a more experienced diver in the past. The advice I got was not to worry about current since it's not a problem at that site. I :eek: )

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Re: diving in current

Postby Gdog » Mon Sep 24, 2018 3:29 pm

Norris has good advice. And of course, so does Mike! Also, when you are in current like there can be at TTN, if you get low and close to the bottom the current won't push you around as much. Then you can just work your way slowly up the slope, in a sidehilling fashion, or at an angle into the current. The best thing you can do is not allow yourself to get stressed, just take your time and work your way up low to the bottom. While you move up, go slow so you don't exhaust yourself kicking, and don't forget to watch the bottom right in front of your face as you will be surprised at the little Critters you may see!

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Norris
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Re: diving in current

Postby Norris » Mon Sep 24, 2018 3:18 pm

Learn to read tide/current tables. If you are not sure, post on here:
hey all I intend to dive xx at xx time. Are there any divers experienced with this site that could give me some insight as to what I can expect?
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mz53480
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Re: diving in current

Postby mz53480 » Mon Sep 24, 2018 3:02 pm

Stay away from boat propellers...
...I like going to the chamber.. They have great food there, and awsome live music "H20doctor"
Check out the VIDEOS!

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diving in current

Postby SashimiFencer » Mon Sep 24, 2018 1:10 pm

Hello,
I was at Three Tree North yesterday and got caught in highly undesirable current during flood tide. at 60-80ft, the current was minimal but as we ascended to ~30ft, all of a sudden I got caught in current where I ended up getting rolled around. No matter what I did, I couldn't stay prone. I tried drifting with the current (but still got tumbled), tried swimming into the current (couldn't keep that up). my buddy let me latch onto him (but I ended up tumbling him, too) until things settled down. Any advice on what to do the next time?


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