> SURVING DOWNCURRENTS> Diving in South Florida taught me these tips to get your A_S
> out of a down current so this is 1st hand advice!!But I did
> submit this to a dive publication :)! GRATIS!! Because I
> believe in diver education!!
> AND ALL YOU GUYS OUT THERE ARE MY FRIENDS!!
>
> What are down currents you ask?:
> Downcurrents are where a running current sweeps over a
> wall,or a river flows in.And yes, there are these phenomina
> out there!!And there are more than one set of conditions
> that cause them!
>
> CONVERGING HORIZONTAL CURRENTS!
> Yes these cause them.Anywhere you have 2 horizontal currents
> that converge you run a VERY GOOD CHANCE of encountering a
> downcurrent.You can't compress water as you know,(you
> can refer to an earlier blog of mine for the physics), so
> the water is forced to go where? DOWNWARD!! This is a very
> common occurence near the coast, where the lay of the land
> (topography) forces tidal flows to converge. (I learned this
> in Hillsbro Inlet, FL). It can also happen at fronts in open
> ocean, you can usually tell by very well defined lines of
> flotsam,(garbage). Apparently according to research I've
> done these currents can be as strong as 0.25 meters a sec.
> (Thank you Wood's Hole Oceanographic when I called for
> info.).
>
> STRONG SURFACE COOLING (CONVECTION)
> Cooled surface water becomes more dense as it cools and
> sinks.This cooler,sinking water has been reported to form
> into "chimney's for lack of a better word. In the
> North Atlantic there is one spot that actually takes water
> from the surface to the bottom at 1500 meters. ( 1 1/4 of a
> mile!) Pretty scary stuff! I pity my friends in
> SCAPA FLOW UK that have encountered this.
>
> INTERNAL WAVES
> This is another kind of an ocean wave that have a verticle
> motion. Interenal wavesare formed because of the varying
> densities of the layers of water from the surface all the
> way to the ocean floor. These are not tsunami's!!
> You can usually spot these guys propagating towards the
> shore from open ocean and they can sometimes be seen as
> slick lines that run parallel to the shore.
>
> The BEST WAY TO SPOT POSSIBLE DOWNCURRENTS
> Look for well defined lines of flotsam,slicks, or
> windrows.The lines usually will mark the convergence of
> currents and therefore a good place where a downcurrent is
> possible.
>
> SAVING YOUR BUTT!!
> If you happen to find yourself and your buddy caught in one
> of these downcurrent situations you will have a better
> chance of swimming horizontally to get out of this current
> than fighting against it. If you're still being pushed
> downward make a CONTROLLED
> EMERGENCY ASCENT by inflating your BCD, ditching your
> weights or both!!
> I may not be here today to bore you with my blogs if it
> hadn't been for a good friend and buddy in Tarpon
> Springs FL, George Diadonidas,(yes, very greek!). I
> encountered this while diving with him in Hillsbro Inlet on
> the OTHER SIDE of FL from where I lived, I just HAD TO dive
> near the Lighthouse!! Hope you've gained a bit of insite
> about this crazy phenom as I decided to include this one
> because I have a lot of good friends in FL and other coastal
> states.
>
> HAPPY DIVING EVERYONE!!
>
> TOM