On 29 Aug 2005 at 0:50, HapSailor1_at_aol.com wrote: > I never heard about this "low-head dam" situation, and I thought that > may be other paddlers should know about it. A low-head dam is a special case of a general situation where water pours over an obstacle and forms a recirculating flow downstream of the object. Any of these recirculating flows can trap you. However, what makes a low-head dam special is that the dam is usually fairly symmetric about the point where a paddler gets trapped. In that situation, there is nothing to push the paddler out and he stays there for a long time. With a smaller or unsymmetric object, the asymmetric flow will tend to cause the paddler to move one way or another away from the trap and allow him to escape. The danger for a rescuer is considerable, since if he gets into the same hole, he is potentially trapped too. One way out of this situation is to swim _down_. You try to get below the recirculating water and hope you are flushed out. If you're really getting maytagged, finding "down" can be tricky. Sometimes, grabbing your ankles and holding yourself in a tight fetal position can cause you to be flushed out of the hole, since the water has less friction on your body. If the momentum of your body swirling in a circle exceeds the forces of the water, you can break free. Not something I've ever had the pleasure of testing. Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sun Aug 28 2005 - 23:36:27 PDT
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