To further stir the pot on the subject of lightning: Lightning can stroke from the GROUND to the SKY. So a stroke starting under your butt in a boat can follow a very different path as it seeks the cloud, compared to one coming the other way. Others have advised checking the weather, hiding appropriately (if on land), scrunching down in the yak etc. To this I would add: If inside a building, stay away from AC power boxes, metal ductwork etc. since ground-to-cloud strikes often originate at these points. The best solution of all is to not be where the lightning is! AN ARRESTOR SYSTEM There is enough energy in one lightning bolt to lift a 40,000-ton ocean liner four feet into the air! Somehow we need to divert all of that energy safely away in a few hundredths of a second. Short of building a completely enclosed Faraday-shielded cockpit, the following must be taken into account: 1) A lightning rod provides a "cone of protection" (45 degree angle). A sixteen-foot boat would therefore be protected by a rod 8 feet high if it were located at the midpoint of the boat. 2) The lightning rod is only half the solution. Once grabbed out of the sky, the stroke has to be guided safely to GROUND! Without a low-resistance path all the way to the ground, your flesh becomes an inviting path. Extending the bottom of the metal "sky rod" several more feet down into the water (where it becomes a "ground rod") is a good theoretical solution. A single STRAIGHT pipe would be a good way to do this because lightning sees kinks as HIGH RESISTANCE and it will jump off the arrestor system where there are kinks. A straight pipe has no kinks. In a metal frame kayak, I believe such an arrestor system should be insulated from the frame, to minimize the likelihood of flashover to you or of inductive coupling. I would suggest sitting a foot or two away from (and ahead of) the rod (since your feet are sticking out in front of you). 3) Instead of a continuous pipe, a more practical ground system might be built by dropping a heavy ground wire into the water and letting it sink. (The idea of a TRAILING ground wire that some have suggested, means you are still paddling, which I think is dangerous. And note that if you paddle, you will probably create a deadly kink in that ground wire where it separates from the vertical arrestor pipe as it trails behind you!) If caught in a storm, it seems to me you should stow the paddle, deploy the lightning arrestor system (ground wire first) and then scrunch down into the cockpit. Oh yeah - and plug your ears. I leave it to others to arrive at a design that takes into consideration mounting, corrosion, and the right materials. (For example, welding the wire to the mast is better than bolting.) A metal-frame yak should have all members electrically bonded to the arrestor system at one point, but I don't see how this is feasible. 4) If you insist on paddling with it all deployed, use an arrangement that ensures there is a SMOOTH bend (radius: one foot) in the ground wire where it comes away from the mast (above the water line). A PVC tube to route the wire aft is possible. The alternative is to use the continuous mast arrangement that extends down into the water, as mentioned in #2 above, though the drag would be large. 5) A possible alternative system is to use a small lightning rod atop an INSULATED 8-foot mast. Attach the heavy ground wire (weighted at the free end so it stays submerged) to the lightning rod up there at the TOP of the mast. It would trail away from the top of the mast at a gentle slope thereby avoiding the kinking problem - both while you are sitting still (in which case the wire will sink and become vertical) and while paddling (if you are foolish enough to want to). But if it gets windy enough to blow that ground wire across the deck (or you), things could get ugly. Knowing exactly WHEN to set up any such contraption could be a challenge: If you wait until the storm is upon you before setting it all up, you could get nailed while you're setting it up. On the other hand, setting it up too soon and then just waiting there watching your life pass before your eyes, could waste precious time that might have gotten you to shore. These ideas are theory only. Use them at your own risk! If you get killed, don't come running to me... And finally, I am wondering whether setting up such a system would end up attract that lightning bolt that would have otherwise landed elsewhere if there were no protection system at all. See http://www.boatsafe.com/nauticalknowhow/lightning.htm or http://lightningsafety.com +++++++++ Ken Lalonde, Kayaking Wannabe Edmonton, Alberta, Canada *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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