Join Date: Apr 2006
Thanked 170 Times in 167 Posts
Rep Power: 12
Re: Boy killed by lightning in our anchorage, what would you do?
sallard, overall I agree with you but note that you don't need a theoretically perfect faraday cage in order to have an effective one. Aircraft windows are about the same size as boat hatches, yet avionics pros will tell you that the aircraft basically IS a very effective faraday cage and they rarely take damage even when struck by lightning. The skin still conducts most of the charge on the OUTSIDE of the aircraft, the same way that AC power is largely conducted on the outside skin of a wire. I don't know the physics, I just have the Cliff notes.
Similarly, if your electronics were "protected" only by having the brealers thrown, that's no protection. The air gap in a breaker flashes over and fails at around 3000 amps discharge. The lighning is pushing way more current and voltage than a breaker is designed to protect against, you might as well say that a spark plug's air gap can "protect" against an ignition system's coil power. Of course, it doesn't.
While professional broadcasters DO use more effective lightning protecction devices (like PolyPhaser) and those devices work very effectively to protect towers and transmitters that never are unplugged, those folks also do go off the air due to lightning damage at times. Despite the best of protection and expert installation.
Bottom line, to protect electronics you do what radio operators have done for a very long time: You ground the antenna cable, outside of the radio room (i.e. above deck or at the mast) and the antenna and cable iteself are sacrificial items. Once the electronics are really isolated, they are safer. But that means unplugging everything every time you step off the boat, and then the connectors fail, or the job becomes a nuisance that just won't get done.
Lightning: God's way of playing golf. Always hitting par, often scoring hole in one.