lightning protection

[Bobg]

Just got back from ASA sailing school, old salt instructor said our exposed keel bolts in the bilge is a perfect place to install a strap, (battery cable) or such, he said to bolt it to the mast and to one of the keel bolts. Any Ideas in this one?  thanks  Bob    34 1988 model

[Jon Schneider]

That's how mine came; thought it was factory standard (1990 year).

[karista]

That is exactly how my boat is wired for lightning protection, but in addition to running a 2 gauge wire from the mast, I also connected 2 cables (2 gauge) from each upper chain plate to the keel bolts. This was recommended by a experienced surveyor who inspected a boat severly damaged by lightning.

[Bobg]

Thanks, I feel a lot better now and will do it.  How did you route the #2 cable from the upper chain plates to the bilge?  Thank you all.  Bob on "Ghostrider"

[BillG]

When you talk about bolting a cable to the mast, where exactly is it bolted on the mast?  Would connecting  a cable to the chainplates serve the same purpose?

[karista]

I made up 2 cables  (2 gauge thinned wire), measured the length from the upper chainplate rods to the nearest keel bolt. Crimped on  battery cable lug connectors on each end (which fit over the chain plate rod threads and keel bolt thread) and then just fasten the lug
connectors.
The wire on the mast was installed at the mast step (keel mounted mast), tapped for 5/16 or 3/8 thread (don't remember exact thread size)
Bought a very short 2 gauge battery wire, complete with lugs, that fit the keel bolt as well as the mast thread.

[waterdog]

In my life off the boat, I work in a company that makes bits that attach to the electrical grid.   Every week we have something in the high voltage lab where we test with impulses around 1,000,000 Volts.  It is very interesting stuff and the  and when failure occurs the electrical arc is not always established exactly where we think it will.   Every now and then we do destructive testing in the high power lab.   This is voltage with the current to back it up.   If you are not prepared for it, you may need to change your underwear after witnessing one of these tests.   Here we use fuse wires to establish electrical arcs.   The wires burn up but the arc persists. 

I'm not a technical expert by any means, but I will say, try to think like an electron.  Your mission is to go to "ground", in this case the ocean, by easiest path - usually the most direct path.   Once you get together with a lot of your buddies nothing will stop you.  If somebody tries to make you turn a sharp corner it might be easier just to blow your way through the hull.   

So wiring for lightning bonding is nothing like hooking up the new windlass.   The current will exceed the rating of any wire, fuse or circuit breaker on your boat.   If your connect chain plates to keels, keep the path as direct as possible.   If you decide to route around the holding tank and work your way back through a convenient conduit, the lightning bolt might decide that the path through your macerator pump and out the through hull is the preferred route.  Insulation on the wire means absolutely nothing.  It's only corrosion protection.   Think of your bonding wires as these little paths that will suggest to a bolt of energy where it might like to go and then imagine that the wire burns up but the arc is still there and free to roam.     

Remember to have a conical plug tied up next to every through hull - it is at least as important as any bonding wire...

[Kyle Ewing]

The owners manuals on this board (page 57 in MK I and 65 in MK II) contain extensive information on lightning protection including ABYC guidelines.  Lightning protection was not standard on Catalina 34s.

I've read that bettery jump start cables clamped to the shrouds when a storm approaches is more effective than internal cabling because it offers a straighter path from the shrouds to the water.  Is anyone concerned that by fully grounding your mast you increase the chance that it will be hit by lightning?