T&T: lightning protection

[Larry N. Brown]

It's my distinct pleasure to inform the list that MV Cigano had the first
operational test of the ship's lightning protection system about an hour ago.
Ship and crew made it through with flying colors. The Admiral and I were
taking a siesta in the master stateroom aft, lured off into dreamland with the
distant sounds of thunder and falling rain. Thunder got a little louder but we
slumbered on. Then, crack. A VERY loud clap of thunder and the room turned
pink through my eyelids. I woke up fast.

Lower radar was out. Got on the internet and checked. Sure enough, a weak
squall line was passing through and that produced the storm that hit us. After
waiting a prudent time for the action to move out, I went topside to check the
damage. FB radar showed the cells moving NE-ward. Looked to our "bottle-brush"
and realized that we'd been hit. Many of the little "porcupine quills" were
missing, several had globules of steel on half-length pieces and the whole
thing was inclined over about 50d at the base. Heat must have weakened it and
gravity took over. Whew.

That said, let me tell you what our system is. The highest point on the boat
is actually the radar mast, but the dink hoist is a close second. We installed
an 18" bottle brush diffuser/attracter which then becomes highest point. The
dink hoist passes through the hardtop and is flanged to the hardtop. It's tied
into the stanchions on the sundeck with 0000 battery cable, crimped and
soldered and very gently curved. Then the battery cable goes straight into the
lazarette and through the hull to a piece of s. bronze 4" wide by 4' long,
spaced 1/4" off the hull. and faired in at the tips so as not to catch crab
lines.

It's not tied into DC ground or AC ground or bonding ground. It stands alone
per Nigel Calder.

No hole in the hull, turned off both radars and reset them and they're fine,
no loss of AC or DC systems. Scared the living bejesus out of me, the Admiral
and the dog but by martini hour this afternoon, it will be just another
seafaring story to tell.

We've had the discussion endlessly here on lightning protection. Do you try to
diffuse the downward bolt or attract it to ground? I don't know but I do know
that our system effectively contained the charge this time round.

BTW, we're leaving next week for a series of mini shakedown cruises prior to
launching out on the big one. Feel a burning desire to catch fish.

Regards,

Larry and Teri
M/V Cigano, 47' Prairie Sundeck
Lying:   Covington, LA but not for long