My 1988 BCC #86 “Patience” was apparently hit by lightning while moored the other day.
The bonding system has to be very good, because there was very little damage. The mast-
mounted metal whip VHF antenna is missing, a charred piece is all I found. Strangely, the
VHF radio still works, as do all the electrical devices, GPS, alternator, except the radar. The
radar, a vintage, beautiful Raytheon RL10 seems to be mortally wounded. It lights up but a
high pitch alarm sounds continously and targets are not detected. I assume the radome
has crossed over to the afterlife.
The other strange side effect is that 2 seacocks are seized. They where old and kinda
drippy already, but they where greased and used to move easily. Now I can’t turn them,
even after loosening the “packing” nuts…I assume they got zapped. They still weep, which
makes me a little nervous. If I can’t figure out how to un-seize them and “pack” them
properly, I am going to have to haul out and replace…lots of $$$$$. I need the boat in
complete seaworthiness condition for an offshore passage to Nova Scotia.
If anyone has experience servicing these bronze seacocks (I forget the brand right now),
let me know. They are all bronze and have 2 nuts that hold the pieces together (2nd one is
just for locking the first one)
Very interesting. Julian, do you have grounding cables/straps from
your mast to the water? I had considered installing this a while
back, but never got to it. Godspeed has been hit by ligthning twice,
but never had damage, so I’ve not been eager to clutter the rigging
with cables hanging down into the water.
It would be interesting to know if others have taken any steps to
protect their vessel from lightning strikes…
My 1988 BCC #86 “Patience” was apparently hit by lightning while
moored the other day.
The bonding system has to be very good, because there was very
little damage. The mast-
mounted metal whip VHF antenna is missing, a charred piece is all
I found. Strangely, the
VHF radio still works, as do all the electrical devices, GPS,
alternator, except the radar. The
radar, a vintage, beautiful Raytheon RL10 seems to be mortally
wounded. It lights up but a
high pitch alarm sounds continously and targets are not detected.
I assume the radome
has crossed over to the afterlife.
The other strange side effect is that 2 seacocks are seized. They
where old and kinda
drippy already, but they where greased and used to move easily.
Now I can’t turn them,
even after loosening the “packing” nuts…I assume they got
zapped. They still weep, which
makes me a little nervous. If I can’t figure out how to un-seize
them and “pack” them
properly, I am going to have to haul out and replace…lots of
$$$$$. I need the boat in
complete seaworthiness condition for an offshore passage to Nova
Scotia.
If anyone has experience servicing these bronze seacocks (I forget
the brand right now),
let me know. They are all bronze and have 2 nuts that hold the
pieces together (2nd one is
just for locking the first one)
The lightning strike went to ground (the water) via your seacocks and through hulls. Probably through your prop shaft too. My strongest hunch is that the lightning strike has welded your sea cocks together. More than that, from what I've seen of lightning struck hardware, it's very possible that the thru-hulls themselves have been damaged. Without a doubt, I wouldn't attempt much without hauling the boat out. At the very least, have those tapered softwood bungs and a mallet handy! Could get quite exciting.
Another casualty is often the compass! How is yours doing?
The best recommendation I've seen on strike protection is a 1 square foot (or larger)metal (silicon bronze) plate well below the waterline. Thru bolt this with S/B bolts around it's perimeter. These bolts should be wired to the mast and at least the cap shrouds with #6 or larger cable. Minimize bends. Go to the trouble to isolate your VHF antenna at the masthead so that this plate isn't connected to DC negative in any way. You may use this plate for your SSB counterpoise provided you isolate it from DC ground with a capacitor. Ideally you would connect ALL of your standing rigging to this, as well as your lifelines, but it isn't going to make an important difference in a 240,000 volt strike.
DO NOT connect your seacocks or other underwater metal objects to this plate. Many risks, not the least of which is electrolysis. I'm not a fan of 'bonding' underwater metal together. I keep all underwater metal the same composition, e.g. bronze prop shaft instead of a stainless shaft with a bronze prop. This keeps galvanic potential to zero volts. Then, isolate your DC (negative) system from the water except at the prop shaft. If you really must have an AC/shore power system aboard, it also must be grounded to the engine and you are begging for trouble in hot marinas.
My 1988 BCC #86 "Patience" was apparently hit by lightning while moored the other day. The bonding system has to be very good, because there was very little damage. The mast- mounted metal whip VHF antenna is missing, a charred piece is all I found. Strangely, the VHF radio still works, as do all the electrical devices, GPS, alternator, except the radar. The radar, a vintage, beautiful Raytheon RL10 seems to be mortally wounded. It lights up but a high pitch alarm sounds continously and targets are not detected. I assume the radome has crossed over to the afterlife.
The other strange side effect is that 2 seacocks are seized. They where old and kinda drippy already, but they where greased and used to move easily. Now I can't turn them, even after loosening the "packing" nuts...I assume they got zapped. They still weep, which makes me a little nervous. If I can't figure out how to un-seize them and "pack" them properly, I am going to have to haul out and replace...lots of $$$$$. I need the boat in complete seaworthiness condition for an offshore passage to Nova Scotia.
If anyone has experience servicing these bronze seacocks (I forget the brand right now), let me know. They are all bronze and have 2 nuts that hold the pieces together (2nd one is just for locking the first one)
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Clearly, what to do about lightning protection has about as many solutions
as the number of people asked. Core problem is, even the meteorologists
will confess that they don’t have a good handle on the dynamics of the beast.
I have a 6 foot copper strip on the outside of my hull. It attaches with
3 studs brazed to the strip and through bolted to the hull. I also bedded
it with 3M 5200. It is machined to create the equivalent of 24 feet of
sharp edge. The theory that made the most sense to me was that the charge
dissipates best from a sharp edge and that lightning is happiest following
a straight line. I have connected the base of the mast to one of the studs
with a #4 cable. There is also a “lightning rod” at the top of my
mast. It is still on my list-to-do to run 6AWG wire from the cap shroud
chain plate bolts to the other two studs coming through the hull.
There is a rumor floating around that the porous plates, used for SSB and
other grounding, tend to boil and/or explode when passing lightning
voltages. Urban legend perhaps but I didn’t want to find out it was true
as I sank slowly into the sunset. Seemed to me that, worst case, my copper
strip would melt but leave a waterproof blob of copper stuck to the hull.
I am taking the Nigel Calder approach of staying unbonded. Though forced
to ground DC and shore power through the prop shaft, all the through hulls
cannot make a circuit as the rubber hoses isolate them. I do have a
galvanic isolator in the AC circuit to prevent someone else from using me
as their ground in the marina.
I purchased the copper strip as a kit. I will dig through my old records
to find the manufacturer if anyone is interested.