technical question

Oct 30, 2019
148
As I understand it, when aluminum is anodized its surface becomes
non-conductive. If this is so, would it mean that an anodized mast
would be less susceptible to lightning strikes than non-adonized?

Victor
 
Oct 2, 2005
86
Hi Victor,

I for one very much doubt that it would make any significant difference, even if true.
Consider for instance that by the time the lightning strikes your mast, looking for the
easiest path to ground, it has already travelled thousands of feet through the air (well, sort
of...) and a few fractions of an inch of non-conductive material covering a very conductive
material (non-anodized aluminum) would not be much of an obstacle. The issue of
grounding or not grounding your boat to protect against lightning is a far more ambigious
issue, however, and could certainly spark some debate.

Hans Ericsson--Whisper
 
Nov 8, 2003
166
Hi Victor,
I have also wondered about the whole lightning / grounding thing.
Truth is, the more articles I read about this subject by supposedly
knowledgable authorities, and the conflicting views presented, the
more confused I got. Let's face it, Lightning will srike TREES.
Trees are made of WOOD, a supposedly non-conductive material. And it
is not always the tallest tree in the strike area. I personaly have
not heard of any sailboat in a marina with hundreds of other
sailboats around beening hit. Surely some are well grounded while
others have nothing in the way of grounding. Even those boats that
are anchored out with all chain should present a certain path to
ground for lightning but somehow escape being hit. I really don't
know the answer but would very much listen to any advise or musings
of anyone who has spent alot of time on the water and their first
hand experiences. So please let us know what you experienced old
salts think.
Thank you in advance.
Robert
 
Nov 8, 2003
166
Colin,
I think you're right. I also worked offshore in the Gulf of Mexico
on oil and gas production platforms for 13 years. Can't say that we
were ever hit. The crew boats that serviced the platforms has never
been struck either that I know of. I agree and don'nt think too much
about it. (Is your vega grounded? Do you have a strap run to a hull
plate?) Well, I guess I think about it a little !!
Robert
 
Nov 8, 2001
1,818
Hi All

Think the answer is if you get hit then put your head between your legs,
whistle dixie and say a prayer....

Friend of mine hit a 440,000 volt line with his mast, standing rigging
vapiourised, instruments blew and the gold chain around his neck
vapourised leaving a scar to this day. He was OK but very shaken. He is
still with us and still sailing. He just delivered a yacht across
tehAtlantic so hasn't stoopped him.

Cheers all

Steve Birch (Technical)
 
Dec 11, 2007
179
- - port st. lucie,fl.
As to boats being hit in marinas, the boat in the slip beside me in
St.Petersberg, had his vhf antenna hit. The antenna exploded,
showering me with bits of circuit board and charred remains. Took
out his electronics. No damage otherwise. Years ago, I saw a small
Morgan sailboat that had been hit. A fireball formed inside the
cabin and exited thru the hull, leaving behind many small charred
holes about 1/4dia in the sides of the hull.The interior cabinetry
was blown apart. Quite a mess, but the boat didn't sink.
Richard Coe V1812
 
Jul 10, 2009
125
No have not taken any grounding precautions for lightning. I have my
engine block and thruhulls connected but that is an effort to create a
ground plane for the HF transceiver. If a storm is near I disconnect the
antennas in a token attempt at saving the radios! Colin...
moondance5003 wrote:
 
Mar 28, 2003
27
My last boat, a Pearson Commander (26'), was hit while on its mooring, 1/2 a
mile downstream from where it had been hit at the previous owners dock. It
did not have lightening protection from the mast, where the boat showed signs
of having been hit.
In both cases, the lightening traveled down the stays to the chain plates,
thru the hull to the water. Every place there was a wave peak along the hull,
there was a pit mark in the gel coat. Near the water line at the chain
plates, the damage was more pronounced - a golf ball size scoop out of the
fibreglass amidships and delamination at the bow that I could stick a car key all
the way along. There was separation laterally from the amidships water intake
thru hulls to the motor mounts. When pulled-out, there was a siperweb of pit
marks every several inches all about the lead keel. There were no
electronics onboard to speak of, although some of the smaller guage wiring in the
cabin melted, leaving scorch marks along the former path of the wire in places.
The engine never started again. I was lucky this "classic plastic" hull was
as sturdy as it was. I easily could have sunk, or the gas engine/tank
exploded. I was glad not to have been onboard at the time.
The first time the boat was hit, the former owner's insurance company redid
the hull and applied extra glass between the motor mounts and thru hull. My
company totaled the boat and I chose to walk away from her in part because I
saw the results of the same strom on a larger Hunter pulled for hull repair.
Again, she had a golf ball sized hole below the amidships chainplates at
the waterline. In this case, the interior layers of glass mat looked like the
end results of a grass fire...char black fuzz. They cut a 1 foot by 2 foot
section out around the damage. Granted, my hull was a solid layup, but I
thought of that lateral damage around the the hull and motor and decided not to
risk a third strike.
I live in Minnesota, USA. I am happy to attach the gounding wire from the
lightening rod on the mast each year.
Paul Brown
Procrastinator