TWL: Lightning
Would you say that there is no way to protect your electronics from a
direct hit.
No.... I would say that there's no practical way. Unplugging every unit on
the boat from its antenna and power source will go a long way toward
protecting electronics from spike damage, but what do you do about the
batteries, bilge pumps, starter motors, chargers, inverters, air
conditioners, active lightning protection devices, etc, etc, etc.
Is it easy to avoid them with quality radar? I know rain is easy to spot,
but what about the lightning bolts?
You have to understand that the vast majority of strikes that do occur happen
on boats that are at their mooring and often unattended. Since boats in
general spend an average of 26 days a year with anyone on board, you can see
the logic in that. Even full time cruisers are underway an average of 75 days
a year.
Al Golden
International Marine Insurance Services
1-800-541-4647
Al - It does take a little doing but there are pretty good reports of
amateur radio operators achieving very good results even with direct hits.
The antenna itself is probably scrap but the 5 or 10 Kilobucks of amateur
radio survives. In my personal case I believe that I could survive a direct
hit on my 20 meter beam without radio damage. I have a very robust
grounding system involving 1 inch copper cable and the reinforcing rods
within the base of the antenna. I suspect the aluminium beam itself would
be toast but the radios and computers would probably survive. I hedge only
because lightning can be treacherous and sneak through the power lines or
telephone lines and find a way past my heavy system. Unlikely here though
as everything is buried relatively deeply underground - It would have to be
one of these jump from the tower to the basketball hoop to the light
stantion into the house wiring. Unlikely but not completely impossible.
The commercial radio stations in the South live with almost daily hits.
Another point demonstrating lightning is not impossible to contain. Note
however they do play a catch 22 game in that business. If the station is
damaged by lightning - which does happen rarely - they claim the lightning
system was not properly installed.
Boats are tougher but not impossible. Sailboats are much simpler than power
boats. In both though the key is a direct connection with a very low
impedance to the water from a high and sharp point. Secondary protection on
antennas should also be implemented as well as shortable connections on
antennas.
I don't think you can get 100% protection anywhere - but high 90's is
probably possible on a boat.
Jim
-----Original Message-----
From: owner-trawler-world-list@samurai.com
[mailto:owner-trawler-world-list@samurai.com]On Behalf Of AL GOLDEN
Sent: Saturday, August 26, 2000 2:14 PM
To: Blind.Copy.Receiver@compuserve.com
Subject: TWL: Lightning
Would you say that there is no way to protect your electronics from a
direct hit.
No.... I would say that there's no practical way. Unplugging every unit on
the boat from its antenna and power source will go a long way toward
protecting electronics from spike damage, but what do you do about the
batteries, bilge pumps, starter motors, chargers, inverters, air
conditioners, active lightning protection devices, etc, etc, etc.
Is it easy to avoid them with quality radar? I know rain is easy to
spot,
but what about the lightning bolts?
You have to understand that the vast majority of strikes that do occur
happen
on boats that are at their mooring and often unattended. Since boats in
general spend an average of 26 days a year with anyone on board, you can see
the logic in that. Even full time cruisers are underway an average of 75
days
a year.
Al Golden
International Marine Insurance Services
1-800-541-4647