[PUP] Lightning preparedness

[Scott E. Bulger]

I've changed the name of this thread to better match the discussion

Dave observed:  I suspect that few of the newer Tier 3 engines will run if
subjected to
electrical under/overloading.

As always Dave makes outstanding points about the vulnerabilities of the
electronics on new engines.  My response was directly related to the
question about sensors and the ability of a engine to run in the event of a
sensor failure.  Of course there are innumerable things that can still bring
a motor to zero rpm.

Since this discussion started with a concern related to lightning, is it
possible that there are simple things we can do to give ourselves a fighting
chance in the case of a lightning strike?  In other words, if I had a Tier
II motor, would it make sense for me to isolate one of the house batteries
or additionally perhaps the bow thruster battery to insure I had an offline
spare?  Would simply flipping the battery switches provide enough isolation?
Should I shut down the genset or take the inverter offline?  Is the exercise
of simply thinking about these things enough to get each skipper to develop
a plan of their own?  It seems to me with all the uncertainty about managing
a lightning strike on the boat it might be difficult to come up with
definitive answers.

Yesterday I asked a knowledgeable person if he knew of any lightning strikes
on Nordhavns.  The answer was yes, and the boat had to be completely
rewired.  This affirms knowledgeable posts that in spite of having a system
installed in an attempt to deal with the problem, the results are going to
be unpredictable at best.

Some googling lead me to the following URL, which I found interesting:


At a minimum, lets start a list of things that be done to improve your odds
of staying functional in spite of a strike:  (perhaps we can add to this
list?)

Insure your personal safety
a.  Isolate crew from most hazardous areas, large metal fittings and the
vessel waterline
b.  Leave the flybridge, secure the deck to insure crew does not have to
become exposed during event

Keep the boat floating
a.  Reference all information on repairing a hull breach
	Retrieve and have available repair materials
	Advise crew who would become responsible for various duties prior to an
event
b.  Lower radio antennas or other appendages that might provide an
attractive path.
	NOTE:  Do not perform this duty if it exposes crew to dangerous conditions.
Lightning can proceed a front by miles.  This must be done well in advance
of an approaching system.

Maintain the ability to communicate
a.  Isolate at least one VHF radio.
	If your secondary installed VHF radio, remove power and antenna leads
(note:  When installing systems attempt to make this a very simple task,
i.e. install Transient Suppressors if possible)
	Remove hand held VHF radios from charging stands and place them in a
location away from the helm, isolated in a faraday cage if possible
b.  Isolate SATCOM systems if possible.  Turn off breakers for active
equipment, place hand held equipment in alternate location.
c.  Isolate SSB radios (and other technologies if appropriate:  Cell phones,
backup radar...)

Insure your ability to navigate
a.  Shut down and isolate redundant navigation systems
	Note:  Captain will exercise prudence to insure navigation is not
compromised
b.  Place backup laptop in isolated location, remove from charging systems
and docking systems if connected.
c.  Insure a working hand held GPS is available, batteries charged...
d.  update position on paper charts, if in use :)

Other thoughts?

Scott Bulger, Alanui, N40II, Seattle WA