Re: [PUP] Passagemakers under power, and sails
<Scott wrote: I think the FUD around these motors will die down as
experience is built. There will be stories of failures, but that's also
true with none electronic varieties as well.>
If the Lugger tier 2 engines can do this great. I recently had an experience
with the 575 HP Volvos and if you don't have 24 volts they won't run,
period. No amount of bypassing nor replacement will work around this. Plus
the 24 volts must be in the range that the ECU's will accept...not to high
not to low.
I suspect that few of the newer Tier 3 engines will run if subjected to
electrical under/overloading.
Next time you are on your boat and the engine is running flip the battery
switch to the engine to the off position. See if it stays running. This is a
good test and one the Volvo's fail. BTW make sure the alternator has a Zap
Stop or similar diode across the output of it will be zapped.
This is a pretty simple test and one the factory techs are not going to like
no matter what the marketing techs reps tell you.
If you have electronic controls do the same with their power source. See if
they reboot/restart when you re-apply power. This too can be a problem with
some systems.
My point is that a car with a dead battery doesn't run not does a combine
nor an OTH truck. They all need power and today that power must be of much
better quality than in the past.
Cranking an electronic engine with a low battery that gets to 10 volts
during cranking won't allow the engine to start as the computers generally
need 11.5 to work. Run your start batteries down to 11 volts.....then try to
start the engine. It will crank but doubtfully start.
When the fan is blowing the s..t around isn't a good time to find out all of
these things. Better to subject the systems to a bad day at sea while still
tied to the dock, IMHO.
As always YMMV,
Cheers
Dave & Nancy
Swan Song
Roughwater 58
Caribbean Cruise '07
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
Well, I thought that's what I said. Protect the crew - that's feasible by
creating a cone of safety using the mast. There is general agreement that
this has a high probability of success.
Equipment protect for gear that is connect to any electrical or bonding
system is futile. Depending upon the nature of the strike and the consequent
EMP, it is unlikey anything will survive. Rewiring the boat is a little
unusual, but depends upon doing a real analysis. Example: My RG8U VHF cable
looked perfect and passed a continuity test. However, a buddy at EG&G wanted
to take sections of the cable and place them under an electron microscope.
The cable was in fact damaged by heat.
Therefore, Scott, your idea of having disconnected spares is the best
civilians can do. Spare batteries, a GPS, and VHF any other spares you need
for survival and that you can afford, should be stored aboard. I think I saw
a Faraday cage instrument panel built by Palmer Johnson for a Mason (PAE)
sailboat. It was a complex, screened, metal framed structure and I can only
wonder if it worked. On another list, it was pointed out that most
electronic engine have a "limp home" mode. Whether that mode is available
after a lightning strike was not mentioned.
One point not previously mentioned is the physical damage that can occur.
For example, I know several sailboat owner whose thru-hull depth transducers
blew out of the boat. Two boats were manned and survived while the third was
unattended in its slip and sank. It is likely that these were direct
strikes.
When Navy CICs were run by DG mini computers, every component (that I could
see) was wrapped in tantalum foil. The mini itself was residing in a
thick-walled metal safe that formed its outer casing. There was a lifting
ring built into the top of the box. I don't know if the Navy uses that
technique anymore and several novels have suggested that a battlegroup could
go blind from nuclear EMP. I'd like to think that they can survive lightning
strikes without damage.
My personal experience was that electronics not connected survived a near
strike while everything connected was damaged. One thing I learned was not
to allow anything to be repaired because there are incipient failures that
will emerge long after the initial repair - I know this! Datamarine, for
one, would not do repairs on lightning damage - they were right.
Ron Rogers