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PRACTICAL
THIS MONTH THE AGULHAS CURRENT • G4 FOILING CAT • HANDLING LIGHTNING STRIKES • POSTRACE DEBRIEFS
SPECIAL REPORT
CHRIS TIBBS ON COPING WITH POWER FAILURE
complete power failure mid-ocean is
thankfully rare, and it is usually (but
not always) the charging system that
fails rather than batteries.
Nowadays it is unusual to find yachts with
only one battery bank and without a dedicated
engine start battery. Many of us have known
selector switchers that can be left in the
wrong position, so I prefer a set up where
it’s impossible to link batteries like this. One
boat I looked after had a paralleling switch to
temporarily link all the batteries should the
engine start battery not be up to the job. This
had to be held in place so it could not be left on;
we use a simpler solution and carry jump leads.Long distance cruising yachts will usually
have more than one means of charging the
batteries and the majority of cruisers have solar,
wind vanes, or hydrogenerators to back up the
engine. While these may go through one single
regulator, each system will often have its own
regulator for some redundancy and backup.Get your priorities right
If you’ve lost power production you need to
reduce consumption and prioritise. Top of
my list is navigation lights – a masthead LED
tricolour draws around 0.3A which, even on a
tropical passage with long nights, is less than
3.5Ah. It also has the added advantage oflighting up the Windex so we can reduce the
time we use electrical instruments.
The compass light is also important and
while it may draw as much or more than the
tricolour, steering at night is difficult without
this reference point.
On an ocean passage like the Atlantic
you don’t need to know your position at all
times – once or twice a day is adequate. This
means chartplotters can be turned off, and the
GPS used only a couple of times a day to log
position. A handheld from the grab bag can be
used for this, as can the handheld VHF, as long
as you have enough spare batteries.
High on the list of priorities must be starting
the engine in case of an emergency. If all
the batteries are connected together, as in
Seraphina’s case (see right), it may be possible
to split them mechanically and use the solar
panel (or petrol generator) to charge the engine
start battery and keep it isolated for emergency
use. I’d also look at which batteries were inA
Tor Johnson