LOOKING
47
PRACTICALLOOKING FOR TROUBLE
TO sublimely presume everything aboard
a ship is rosy when warning signs clearly
suggest otherwise is at best, naïve. At worst,
lack of immediate action can turn simple
repairs into major projects regardless of
where your boating interests lie. Following
are just a few signs of impending failure
deserving your full attention.HYDRAULIC STEERING
A common symptom of failure in
hydraulic steering systems is when the
wheel feels ‘lumpy’. It probably still steers
okay but wheel movements are no longer
smooth. This suggests that the oil level is
low and air pockets are forming signaling
its need to be topped up and possibly
‘burped’. Oil loss is typically from failing
ram seals that need replacing. Don’t be
caught without a spare set aboard.ENGINE OIL LEAKS
Engines do not experience the extreme
pressures of hydraulics however, after a few
thousand hours of service, shaft oil seals
can start weeping from one or both ends of
an engine, the most common point being
around the gearbox output shaft. This
often indicates engine misalignment with
increasing vibration an associated symptom,
especially if it is soft-mounted. Furthermore,if the propeller shaft bearing is dependent
on a modern bellows-type water seal, rather
than gland packing, there is every chance of
the bellows failing to the extent of actually
sinking a vessel.
Regardless of whether a misaligned engine
is soft or hard mounted, unbolt and draw
back the prop shaft coupling (Figure 1) and
check its fore-and-aft alignment with the
gearbox coupling. If they’re not true, realign
the engine using shims or micro screws until
the two couplings align perfectly, monitoring
every adjustment with a feeler gauge between
the coupling’s faces (Figure 2).WEEPING GASKETS
If an engine’s water cooling-pump weeps,
its cover gasket has probably split or even
disintegrated from old age. This seems
especially true of the paper-thin gaskets
used on impellor pumps. But whatever
type is involved, early intervention is
needed before the engine overheats and
possibly self-destructs. If your engine’s
circulating pump is gear-driven from
within the sump, leaking water might find
its way into the sump, a possibility made
obvious by it’s oil turning milky.
If a film of oil appears around an
engine’s tappet cover gasket, its bolts may
only need re-tensioning with due care not
to deform the cover in any way. If a minorALAN LUCAS
EXPLAINS HOW
TO RECOGNISE
THE SIGNS
OF IMMINENT
MECHANICAL
FAILURE AND
ACT PRE-
EMPTIVELY.
FOR TROUBLE