100 Boating New Zealand
“At a cruise speed of five knots the old engine
used to run at about 2,200rpm, using two litres
an hour. To get to six knots I’d have to increase
that to 2,500rpm. It maxed out at 3,200rpm – for
very little gain in speed and a massive increase in
fuel consumption. But the problem was motoring
into rough seas – she just stopped dead.
“With the new engine, she does 3.7 knotsat 1,000rpm, 5.7 knots at 1,500rpm and at
2,000rpm she’s doing seven knots. So while the
new engine is probably using a bit more fuel, it’s
revving far lower.
“More importantly, the boat powers through
the seas now. This has made a huge difference in
how we use the boat. It’s affected our cruising
patterns and lifestyle – giving more flexibility to
make snap decisions.
“We can now tackle conditions – with
confidence – which we might have thought
twice about before. It gives us access to places
previously out of range, and we can now keep
up with friends when we go cruising – no more
lagging behind.”
Perhaps the most important benefit of
the transplant, he adds, is the one that isn’t
immediately obvious.
“It’s been a new, fascinating experience and
I’ve enjoyed it – I’ve grown with the boat. And
that’s significant because it’s extended our time
with her. It means we will keep Sweet Disorder
until we are no longer able to go cruising. We
won’t have to invest in a launch.” BNZABOVE The new sail-
drive slotted into the
existing mounting, but
a missing spline adaptor
caused a hiccup.
BELOW The new
engine’s footprint was
identical and simplified
the project.