Viper is a 14.75 inch/17 pitch, so it takes
a bit more grunt to get that prop moving,
whereas the lower pitch four blade
grabs a little less water, but more often.
While hole shot was better with the
four blade, its top speed was slightly
less at 31 knots at 5600rpm. Overall
performance was similar, but the four
blade is much more ‘certain’ in the water.
It has better grip and, as such, the boat
does not lose traction when running in
swells, which is very handy offshore.
The other interesting learning point was
that the Viper itself was pretty close
to optimum, giving the best speed and
cruising performance overall in calm
conditions, whereas the Cyclone was
better with heavy loads and in rough
conditions. So I have somehow ended
up with two propellers that optimise
performance in differing conditions.
It’s a case of horses for courses I guess,
but prop selection can make a huge
difference to a boat’s feel, economy and
hole shot.
Now back to the conundrum of why
the boat felt different. The 130 E-Tec
has the same leg and gear box as the
150 and, sitting in the same holes on thetransom, it replicates the underwater
footprint of the old 150hp motor. The
motor is roughly 20kg lighter and with
its lower profile (essentially with the
top two cylinders cut off), it carries its
weight lower down.
Overall, since the change of motor,
my boat sits better (feeling more sure
footed) in the water, it is better in a head
sea and, strangely, feels like a bigger
boat. After much deliberation, here is
my theory; taking 20kg off the stern
(noting that the Evolution has a pod as
well, so the motor hangs out a fair way)
has dropped the nose a fraction, which
in turn has driven the wide hips up front
further into the water. Thus the boat has
more hull in the water and therefore it
has better grip. Although we may only
be talking a few centimeters length
wise, this has made a big difference.
This increased contact with the water in
turn explains the lower than expected
economy, as the motor is driving more
hull through the water.
The Evolution was a great boat with
the 150 on it, but now strangely with
the 130 it’s become better to drive and
it feels like a bigger boat. Am I happywith the outcomes, given that one of
the desires (increased range) has not
been achieved? The answer is yes, as
somehow I have made a great boat
better on water. With the new motor
and the four-bladed prop the boat is
more certain and handles like a dream.
It’s interesting to note that a few of the
newer Evolution boats are coming out
sporting this motor and perhaps there
has been a realisation by others that
this not only saves a few bucks, but also
balances nicely!
Ultimately, the decision to repower
a boat needs to take into consideration
cost, the desired power and economy,
but also (and perhaps more importantly)
boat balance. Once this has been
considered, the last part of the process is
the selection of the right propeller.
For me, whether I selected an
Evinrude or a Yamaha came down to
the deal put forward at the time and my
previous experience with the brand. The
reality is that most of the major brands
make good motors, and at the end of
the day it is a matter of personal choice
and the deal available at the time you are
looking to purchase.Four blades or three? Both offer pros and cons Some lovely KG’s, courtesy of the new E-TEC 130uoS
th^ A
ustralian (^) An
(^66) rleg http://www.saangler.com.au