Engine Loading: The Key to Performance Understanding engine loading is critical to
achieving maximum performance.
To get the necessary loading information it is necessary to
Sea Trial the vessel. These trials are best done
on a nice day with no significant wind or waves at about 80% normal
full load (weight) with the synchronizer off. There are two ways to
measure engine loading. On gasoline engines or diesel with mechanical
governors engine loading is measured as the Top RPM Wide Open
Throttle that can be achieved.
The top rpm's should be read with either a phototach or off a quality
digital tachometer.
Accurate readings are critical. More modern diesel engines are computer
controlled and electronically governed.
For these engines it is necessary to measure the Percent Load
at Wide Open Throttle.
This information allows us to establish where, on the power curve,
the propellers are loading the engines.
Too high an rpm or too low a percent load indicates that the propellers
are not utilizing all the horse power available.
The vessel will be accelerating slowly at a perceptibly high rpm and
once at speed the engines will seem to be running fast for the speed.
Too low a top Rpm or too high a percent load indicated that the propellers
are overloading the engines and the engines are not being allowed
to produce the power they are capable of producing. In this situation
the engines would be running hot and using too much fuel.
Additionally, idle speed will be unacceptably high and maneuvering
will be difficult because the vessel will have
the tendency to “jump” when put in gear.
Boating
Magazine
“We picked up 1 mph at top
the top end and nearly 3 mph at the boat’s cruising
speed of 1900 rpm. In addition, we were able to run similar
speeds at lower rpm, which helped fuel consumption.”
Power
& Motor Yacht
“Computerized scanning can make your props
more efficient and your boat perform better.”
Shallow
Draft
“Ignoring the propeller on
today’s sophisticated vessels is ignoring the most important
piece of equipment on your vessel.”
Marine
News
“Combined with vessel performance and
engine loading information the Prop Scan EPS software can
calculate changes that will decrease propeller slip and match
engine loading requirements thus increasing vessel performance.”
Contact WildCat Props!
Custom propeller configurations are also available on request. Should you
require assistance in selection of a new propeller suited to your vessel,
restoration-repair of your existing propellers or prop tuning-maintenance
please contact WildCat Props.
Read How WildCat Props Exceeds the Expectations
of Our Customers!
I wanted to finally thank you for your help and expertise in resizing the
wheel for my Duffy '38 which was extended to '42 and repowered. With the
info you were provided with your recomendations were right on. With the
additional light cup you recently added I am sure things will be "quieter"
than ever. Most importantly, you have always been very generous with your
time on the phone helping educated me on the subject of propeller hydrodynamics.
