Fuel Consumption Curves - NorthStar EXPLORER 557 Installation And Operation Manual

10-6 Fuel consumption curves

A fuel consumption curve shows fuel consumption (fuel used per unit of distance travelled) and boat
speed as a function of engine RPM. Fuel consumption curves require engine RPM, which requires
SmartCraft™ to be installed. Fuel consumption curves are powerful tools for assessing boat performance
in different conditions and for helping you to run at the most economical speed and trim for the
conditions.
10-6-1 Making a fuel consumption curve
To make a fuel consumption curve you will need
to run the boat in a straight line for about 15
minutes using the engine's full RPM range. For
your first curve, choose a calm day with light
wind and little current; have a typical load and
a freshly cleaned hull. Later, you can make fuel
consumption curves for different boat, weather
or sea conditions. Compare these with your
first curve to see how your boat's performance
changes with conditions.
Making a curve
1 Start running the boat in a straight line.
2 Choose a speed source for the curve (see
section 10-5-1). Normally choose Water speed
to measure the boat's potential performance.
3 Press twice, then select Fuel.
4 Select Fuel consumption curve, then
select New.
5 Enter the comfortable maximum RPM you
know you can achieve for the engine rather
than the maker's value.
6 The 557/567 then asks you to set the
minimum RPM. Set the throttle to idle; on a
multi engine boat set all engines to about the
same idle RPM.
Now, do not change the engine speed.
Wait for about 60 seconds for the boat to
stabilise, then press
computer records the data.
. Wait while the fuel
Northstar Explorer 557/567 Installation and Operation Manual
7 The 557/567 then asks you to set the throttle
to achieve a vessel RPM. On a multi engine
boat set all engines to about the vessel RPM.
When the engine RPMs are correct, the Vessel
RPM box will turn green.
Now, do not change the engine speed.
Wait for about 60 seconds for the boat to
stabilise, ensuring the Vessel RPM box stays
green. Then press
computer records the data.
8 The 557/567 repeats the above step to record
data up to the maximum RPM. Then the
557/567 asks if you want to save the curve.
Select Yes. The fuel computer asks for a name
for the curve. Change the default name if
required. Then press
stores the new curve.
Note To interrupt making the curve at any time,
press .
. Wait while the fuel
. The 557/567
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