Simrad NX40, Руководство по установке и эксплуатации

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Simrad NX40/45 Installation and Operation Manual 55
13-5-2 Water speed and ground speed
A paddlewheel sensor and a pitot sensor measure
water speed, the boat speed through the water. A GPS
measures ground speed, the boat speed over the bottom
of the water. If there is a current, then these speeds will
be different, and the log, trip log, economy and range
will be different, as shown below.
Water speed is better for measuring the boat’s potential
performance, Ground speed is better for going to a
destination because it takes currents into account.
When the current is from ahead, ground speed is less
than water speed.
For Example 1
If the boat travels for one hour, uses 3 gallons of fuel per
hour and has 50 gallons of fuel left:
When the current is from behind, ground speed is more
than water speed.
For Example 3
If the boat travels for one hour, uses 3 gallons of fuel and
has 50 gallons of fuel left:
13-6 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 for
the conditions.
13-6-1 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
Example 4:
A (water speed) = 10 knts.
B (current) = 4 knts at 45º.
Gives a ground speed of
about 13 knts.
Example 3:
A (water speed) = 10 knts.
B (current) = 4 knts.
Gives a ground speed of 14
knots.
Example 2:
A (water speed) = 10 knts.
B (current) = 4 knts at 45º.
Gives a ground speed of
about 8 knts.
Example 1:
A (water speed) = 10 knts.
B (current) = 4 knts.
Gives a ground speed of 6
knots.
Speed Log Economy Range
Using water
speed
10 knts 10 nm 3.3 nm/gal 165 nm
Using ground
speed
6 knts 6 nm 2.0 nm/gal 100 nm
Speed Log Economy Range
Using water
speed
10 knts 10 nm 3.3 nm/gal 165 nm
Using ground
speed
14 knts 14 nm 4.7 nm/gal 235 nm