Alamarin Jet AJ 160, Operation And Maintenance Manual

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Operation and Maintenance Manual
1414
Version 1.5
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The centre position of the reversing deflector corresponds to gear’s ”idle” position; even
though the drive is on, the boat stays still. The centre position is not absolute, it depends
on the power of the jet flow
. Finding the centre position is done by testing during the
first driving hours.
When moving
at low speeds, the reversing deflector is used to control the boat’s speed
.
Because the engine is being run at 1200-1800 rpm to enhance steering, the boat may
travel faster than desired. In this case the deflector is lowered in front of the jet flow
to reduce the thrust directed towards the driving direction. Steerability remains good
however.
At high speeds, the deflector is not used to reduce speed. Instead, speed is controlled
with engine revolution.
It is possible to turn the boat in place when the deflector is in centre position. When the
nozzle is turned to the desired direction, the boat rotates about its central axis.
When reversing, steering is inversed in comparison to driving forward . If you want to
turn the boat to the left, the wheel must be turned to the right. A good mnemonic is that
the boat’s bow always turns in the same direction as the wheel.
When fast turns are needed, the engine revolutions are not reduced, but instead the turn
is done through combined motion of the nozzle and the deflector.
Figure 2.3-1
2.3. Operating in Shallow Water
The jet boat can be used in very shallow water, but it must be taken into account that
especially on high revolutions the suction power of the intake is high (cf. figure 2.3-1).
Loose objects may get sucked into the intake screen and small objects wash through the
jet. Stones may cause damage. In sandy conditions wearing inevitably takes place. The
maintenance procedures required by a worn impeller are described in the maintenance
section of this manual. See Adjusting and Fitting the Impeller, page 24.