Alamarin Jet AJ 160, Operation And Maintenance Manual

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Operation and Maintenance Manual
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Version 1.5
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3.4. Raw Water Cooling
The jet comes complete with the possibility to connect the engine cooling water (cf.
Figure 3.4-1). The engine does not need a separate water pump. However, if the cooling
water is taken with a separate pump, the jet’s raw water line is stoppered.
At the beginning of the line, there must be a tap with which the line can be shut
temporarily for example during cleaning of the filter or other maintenance.
3.5. Corrosion Protection
The raw materials used for manufacturing the jet parts are mainly aluminum, acid-proof
steel, and plastic.
Materials that have different electrochemical properties can form a so-called galvanic
couple while they are in electrolytic fluid (salt water). A galvanic couple forms an
electric circuit, because the materials have different inherent voltages. This in turn leads
to electron movement and corrosion of the weaker material. Cathodic protection is used
to try and prevent the propagation of galvanic corrosion. Cathodic protection means
introducing into the same circuit a third material, the electrochemical properties of
which are weaker.
3.5.1. Cathodic Protection
The jet is protected from galvanic corrosion with passive cathodic protection. Every
critical aluminum casting has its own zinc anode. In figure 3.5-1 are shown the places of
the anodes.
Figure 3.4-1
1. Raw water connector (G 3/4
”)
2. Tap
3. Filter
4. Raw water intake
3
1
2
4