Cleaning the hull unit
The hull unit has normally been exposed to a salt atmosphere. Prior to storage and/or shipment, it must be thoroughly cleaned to prevent corrosion.
Prerequisites
In order to clean the hull unit, you will need relevant tools and detergents.
Context
For all practical purposes, the hull unit comprises to separate areas; the “wet parts” and the “dry parts”.
•  The “wet parts” include the lower part of the transducer shaft, the installation trunk, the bottom of the mounting flange, the zinc anodes and the transducer. These parts are all exposed to the sea.
•  The “dry parts” are the rest of the hull unit, all contained inside the hull. This includes the electric motor and the Motor Control Unit.
A transducer must always be handled as a delicate instrument. Incorrect actions may damage the transducer beyond repair.
Observe these transducer handling rules:
•  Do not activate the transducer when it is out of the water.
•  Do not handle the transducer roughly and avoid impacts.
•  Do not expose the transducer to direct sunlight or excessive heat.
•  Do not use high-pressure water, sandblasting, metal tools or strong solvents to clean the transducer face.
•  Do not damage the outer protective skin of the transducer.
Procedure
1 Wash the “wet parts” of the hull unit using a high-pressure hose and copious amounts of fresh water.
Caution
Do not use direct the high pressure water directly towards the transducer. Observe the handling rules!
2 Ensure that all traces of mud and marine growth are removed.
Use a wooden or plastic scraper to remove persistent growth, barnacles etc.
3 Wipe off the external surfaces of the “dry parts” of the hull unit using a damp lint free cloth and a mild detergent.
Note
Do not use excessive amounts of water. The “dry parts” of the hull unit includes parts that are not water tight.
4 On completion, dry the unit thoroughly.
5 Inspect all surfaces for signs of corrosion, flaking, bubbling paint, stains etc.
6 Clean damaged or suspect areas, prepare and preserve these areas using the correct preservation mediums.
7 Wipe clean all exposed cables, and check for damage.
If a cable shows signs of wear or ageing, contact Kongsberg Maritime for advice.
8 Secure and protect loose parts.
9 If the hull unit shall be sent to storage or shipped, spray it externally using a corrosion inhibitor (for example a light oil) prior to packing.
10 If relevant, place a suitably sized bag of desiccant material (silica gel or similar) into the to storage/transport box to keep the components as dry as possible.