Inspecting and cleaning the transducer face
Marine growth (biological fouling) on the transducer face reduces the performance. For this reason, it is important to keep the transducer face clean. Every time your vessel is in dry dock, you must remove the marine growth. At the same time, you must inspect the transducer closely for physical damage.
Prerequisites
The vessel is in dry dock. The SU90 system is turned off. The following tools and consumables are required:
•  Personal protection
•  Fresh water
•  A mild synthetic detergent and a plastic brush
•  A piece of wood or plastic without sharp corners
•  Citric acid (<50%) (only if required)
Two persons are needed to do the task.
•  One person must stay in the sonar room to operate the hull unit.
•  One person must stay in the dry dock, under the hull, to make sure that the transducer is not lowered too far down.
Proper oral communication must exist between the sonar room and the dry dock personnel.
Context
During normal use, the transducer is subjected to biological fouling. If this marine growth is excessive, it will reduce the overall performance of your system. Whenever opportunity arise, typically when the vessel is dry-docked, the transducer face must be cleaned for shells and other marine growth. It is important to check the transducer for physical damage. Any cracks, fractures or holes in the red protective coating may result in a water leak, and a leak may cause irreparable damage to the transducer.
A transducer must always be handled as a delicate instrument. Incorrect actions may damage the transducer beyond repair. A physical blow to the transducer face may easily damage one or more elements. Observe these transducer handling rules:
•  Do not activate the transducer when it is out of the water.
•  Do not handle the transducer roughly. Avoid impacts.
•  Do not expose the transducer to direct sunlight or excessive heat.
•  Do not damage the outer protective skin of the transducer.
•  Do not use high-pressure water, sandblasting, metal tools or strong solvents to clean the transducer.
•  Do not step on the transducer cables.
•  Do not damage the transducer cables. Avoid exposure to sharp objects.
Procedure
1 Make sure that all power to the hull unit is disconnected.
2 Use the hand crank to lower the transducer.
3 Allow for sufficient access to clean and inspect the entire surface of the transducer.
4 Remove biological fouling carefully using a plastic brush, a suitable synthetic detergent and fresh water.
Biological material which is strongly rooted in the substrate can be removed carefully with a piece of wood or plastic. If required, you can also use citric acid. Apply, leave it working for several hours, and rinse thoroughly with fresh water.
Be careful so that you do not accidentally make cuts or inflict other physical damage to the transducer face.
Note
Do not use high-pressure water, sandblasting, metal tools or strong solvents to clean the transducer. Do not damage the outer protective skin of the transducer.
5 Allow the transducer surface to dry.
6 Do a thorough visual check of the transducer. Inspect it closely for any signs of dents, cracks, fractures or holes.
If you find suspicious damage, take high resolution photos that show the damage, and contact Kongsberg Maritime support for advice.
7 Apply anti-fouling paint as described in the dedicated procedure.
Note
Because some paint types may be aggressive to the polyurethane in the transducer, consult our list of approved paints. The list can also be found on our website.
8 Use the hand crank to hoist the transducer.