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.

The vessel is in dry dock. The ST90 system is turned off. The following tools and consumables are required:

  • Personal protection
  • Fresh water
  • Plastic brush
  • Mild synthetic detergent
  • Piece of wood or plastic without sharp corners

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.

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. Make sure that you have sufficient height between the hull and the dry dock floor.
  3. Lowering the transducer:
    1. Use a spanner to open the door on the Motor Control Unit.
      Warning:

      High voltages are used. This equipment must be serviced only by qualified personnel familiar with high-voltage equipment and the potential hazards involved. Failure to observe this precaution could result in bodily injury. You may be exposed to electric shock. Read and understand the applicable first aid instructions related to electric shock.

    2. Locate the Motor Protecting Switch (S301).
    3. Deactivate the Motor Protecting Switch (S301) by pressing the operating handle to OFF.
    4. Locate the hand crank inside the Motor Control Unit.
    5. Remove the hand crank from its storage position.
    6. Remove the plastic plug on the top cover of the hull unit.
    7. Mount the hand crank onto the stub shaft through the hole in the top cover.
    8. Locate the brake release screw on the motor.
    9. Use an 4 mm Allen key to rotate the screw clockwise until the motor brake is released.
    10. Turn the crank until the transducer is fully lowered.
  4. Allow for sufficient access to clean and inspect the entire surface of the transducer.
  5. 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.

  6. Allow the transducer surface to dry.
  7. Do a thorough visual inspection 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 Discovery support for advice.

  8. Hoisting the transducer:
    1. Mount the hand crank onto the stub shaft through the hole in the top cover.
    2. Turn the crank until the transducer is fully retracted.
    3. Loosen the brake release screw to engage the motor brake.
    4. Check with the hand crank to ensure that the motor brake is engaged.
    5. Remove the hand crank from the stub shaft, and mount it in its storage position in the Motor Control Unit.
    6. Activate the Motor Protecting Switch (S301) by pressing the operating handle to ON.
    7. Make sure that the Hoist/Lower Switch is set to REMOTE.
      Note:

      For normal operation from the Operating Panel, the switch must be set to REMOTE.

    8. Close the door on the Motor Control Unit.