Defining the middle position of the transducer
The hull unit provided with the CS90 is designed to lower the transducer down below the ship’s hull when the CS90 shall be used. When the CS90 is switched off, the transducer is hoisted for protection. The CS90 allows you to define a middle position for the transducer.
Prerequisites
The physical properties of the hull unit installation are known.
The correct type of hull unit is selected.
The vessel is berthed or at sea.
Context
The middle position is not a fixed length. The physical middle position depends on which type of hull unit you are using with the CS90.
Retracting the transducer to a middle position may be useful if you use the CS90 simultaneously with other sonars. A higher position will permit you to increase the vessel speed. If you operate in very shallow waters, you may also reduce the risk of hitting bottom. However, placing the transducer immediately under the hull may increase the flow noise.
Caution
If the transducer hits larger objects or bottom, the transducer shaft may be bent, or - in worst case - it can be broken off. A broken transducer shaft will cause water leakage through the top of the shaft. If you suspect that the transducer shaft is seriously damaged with holes, do not retract the transducer to its upper position.
To prevent serious damage to the vessel or the vessel stability, you must have a water pump and a warning system in the sonar room.
Select the middle position carefully. The position is normally selected to place the transducer just under the keel, but low enough to prevent echoes from the trunk. Once the position is selected, make sure that the system protection functionality does not inhibit transmission.
Image
Procedure
1 Make sure that you have sufficient water depth below the keel before you lower the transducer.
2 Open the Operation menu.
3 On the top bar, select Hull Unit to access the control settings.
Image
4 Select [+] and [] to adjust the middle position.
5 Open the Setup menu.
6 On the Setup menu, select Installation.
Image
Observe that the Installation dialog box opens. This dialog box contains a number of pages selected from the menu on the left side.
a On the left side of the Installation dialog box, select System Protection to open the page.
b Make sure that the upper limit of the Tx Inhibit Hull Unit Position does not exceed the middle position.
c Adjust the setting if it is necessary.
d At the bottom of the page, select Apply to save your settings.
e Close the Installation dialog box.
7 Lower the transducer to its middle position.
8 Start normal operation.
9 Make sure that the CS90 operates normally without transmitting into the installation trunk.