Mounting the hull unit on top of the installation trunk
The upper parts of the hull unit include the mechanical gantry, the hoist motor and the Motor Control Unit. The transducer shaft is supported by the gantry, and penetrates the mounting flange. The complete arrangement is mounted on top of the installation trunk.
Prerequisites
The shipyard must provide all necessary tools and manpower. The following specific items are required for this task.
•  Silicone grease
•  Locktite
•  Torque wrench
•  A crane capable of lifting the entire hull unit (Minimum load capacity is 2000 kg.)
The following specific items are required for this task. Items that are not included with the CS90 delivery must be obtained locally.
•  24 x Pin bolts/Mounting bolts M24x90
•  24 x Nuts M24
•  24 x Washers M24
•  O-ring 540-078749 (This item is included in the delivery.)
Note
The hull unit is heavy. Appropriate lifting equipment (lifting tackle, portable crane or ship’s crane) is required. Always use appropriate lifting equipment to minimize risk of personnel injury or equipment damages. Only certified equipment must be used.
Context
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As a general recommendation, the hull unit shall be oriented with the hoist/lower motor pointing aft. If this orientation makes it difficult to access the Motor Control Unit, the hull unit may be rotated during its installation to the most suitable direction.
The hull unit, transducer and transducer cable must be handled with care.
Note
•  The transducer is protected with a thick layer of foam to prevent damage during transport and hull unit installation. This protection must remain attached while the hull unit is being manoeuvred into the sonar room.
•  The transducer is covered with a thick red protective coating made of a special plastic type. The red protective coating is an vital part of the transducer. It is very important that neither this coating nor the internal parts of the transducer are damaged during the handling, installation or cleaning. Any holes and/or scratches in the transducer surface will allow water to penetrate the transducer. If a leak occurs, the transducer must be replaced.
•  The top mating surface of the installation trunk must be protected with a blind flange or wooden cover at all times until the hull unit is installed. It is very important that this surface is clean and undamaged, because it must be watertight after the hull unit has been installed on top of the installation trunk.
•  The Motor Control Unit must never be physically dismounted from the hull unit gantry.
A dedicated O-ring is provided with the CS90 delivery. This O-ring ensures a watertight connection between the installation trunk and the bottom of the transducer shaft sleeve. During the installation process, make sure that this O-ring is kept safe from damage, and that the top of the installation trunk is kept clean, smooth and without physical damage such as scratches or dents. Proper O-ring lubrication must be applied before the hull unit is mounted on top of the installation trunk.
Procedure
1 Lift the Hull Unit (with the transducer protection still in place!) and place it vertically over the installation trunk.
While lifting, make sure that you do not damage the delicate parts of the hull unit.
Note
Make sure that you keep the transducer safe, and the transducer cable and connector dry. Watch these carefully to prevent these delicate parts from being damaged, stuck or hooked on to protruding objects while manoeuvring the hull unit into the sonar room. Do not remove the transducer protection (the thick foam) until just before the hull unit is lowered onto the installation trunk.
2 Remove the blind flange from the top of the installation trunk.
A blind flange is mounted on the installation trunk for protection if the trunk is provided with the CS90 delivery.
Store the blind flange in the sonar room for possible future use.
3 Check the top of the installation trunk. Verify that:
a Make sure that the rubber gasket on the top of the installation trunk is not damaged.
b Make sure that the surface of the installation trunk is clean and free from grit or other damaging particles.
c Make sure that the top of the installation trunk has not been damaged, and that it is smooth and even without physical scratches or dents.
4 O-ring:
a Clean the O-ring groove and inspect the O-ring.
b Apply a thin film of silicon grease on the O-ring.
c Install the O-ring.
5 Remove the transducer protection.
6 Lower the Hull Unit carefully onto the installation trunk.
Important
The transducer is covered with a thick red protective coating made of a special plastic type. The red protective coating is an vital part of the transducer. It is very important that neither this coating nor the internal parts of the transducer are damaged during the handling, installation or cleaning.
7 Align the mounting holes carefully.
8 Mount and tighten the relevant nuts and bolts.
First, tighten all the nuts to finger tight. Then work alternately on opposite sides of the construction.
Use the following final maximum torque: 470 Nm