Verifying the quality of the installation
Once the installation trunk and blister have been installed, a quality inspection must take place. The purpose of the inspection is to makes sure that the installation trunk has been installed correctly, and that the hull unit can be mounted on top of it.
Prerequisites
Neither tools nor instruments are required.
Context
The installation trunk must be mounted so that it remains vertical during normal operating conditions.
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. It must be watertight after the hull unit has been installed.
Objects protruding from the hull will generate turbulence and flow noise. This will reduce the overall performance of your system. Protruding objects may be zinc anodes, transducers or even the vessel's keel. Holes and pipe outlets are also important noise sources, as well as rough surfaces caused by bad welding. Even traces of sealing compound, sharp edges, bolts or empty bolt holes will create noise.
Procedure
1 Write down the key measurements.
This is for future reference.
•  Horizontal distance from the keel to the centre of the installation trunk
•  Height from the bottom of keel to the top of the installation trunk
•  Total height of the installation trunk (with optional blister)
2 Do a close visual inspection of the physical properties of the installation trunk and the way it has been installed.
Refer to the applicable requirements.
a Make sure that the upper surface of the installation trunk is level, undamaged and clean.
b Make sure that the installation trunk has been properly stiffened in both the fore-and-aft and athwartship directions by means of strengthening knee plates.
c Make sure that the installation trunk has been properly braced to the hull plating and the surrounding hull frames.
3 Do a close visual inspection of the blister and the hull plating close to the installation trunk.
Check for any kind of objects that may cause noise.
4 Make sure that all surfaces are protected with a high quality coating.
5 Make sure that the inside of the installation trunk is also protected with coating.
6 Fill in the result tables.
Result
Horizontal distance from the keel to the centre of the installation trunk Height from the bottom of keel to the top of the installation trunk Total height of the installation trunk (with optional blister)


Requirements Results
All measurements are made and the results are written down.
The top of the installation trunk is in parallel with the water line.
The top surface of the installation trunk is clean without sand, dust or any other destructive particles. Is is even and smooth without scratches, dents or other physical damage.
The installation trunk has been properly stiffened in both the fore-and-aft and athwartship directions by means of strengthening knee plates.
The installation trunk has been properly braced to the hull plating and the surrounding hull frames.
The hull plating surrounding the installation trunk is even and smooth without protruding objects that can cause noise.
The gasket is not damaged.
All surfaces (including the inside of the trunk) are protected using a high quality coating.
Date and signature:
Further requirements
If the inspection reveals errors, inaccuracies or unfortunate dispositions related to units, devices or cables, use the Installation remarks form to document these. If necessary, write a full report, and attach high resolution photos.