iXBlue GAPS - Corrosion; Principles

GAPS - User Guide
3.2.1.4 Corrosion
GAPS is an electrical equipment that goes underwater. It may be submitted to differences of
potential that can lead to the corrosion of the mechanical structure of the antenna.
It is your responsibility to minimize the differences of potential between the GAPS antenna
and the surrounding structures. The GAPS antenna must benefit from the electrolytic
protection of the vessel.
Contact iXblue technical support if you notice corrosion damages on the 8 titanium screws
holding the GAPS or directly on the antenna housing (ex: blisters of the paint).
3.2.2 PRINCIPLES
H1
When you set up GAPS on the ship, it is recommended to set the hydrophone H1 towards the
bow of the ship. Positioning H1 towards the bow generates more drag but, in this position, the
acoustic noise is reduced.
Electrical
Insulation
In case GAPS is fixed on metallic plates of different materials (electro-chemical potential,
aluminum for example) it is necessary to electrically insulate it in order to avoid any electro-
galvanic reaction that will result in structure corrosion and GAPS acoustic array fouling.
Location and
Dimensions
There must be enough space for the wire way on the connector side of GAPS. GAPS is fixed
using the eight M8 screws.
The torque to mount the eight M8 screws must be from 15 Nm to 17 Nm. There is no need to
use Loctite glue or similar.
see Appendix Lthe dimensions of the antenna on the mechanical drawing.
Misalignment
You can intentionally tilt the GAPS antenna in any directions as long as you precisely measure
the tilt angles. The angle values have to be entered into the Web-based User Interface during
the configuration of the antenna. 4.3.
Antennas
exchange
If you wish to exchange one acoustic antenna by another one on the same GAPSBOX, follow
the procedure below:
1. Turn OFF the GAPSBOX.
2. Exchange the GAPS acoustic antenna.
3. Turn ON the GAPSBOX.
4. Wait one minute.
5. Turn OFFand ON the GAPSBOX
38 MU-GAPS-AN-005-H - November 2019