Choice Of Hull Equipment - BEN Marine ANTHEA Notice D'utilisation Et D'installation

2. CHOICE OF HULL EQUIPMENT

1. According to vessel size
- Hull-fittings with valve (48.1 RVI - 48.1 RVB)
are used on all types of vessels
- Hull-fittings without valve (48.1 RB - 48.1 RA - 48.1 RBL - 48.1 RI)
are used on:
. 500 toners maximum
. Fishing ships not longer than 45m
. Yachts
2. Hull fitting cannot be used in dangerous compartments (fuel, hydrocarbons, chemicals).
3. Hull strength must be checked before installation of hull fitting.
4. Hull fitting must be installed in compliance with the specifications of the ship
classification company.
5. Power supply wiring must comply with the specifications of the ship classification
company.
Sensor location
The flush sensor must be installed in the foremost area of the vessel, when possible in a
perpendicular position in the lower section of the bulb on the keel line. Deviation from the
perpendicular measured in relation to the vessel's center line is not to exceed 5°.
In relation to the port/starboard yaw axis, deviation to a maximum of 30° may be permissible
in particularly favorable conditions.
The installation position is to be at least 0.5m from echo sounder transmitter and similar
devices;
The sensor must be positioned at least 10m away from corrosion protection electrodes. The
maximum AC voltage component of the supply voltage of active corrosion protection
electrodes is not to exceed 20mV eff.
The flat sensor surface measures the water speed along the hull. This measured speed is not
equal to the vessel's true speed. Measured speed is lower than vessel's speed. At vessel's
extreme fore, near true speed is obtained, but towards the aft of vessel speed value differs.
The area along the hull where speed is different from vessel's speed is called the "boundary
layer". Its thickness increases from fore to aft. The main cause is water running along the hull,
which decreases up front. Because of the hull profile, hydrodynamic penetration coefficient is
minimum in the fore.
Speed does not depend on fouling of the hull located in the boundary layer. Therefore, the
ratio of the vessel's speed and measured speed is constant.
The sensor must be located near the bow, as far forward as possible. It must always remain
immerged (if the sensor emerges occasionally, this can cause a short disturbance which
doesn't effect the total distance information).
In order to protect the sensor against docking maneuvers, it is recommended to weld two
strips on both sides of the sensor close to the hull-casing flanges. In order to avoid
hydrodynamic disturbances, it is strongly suggested to profile these strips. Their dimensions
will be calculated depending on the desired protection.
This document is Avantix property and cannot be copied or transmitted without the company's authorization
97MU001-F
ANTHEA OPERATION AND INSTALLATION MANUAL
9-B