Page 10 of 48
Date: 2021-12-10
Date: 20121-10-10
Page 11 of 48
InMan DL1-Multi Single Axis Doppler Speed Log System
InMan DL1-Multi Single Axis Doppler Speed Log System
Electronics AS
Electronics AS
CHAPTER 1: HARDWARE MOUNTING
p
LaceMenT
of
The
speeD
Log
sensor
anD
BoTToM
insTaLLaTion
When placing the speed log sensor, consider the following moments:
• The DL1 doppler sensor measure speed of water in a distance 0,5-3m away from sensor.
2 acoustic signals, one pointing 30deg forward and the other pointing 30 deg aft.
• The sensor is installed into a sea valve or tank welded into the hull.
• It is necessary to select a part of the hull that is submerged and free from turbulence and
aeration under all load and speed conditions, and to avoid positions where air is trapped in
heavy weather.
The generally best placement on larger vessels is in the front region of the vessel just behind the
bulbous bow (see area A on fig ). This area is generally designed such that the bubbles are pushed
to either side of the bulb, leaving a clear area under the bulb and just behind.
• Do not mount transducers aft of bow thruster outlets, or aft of other hull installations (such
as outlets, vents or other protruding details) that may create aeration or turbulence.
• Welding seams in this area should be smoothed and rounded off in order not to create tur-
bulence or aeration and maintain a laminar waterflow at all speed ranges of the vessel.
•
Select an area that is acoustically quiet. The system operates at frequencies between 700
kHz and 740 kHz.
•
If the bottom is sloped a housing (blister) should be constructed. It is recomended to allow a
flat area of at least 30 cm in front and behind of the sensor and form the bed as a tear drop.
A
Bubbles
Sensor installation
A
Bubbles
Side view
Bottom view
Sensor placed
fore
Water relative speed is
measured at a depth between
0.3 and 3 m below transducer.
0.5
Figure showing placement of
a sensor with the individual
beams pointing fore and aft.
Figure showing the generally
best sensor placement in the
front region.
Recommended mounting area
A sea valve is highly recommended over a tank installation, as it is possible to service the sensor
(clean or replace) without docking the vessel.
The best place for sensor installation is in a dry and accessible area like bow thruster room, just in
front of the fore bow thruster, as deep as possible on the hull.
Even though sensor is approved to be installed in wet areas like ballast tank it is not recommended
If installed in a wet area special care to maintenance and maintenance access should be taken. A
dry void space is recommended. A junction box for sensor cable should be mounted close to sensor
allowing sensor change.
The sensor cable (green) is waterproof and carries digital signals to and from the sensor and power
to the
sensor. It must pass through the outer hull using a double water seal. This is included in the
bronze tube in sea valves, or in the tank and stuffing tube. The cable is 11 mm in outer diameter with
a bending radius of 25 mm.
The cable can be cut if required.
Please refer to separate manuals for bottom parts.
Manuals are available from the SKIPPER web site www.skipper.no
Retrofit Adapters
Sea Valve
SB
Sea Valve
DB
Tank
Aluminium
Tank
DL1SG-XX
Sensor for
Sea Valve
DL1ST-XX
Sensor for
Tank
DL1STA-XX
Sensor for Aluminium
Tank
