28 User’s Manual INNOMAR Parametric Sub-Bottom Profilers / SESWIN
28 Innomar Technologie GmbH (2023-01)
Pole-Mount transducer installation guidelines
Transducer depth: The upper water layers are filled with small air bubbles, especially in heavy
seas. Air bubbles absorb acoustic energy and may block entirely the desired acoustic signal.
Therefore, select a location as deep as possible for the transducers, where the water is less
aerated and you have a wider weather window. On the other hand, in shallow waters the
transducer should not be the lowest point to avoid damages by boulders etc. Also avoid sound
from HF sidelobes hitting the ship’s hull, this would produce ghost echoes.
Transducer location: Select a location as far away as possible from sources of noise. For sub-
bottom profilers, usually the ship’s engine is the dominating noise source. Prefer locations in the
forward third of the vessel, which normally will provide less aerated water, less noise and less
turbulence. At small boats the best place is at the bow. Heave will be lowest mid-ship since no
angular components are added. Avoid locations near the ship’s aft because of noise (propeller
and engine) and aerated water.
Transducer orientation: There is an arrow on top of the transducers pointing to forward direction
(ship’s bow).
Bulbous bow: If the vessel has a pronounced bulbous bow, be aware that this will transport
aerated water down. Tunnel thrusters in the bow will also produce aerated water in heavy seas.
Objects protruding from the hull: Any objects protruding from the hull as well as holes and pipe
outlets generate turbulence and flow noise. Do not place the transducer in the vicinity of such
objects, and especially not close behind them.
Mounting pole: Be aware of the need for a stiff connection between transducer and motion
sensor. Also, be aware of limitations in vessel speed as well as weather window. Avoid small
poles. Reduce vibrations and bending of the pole by proper supports and ropes. Long poles may
need a rope below the ship’s keel.
Transducer inclination: Transducers should be mounted horizontally (parallel to the water
surface) to ensure best system performance, especially for narrow- beam sub-bottom profilers
like the INNOMAR systems. A small positive inclination (bow up, max. 0.5°) is acceptable in order
to ensure laminar water flow. Avoid negative inclination since this may cause turbulences.
Electrical connection / grounding: To reduce noise caused by the mains generator the
transducer’s housing should be electrically connected to the topside unit by an additional ground
wire.
Acoustic coupling / vibration: To avoid structure-borne noise going from the ship’s hull into the
transducer, the transducer has to be decoupled acoustically by using rubber or other damping
material. The steel-to-steel connections on the flange and on the pole should be decoupled using
elastic material like rubber, plastics or wood.
Prevent corrosion: If the transducer is situated in water for a longer period of time, use zinc
anodes to prevent corrosion. Proper grounding is also essential.
Prevent bio-fouling: To reduce bio-fouling, pole-mounted transducers may be painted with an
approved water-based anti-fouling compound, see section on hull-mounted transducers below.
GNSS antenna
monitor, mouse, keyboard
motion sensor
GNSS receiver
topside unit
SBP transducer
INNOMAR “standard” installation on a small survey boat. The transducer is pole-mounted
at the bow with GNSS antenna on top. The motion sensor is also placed close to the
transducer. For system operation an external monitor is connected.
Das verkn üpfte Bild kann nich t angezeigt werden. Möglicherw eise wurde die Datei verschob en, umbenannt oder gelö scht. Stellen Sie sicher, dass die Verknüpfung auf
die korr ekte Datei und den ko rrekten Speich erort zeigt.
To Next Page
Loading...