Furuno DS-60 Operator's Manual page 9

Remarks on usage of the DS-60
The DS-60 measures ship's speed by detecting the Doppler shift frequency of the echo reflected
by a watermass (water layer containing plankton and other micro-organisms) located within the
measuring area, which is usually about 2 m. In some instances, however, no signal is returned
because of too few plankton in the sensing depths. This phenomenon can occur in particular areas
in particular seasons. The probable cause is the plankton are lying in deep water because an
ice-melted cold water mass covers the sea surface. Similar cases may also occur in a freshwater
lake. Under these circumstances the DS-60 will not show the correct ship's speed.
Conditions which may affect accuracy (with ref. to IMO A.824/3.3)
The Doppler speed log DS-60 is designed for reliable and accurate performance through
FURUNO's long experience and advanced technology. It operates on the best choice of system
frequency and power output.
As far as the sonic energy is used, the performance (accuracy) may be reduced or even lost
under:
• rough weather (may be sea state 6 or severer)
• improper location of sensor (e.g., too close to the propeller, thrusters, drain tubes, echo sounder
equipment)
• depth under the keel, if less than 3m
The accuracy will not be affected by:
• water temperature (sound velocity)
• salinity
• pitch/roll ±10°
Beware of transducer location
The transducer may be damaged if it hits the dry dock blocks. Take the following measures to
prevent damage to the transducer.
1. Before delivering the ship, draw up a suitable docking plan taking into account the dimensions
and location of the transducer. Store the plans onboard the ship.
2. Place the dry dock blocks according to the plan.
3. Have a diver check the position between the transducer and the blocks before removing the
water. Confirm that the transducer will not touch the blocks.
CE/UKCA declaration
With regards to CE/UKCA declarations, please refer to our website (www.furuno.com) for further
information about RoHS conformity declarations.
Disclosure of Information about China RoHS
With regards to China RoHS information for our products, please refer to our website
(www.furuno.com).
FOREWORD
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