Koden KDS-6000BB User manual

Declaration of Conformity
(As referred to in Annex IV 2. of Directive 2004/108/EC)
Declares under his sole responsibility that the produced Digital Broadband Sonar manufactured by
Koden Electronics Co., Ltd.
5278 Uenohara
Uenohara-Shi,
Yamanashi-Ken
409-0112, Japan
Telephone [phone] Telefax [phone]
Identified by the type number KDS-6000BB to which this declaration refers conforms to
the relevant essential requirements of Directive 2004/108/EC and is in conformity with the EMC
requirements of EU harmonised standard
EN60945: 2002
Authorised representative in Europe
Heinz Hoghoff
Koden Elektronik GmbH.
Am Gewerbepark 15
D-64823, Gross–Umstadt
Germany.
Phone [phone]
Telefax+49 6078 73824
Signed
Heinz Hoghoff,
Dated 28 Aug, 2014
Document No. 74-2731U-X001

KDS-6000BB Revision History
0093160002-05 i
KDS-6000BB Operation Manual
Doc No: 0093160002
Document Revision History
No. Doc. No.- Rev. No. Revised Date
(Y/M/D)
Revised Content
0 0093160002-00 2014/09/30 First edition
1 0093160002-01 2014/12/05 System Configuration, Configuration of Equipment
2 0093160002-02 2015/05/11 Revision (From software KM-F35 Ver01.06 to Ver01.**)
3 0093160002-03 2015/11/10 Configuration of Equipment
4 0093160002-04 2016/02/22 Revision (From software KM-F35 Ver01.09 to Ver01.**)
Configuration of Equipment, Chapter 4
5 0093160002-05 2016/05/20 Revision (From software KM-F35 Ver01.10 to Ver01.**)
6
7
8
9
10
Document No. Revised Version Norm
When part of the document needs to be revised, the document has advanced revision number.
The document No. is indicated at the lower right side on the cover and at the left or right side of the
footer region of each page.
© 2014-2016 Koden Electronics Co., Ltd. All rights reserved.
No part of this publication may be reproduced, transmitted, translated in any form by any means
without the written permission of Koden Electronics Co., Ltd. The technical descriptions contained in
this publication are subject to change without notice. Koden assumes no responsibility for any errors,
incidentals or consequential damages caused by misinterpretation of the descriptions contained in this
publication.

Important Notice KDS-6000BB
ii 0093160002-05
Important Notice
• For copy and transcription of this Operation Manual (hereinafter referred to as this manual),
permission from Koden is needed. Koden prohibits the un-authorized copy and
transcription of this manual.
• If this manual is lost or damaged, consult a dealer of Koden or Koden.
• The specification of the products and the contents in this manual are subject to change
without notice.
• The contents displayed on the menu of product may be different from the expression of
this manual. The fonts and shapes of the keys and menus in the illustration may differ from
the actual ones, and some parts may be omitted.
• Koden is not liable for damages and troubles arisen from misunderstanding of the contents
in this manual.
• Koden is not liable for any damages caused by earthquake, lightning, wind and flood
damage and fire for which Koden is not responsible, and actions by third parties, other
accidents, customer’s unintended error/abuse and the use under other abnormal
conditions.
• Koden is not liable for damages of accompaniment (change/loss of memorized content,
loss of business profit, stop of business) arisen from use or failure of our products.
• If the stored data are changed or lost, irrespective of causes of troubles and damages,
Koden is not liable for them.
• Koden is not liable for any damages arisen from malfunction caused by combination of
software and connected equipment in which Koden is not engaged.

KDS-6000BB For Your Safe Operation
0093160002-05 iii
For Your Safe Operation
Symbol used in this Operation Manual
The following pictograms are used in this manual. The meaning of each symbols shall be well
understood and the maintenance and inspection shall be carried out.
Symbol Meaning
Mark for warning
This mark denotes that there is a risk of death or serious injury when dealt
with incorrectly.
Mark for danger of high voltage
This mark denotes that there is a risk of death or serious injury due to
electric shock when dealt with incorrectly.
Mark for caution
This mark denotes that there is a risk of slight injury or damages of
devices when dealt with incorrectly.
Mark for prohibition
This mark denotes prohibition of specified conducts. Description of the
prohibition is displayed near the mark.
Caution items on equipment
Be careful of high voltage inside
High voltage, which may risk your life, is used. This high voltage may
remain in the circuit even after the power is switched off. To prevent
contact with the high voltage circuits accidentally, a protective cover or
the label with this mark is provided on the high voltage circuit. When the
inside is to be checked, ensure to switch off the power and to discharge
the residual voltage for safety. An engineer authorized by Koden shall
carry out the inspection and maintenance works.
Power off in the boat
An accidental power-on during works may result in worker’s
electrification. To prevent such accident in advance, ensure that power
in the boat and on the equipment are switched off. Furthermore, it is
safer to hang a caution tag saying “Under work” near the power switch
of equipment.
Be careful of dust
Inhaled dust may cause respiratory affection. At the time of cleaning the
inside of equipment, be careful not to inhale dust. Wearing a safety
mask is recommended.
Warning
Warning
Caution
Warning

For Your Safe Operation KDS-6000BB
iv 0093160002-05
Caution on location of installment
The equipment shall not be installed at locations which are excessively
damp and suffers from water drops. Otherwise, dew condensation may
occur inside the display screen, and corrosion may occur inside the unit
box.
Measures against static electricity
Static electricity may be generated from the carpet on the floor in the
cabin or clothes made of synthetic fiber, and it may destroy the
electronic components on circuit boards. The circuit boards shall be
handled with appropriate measures against static electricity.
Caution at installation of Transducer unit
Transducer unit shall be installed at locations where there is no effect by
bubble and noise. Bubble and noise may seriously degrade the
performance of this equipment.
Cautions on handling
No disassembly or modification of this equipment is allowed. It may lead
to failure, firing, smoking or electric shock. In case of failure, please
contact Koden’s dealers or Koden.
In case of smoking or firing, switch off the power in the boat and of this
equipment. It may lead to firing, electric shock or damages.
Be careful of residual high voltage
High voltage may remain in capacitors for several minutes after
switching off the power. Before inspection of the inside, please wait at
least 5 minutes after switching off or discharge the residual electricity in
an appropriate manner. Then, start the work.
The information displayed on this equipment is not intended to use for
your navigation. For your navigation, be sure to see the specified
materials.
Please use the specified fuses. If un-specified fuses are used, they may
cause firing, smoking or damages.
Be sure to submerge the Transducer unit in water before transmission.
If not, it may be damaged.
Caution
Caution
Caution
Warning
Warning
Caution
Caution
Caution

KDS-6000BB Contents
0093160002-05 v
Contents
Document Revision History .....................................................................................................i
Important Notice ..................................................................................................................... ii
For Your Safe Operation........................................................................................................ iii
Contents .................................................................................................................................v
Introduction.......................................................................................................................... viii
System Configuration ............................................................................................................ ix
Configuration of Equipment....................................................................................................x
Basic knowledge for making use of sonar........................................................................... xvi
Chapter 1 Preparation.............................................................................................1-1
1.1 To use keys............................................................................................................. 1-1
1.2 Power On/Off .......................................................................................................... 1-4
1.2.1 Power On ......................................................................................................................... 1-4
1.2.2 Power Off ......................................................................................................................... 1-5
1.2.3 Power Voltage Alarm........................................................................................................ 1-5
1.3 Selection of language to be displayed .................................................................... 1-5
1.4 To use Menu ........................................................................................................... 1-6
1.4.1 Open/Close the Menu...................................................................................................... 1-6
1.4.2 Operation of the Menu ..................................................................................................... 1-6
1.5 Adjustment of brilliance........................................................................................... 1-8
1.5.1 Adjustment of LCD brilliance ........................................................................................... 1-8
1.5.2 Adjustment of panel brilliance ............................................................................................. 1-8
1.6 Screen display ........................................................................................................ 1-9
1.6.1 Sonar mode display ....................................................................................................... 1-10
1.6.2 Sonar mode Operation ...................................................................................................1-11
1.6.3 Bottom-scan mode display ............................................................................................ 1-13
1.6.4 Bottom-scan mode operation......................................................................................... 1-14
1.6.5 Echo sounder mode display .......................................................................................... 1-15
1.6.6 Echo sounder mode operation....................................................................................... 1-16
1.6.7 Sonar & One line mode display ..................................................................................... 1-17
1.6.8 Sonar & One line mode operation ................................................................................. 1-18
1.6.9 Sonar x 2 mode display ................................................................................................. 1-19
1.6.10 Sonar x 2 mode operation ............................................................................................. 1-20
Chapter 2 Function setting ......................................................................................2-1
2.1 Menu configuration ................................................................................................. 2-1
2.1.1 Initial setting ..................................................................................................................... 2-1
2.2 Menu1..................................................................................................................... 2-4
2.2.1 Frequency, Frequency 2................................................................................................ 2-5
2.2.2 Range (Sonar, Off-center) (Bottom-scan) (Echo sounder) .............................................. 2-5
2.2.3 GAIN (TD) ........................................................................................................................ 2-6
2.2.4 Dynamic range................................................................................................................. 2-7
2.2.5 Pulse width....................................................................................................................... 2-8
2.2.6 TX power.......................................................................................................................... 2-9

Contents KDS-6000BB
vi 0093160002-05
2.2.7 FIR (Bandwidth) ............................................................................................................. 2-10
2.2.8 Interference rejection ..................................................................................................... 2-12
2.2.9 Noise reduction ..............................................................................................................2-12
2.2.10 Image correction ............................................................................................................ 2-13
2.2.11 Color selection ...............................................................................................................2-14
2.2.12 Background color ........................................................................................................... 2-14
2.2.13 Color palette................................................................................................................... 2-15
2.2.14 Initialization of Color palette ........................................................................................... 2-18
2.2.15 Color rejection ................................................................................................................ 2-19
2.2.16 Sub-screen selection...................................................................................................... 2-20
2.2.17 Sub-screen display......................................................................................................... 2-22
2.2.18 Wake range (Sub-screen) .............................................................................................. 2-22
2.2.19 Language ....................................................................................................................... 2-24
2.3 Menu2 ................................................................................................................... 2-25
2.3.1 Step (Sonar, Off-center) ................................................................................................. 2-26
2.3.2 Step (Bottom-scan) ........................................................................................................ 2-27
2.3.3 Off-center position.......................................................................................................... 2-28
2.3.4 A scope........................................................................................................................... 2-29
2.3.5 White line........................................................................................................................ 2-29
2.3.6 Scale .............................................................................................................................. 2-30
2.3.7 Internal buzzer volume................................................................................................... 2-31
2.3.8 NMEA monitor ................................................................................................................ 2-32
2.3.9 Compass display ............................................................................................................ 2-33
2.3.10 Bearing display...............................................................................................................2-33
2.3.11 Wake display .................................................................................................................. 2-34
2.3.12 Wake memory interval.................................................................................................... 2-35
2.3.13 Sonic speed ................................................................................................................... 2-36
2.3.14 True / Relative bearing ................................................................................................... 2-37
2.3.15 Target lock...................................................................................................................... 2-37
2.3.16 Ext synchronized ............................................................................................................ 2-39
2.3.17 Depth unit....................................................................................................................... 2-40
2.3.18 Temperature unit ............................................................................................................ 2-40
2.3.19 Temperature adjustment ................................................................................................ 2-41
2.3.20 Range & Speed unit ....................................................................................................... 2-42
2.3.21 Train correct ................................................................................................................... 2-43
2.3.22 Power freq adjust ........................................................................................................... 2-44
2.3.23 Step (Bearing center) ..................................................................................................... 2-44
2.3.24 Audio level...................................................................................................................... 2-45
2.3.25 Audio tune ...................................................................................................................... 2-46
2.3.26 One line display..............................................................................................................2-47
2.3.27 One line scale ................................................................................................................2-48
2.3.28 One line shift .................................................................................................................. 2-49
2.3.29 One line interval .............................................................................................................2-50
2.4 Menu3 ................................................................................................................... 2-51
2.4.1 Baud rate........................................................................................................................ 2-52
2.4.2 Selection of NMEA output .............................................................................................. 2-52
2.4.3 Simulation....................................................................................................................... 2-53

KDS-6000BB Contents
0093160002-05 vii
2.4.4 Menu time-out period..................................................................................................... 2-54
2.4.5 Hull unit auto up ............................................................................................................. 2-54
2.4.6 Hull unit operation at the start........................................................................................ 2-55
2.4.7 Transducer unit baud rate.............................................................................................. 2-56
2.4.8 Slow down the Bearing speed ....................................................................................... 2-57
2.4.9 Menu (transparent) ........................................................................................................ 2-57
2.4.10 Message (transparent)................................................................................................... 2-58
2.4.11 Sub-screen (transparent)............................................................................................... 2-59
2.4.12 Information display......................................................................................................... 2-59
2.4.13 Localtime offset.............................................................................................................. 2-60
2.4.14 Dynamic range standard................................................................................................ 2-61
2.4.15 The origin detection ....................................................................................................... 2-63
2.5 [CM] keys.............................................................................................................. 2-64
2.5.1 Initial setting of [CM] keys.............................................................................................. 2-64
2.5.2 Function of [CM] keys .................................................................................................... 2-67
2.5.3 Store in [CM] keys.......................................................................................................... 2-67
2.5.4 Store a new setting in another [CM] key based on a particular setting in a [CM] key ... 2-67
2.6 Function keys ([F] keys)........................................................................................ 2-69
2.6.1 Setting to function to [F] keys ........................................................................................ 2-69
2.6.2 Assign intended operation to function keys ................................................................... 2-69
2.6.3 Event (TLL) .................................................................................................................... 2-70
2.7 Remote control set................................................................................................ 2-71
2.8 Maintenance ......................................................................................................... 2-71
Chapter 3 Operation keys .......................................................................................3-1
3.1 To use keys............................................................................................................. 3-1
3.1.1 Presentation mode key .................................................................................................... 3-1
3.1.2 Range key........................................................................................................................ 3-1
3.1.3 Sector key ........................................................................................................................ 3-2
3.1.4 Gain key........................................................................................................................... 3-2
3.1.5 TVG key ........................................................................................................................... 3-3
3.1.6 Power/Panel brightness key ............................................................................................ 3-8
3.1.7 Hoist/Lower key ............................................................................................................... 3-8
3.1.8 Bearing center key........................................................................................................... 3-9
3.1.9 Tilt key............................................................................................................................ 3-10
3.1.10 VRM key .........................................................................................................................3-11
3.1.11 Target lock key ............................................................................................................... 3-17
3.2 Remote controller (RCW-14) (Optional)................................................................ 3-18
3.2.1 Remote key set .............................................................................................................. 3-18
Chapter 4 Appendix ................................................................................................4-1
4.1 External view and dimensions ................................................................................ 4-1
4.2 Disposal .................................................................................................................. 4-5
Chapter 5 Index.......................................................................................................5-1

Introduction KDS-6000BB
viii 0093160002-05
Introduction
KDS-6000BB is digital broadband sonar with broadband Transducer units.
This unit equipped with the latest digital process can accurately display circumstances in the
water under all conditions.
KDS-6000BB is the Black Box type without the display unit, for which customer can select the
display monitor of preference. The external monitor and connecting cable are user supply.
The signal to an external monitor is analog VGA.
Koden has 17 inches LCD monitor as option.
The main features of this unit are as follows:
・This unit is a digital broadband sonar with broadband Transducer units. It can be set in a
range of 130 to 210 kHz.
・With a simple operation on a menu, frequencies can be optionally set within a wide range.
・The operation units can be easily installed from the front side by flush mounting.
・VGA analog output to an external monitor unit is provided as standard. The use of external
monitor enables to observe the sonar images from the place distant from the main unit
(External monitor is owner supply).
・The data for image, waypoint and setting data can be backed up to the USB memory, to be
recalled.
・As the operation unit is separated, operation away from the processor unit is possible.
・In Sona-ToneTM model, Sonar sound function provides fish school status by sound.

KDS-6000BB System Configuration
0093160002-05 ix
System Configuration
Connection Diagram
Onboard DC
power supply
10.8 to
31.2VDC
J8 (6P)
Remote controller
RCW-14
Display unit
17 inch LCD monitor
is acceptable
Echo sounder
GPS Compass
NMEA Converter
TD shaft
ESR-1504(1411mm)
/ESR-160 32679C-2(1681mm)
/ESR-160 32679C-3(1981mm)
/ESR-160 (40φ-4t-3000mm)
Shaft guide
ESR-1510
ESR-1511
For ESR-1507
Hull unit
DHU-630
TD tank
ESR-1506
/30927C-2
/30927C-3
/ESR-1507
/FRP TD tank set
_G16ELA0010
Gum packing
ESR-1512
Transducer unit
DHU-6302
with 10m cable
Onboard AC
power supply
100/115VAC
200/230VAC
AC power cable
VV-2D 8-3M
CW-373-5M
CW-376-5M
POWER (3P)
J6 (8P) J2 (12P)
J1 (5P)
CW-259-2M
Hull unit
control cable
CW-593-20M
TD position
alarm / Ext.
Sync. Box
JB-36
DOU-620
DOU-620R
(with RCW-14)
CW-576-0.5M
J5 (10P)
External monitor
D-sub15P
Cable for external
monitor
(CW-560-2M is
acceptable)
CW-275-10M
Transducer unit
extension cable
CW-590-15M
18P female
18P male
Processor unit
DPU-610
DPU-610ST
(Sona-Tone
TM
model)
J7 (16P)
15P
Onboard DC
power supply
10.8 to
31.2VDC
Trigger In/Out
CW-413-5M
CW-412-5M
Hull unit
DHU-6301
Power rectifier
PS-010
Operation
unit
External speaker
NP-108
DPU-610ST
(Sona-Tone
TM
model)
Cable for
external speaker
Standard
Option
Owner supply
Legend

Configuration of Equipment KDS-6000BB
x 0093160002-05
Configuration of Equipment
Standard Equipment Configuration List
a. DPU-610/610ST (Processor unit), DOU-620/620R (Operation unit)
No Name of item Type Remark Weight/
Length Qty
1 Processor unit
DPU-610/
DPU-610ST
(Sona-ToneTM
model)
No display unit
VGA output
5.1kg 1
2-1 Operation unit
DOU-620 With mounting bracket
and 5m cable
1.1kg 1
2-2 Operation unit
DOU-620R With mounting bracket,
5m cable and Remote
controller (RCW-14
with 5m cable)
DOU-620
1.1kg/
RCW-14
0.31kg
3 TD position alarm / Ext.
Sync. Box
JB-36 With 5m cable
(CW-413-5M/With 5 pin
connector and one end
plain)
5m 1
4 DC power cable
CW-259-2M
With 3 pin connector
and one end plain
2m 1
5 Transducer unit extension
cable
CW-590-15M With a 18 pin connector
and a 12 pin water
resistant connector
15m 1
6 Audio system plug
MP-105LC-RoHS For Sona-ToneTM
model
1

KDS-6000BB Configuration of Equipment
0093160002-05 xi
b. TD tank / TD shaft
No Name of item Type Remark Weight/Lengt
h Qty
7 Fuse F-7161-10A/N30C-125V
Cylinder (ø 6.4x30)
Normal fusion type
for main power
3
8 Operation manual KDS-6000BB.OM.E English 1
9 Quick Reference KDS-6000BB.QR.E English 1
10 Installation manual KDS-6000BB.IM.E English 1
No Name of item Type Remark Weight/Length Qty
1 TD tank
ESR-1506 (PVC) 1230mm
30927C-2 (PVC) 1500mm
30927C-3 (PVC) 1800mm
ESR-1507 (FRP) 1500mm
Select according to
equipment.
*Refer to Option
list.
9.0kg
11.0kg
13.0kg
12.0kg
1
2 TD shaft
ESR-1504
ESR-160_32679C-2
ESR-160_32679C-3
ESR-160_40φ-4t-3000mm
Select according to
equipment.
*Refer to Option
list.
1411mm
1681mm
1981mm
3000mm
1
Caution: TD tank and TD shaft are options.

Configuration of Equipment KDS-6000BB
xii 0093160002-05
×８
×８
×８ ×８
c. DHU-6301 (Hull unit)
Package 1-1
No Name of item Type Remark Weight/Length Qty
1 Hull unit
DHU-6301 17.0kg 1
2 DC power cable CW-275-10M Cable is built
into the Hull
unit
10m 1
3 Hull unit
control cable
CW-593-20M Cable is built
into the Hull
unit
20m 1
c. DHU-6302 (Transducer unit)
Package 2-1
No Name of item Type Remark Weight/Length Qty
1 Shaft guide ESR-1510 3
2 Bolt set SUS-M16-55-Assy
(M16x55L, 2W16U,
SW16U, N16U)
EACH
8
3
Gum packing for flange ESR-1512 Gum 1

KDS-6000BB Configuration of Equipment
0093160002-05 xiii
No Name of item Type Remark Weight/Length Qty
4 Crank handle OB-03 1
Grease 100g 1
Fuse
F-7161-4A
F-7161-8A
At input of 12 V
At input of 24 V
EACH
3
ANP base ANP-1 2
Binding Band AB-100-1000 2
5 Damper 34924D 1
Fixing collar 32681D 2
Shaft cap 34378D 1
Cap bolt CB4Ｘ10U 4
HEX rod wrench 1.5mm ×１
2.5mm ×1
3.0mm ×1
EACH
1
1 SET
4A
8A

Configuration of Equipment KDS-6000BB
xiv 0093160002-05
Package 2-2
Caution: Don’t carry the Transducer unit (DHU-6302) by holding its cable. Such
manner may cause breakage of the equipment.
No Name of item Type Remark Weight/Length Qty
1 Transducer unit DHU-6302 With 10m cable
(With 18 pin
water resistant
connector)
9.0kg 1
2 Bath cork Bath cork (White) 50g 50g 1
HEX rod wrench 3.0mm ×1
5.0mm ×1
EACH
1

KDS-6000BB Configuration of Equipment
0093160002-05 xv
Option List
No Name of item Type Remark
1 Remote controller RCW-14 With 5m cable, (Assembled the
connection cable into the Operation unit)
2
TD tank
(For *xxxx mm of TD
shaft)
*TD shaft length
ESR-1506 PVC, 1230mm (For 1411mm of TD shaft)
30927C-2 PVC, 1500mm (For 1681mm of TD shaft)
30927C-3 PVC, 1800mm (For 1981mm of TD shaft)
ESR-1507 FRP, 1500mm
FRP TD tank set
(Including Shaft guide)
ESR-1507(1), ESR-1510(2),
ESR-1511(2)
3 Shaft guide ESR-1510 ESR-1506 / 1507
ESR-1511 ESR-1507 (For FRP TD tank)
4 Power rectifier PS-010 With 2 pieces of 5A fuse
5 AC power cable VV-2D8-3M Both ends plain
6 Connecting cable CW-372-5M 5m With 5 pin water resistant connector and
one end plain
CW-373-5M 5m 6 pin water resistant connectors at both
ends
CW-376-5M 5m With 6 pin water resistant connector and
one end plain
Cable for external monitor CW-576-0.5M 0.5m With 10 pin water resistant connector and
D-Sub connector
CW-560-2M 2m D-Sub 15 pin connectors at both ends
7 Junction box JB-35 1 input, 3 outputs with CW-376-5M
8 TD shaft ESR-1504 1411mm
32679C-2 ESR-160_1681mm
32679C-3 ESR-160_1981mm
40φ-4t-3000mm ESR-160_3000mm
9 Monitor 17inch LCD Monitor With power cable and signal cable
10 External speaker NP-108 With 5m cable
(For Sona-ToneTM model)

Basic knowledge for making use of sonar KDS-6000BB
xvi 0093160002-05
Basic knowledge for making use of sonar
We suppose that you, the user of sonar, already know how to use sonar. In this section we
will theorize your experience to improve your fishing.
1. Propagation of ultrasonic wave
(1) Propagation speed of ultrasonic wave
The propagation speed of ultrasonic waves in the sea water is said to be about 1,500m per
second.
However it differs very much depending on the seasons and sea areas during a year.
The cause of the difference depends on the following 3 factors:
• Sea water temperature (°C)
• Salt concentration (%)
• Water pressure (water depth) (m)
Consequently, when thinking of the propagation speed at the surface layer zone, the speed
differs according to the sea area and also, even in the same sea area, it becomes different on
account of vertical propagation.
As a result of surveys conducted at various sea areas in the world, it has been made clear
that the difference between maximum and minimum speeds is as much as 100 (m/sec). In a
sea area having a fixed salt concentration, the propagation speed of ultrasonic wave
increases on an average by the following:
• About 3m/sec every time sea water temperature rises 1°C
• About 1.7m/sec every time water depth increases 100M
(about 10 atmospheric pressure)
(2) Absorption and attenuation of ultrasonic wave
When an ultrasonic wave is emitted into the sea water, the energy attenuates progressively
as the distance becomes farther. It indicates that the higher the frequency becomes, the
greater the absorption and attenuation of ultrasonic wave become. The main causes are;
• Attenuation of ultrasonic wave caused by the decrease of the acoustic energy density
due to the reflection, refraction and dispersion in water.
• Attenuation of ultrasonic wave caused by the conversation from the acoustic energy to
other energy due to absorption by the viscosity of medium.
(3) Influence by marine conditions
The sea water temperature changes according to the three layers which are roughly classified into
the surface, middle and lower layers.
Sea surface
Sea bottom
Atmosphre
Surface layer
Middle layer
Lower layer