Suitable Tilt Angle - Furuno CH-37BB Operator's Manual

Case
Tilt angle
Screen
Discrimi-
nation
fish
echoes
Point to consider
• Normally, a vertically distributed schools of fish are better sonar target than the bot-
tom, because it reflect the transmitted pulse back toward the transducer.
• In case of 3, both schools of fish (a) and (b) are presented. However midwater
schools of fish tend to be larger than bottom schools of fish and they are often dis-
played near the bottom on the display.
• It is difficult to detect bottom fish when they are not distributed vertically.
2.5.3

Suitable tilt angle

The figure below illustrates the relationship among tilt angle, depth and detection
range. Refer to it to find out the suitable tilt angle for a given depth/detection range.
Tilt angle and beam coverage (frequency: 113 kHz, vertical beamwidth: 11°
20(40)
40(80)
60(120)
80(160)
100(200)
200(400)
Depth (m)
1
30° to 40°
School of fish a School of fish School of fish
B tt Bottom
School of fish is ob-
scured by the bottom
100
(200)
Vertical width of sonar beam
100m
11° 11° 11° 17m 17m 17m
2
10° to 20°
School of fish a
School of fish School of fish
Bottom
School of fish is located
above the bottom (mid-
water)
200 300
(400) (600)
300m
200m
35m 35m 35m 52m 52m 52m
2. SONAR MODE
3
0° to 5°
School of fish a School of fish a School of fish l
School of School of School of
fish fish fish
b
B tt Bottom
School of fish is located
close to the bottom
400
Range (m)
(800)
0°
5°
10°
15°
2-5