Raymarine Marine GPS System User Manual download pdf (Page 125)

RayTech Navigator User’s Guide

5-34

Fish Indications

When the Fishfinder detects a fish, it displays an arch-shaped mark.

In general, a larger arch indicates a larger fish, though this is not

always true. For example, if there are two fish of the same size:

one is close to the surface, the other is near the bottom. The fish that

is close to the surface has a larger arch because, being closer, more

sound waves are returned to the Fishfinder.

The sound waves are actually reflected by an air sac near the center of

the fish, not by the body of the fish. The size of this air sac is different

for different kinds of fish and this can affect the size of fish arches on

the image. A fish with a large air sac produces a large fish arch, while a

fish with a small sac produces a small arch. Several arches together

show a school of fish. Figure 5-11 shows some example target images.

To display the depth of the fish:

1. Click MENU on the Pathfinder Panel

2. Click TARGET DEPTH ID.

Figure 5-11. Sonar Target Image Key

1 ... 124 125 126 ... 188

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Raymarine Marine GPS System User Manual Page 125