User manual RAYMARINE L750 FISHFINDER

[. . . ] Distributed by Any reference to Raytheon or RTN in this manual should be interpreted as Raymarine. The names Raytheon and RTN are owned by the Raytheon Company. L750 Fishfinder Operation Handbook Raymarine Contents i Contents Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 About the L750 Fishfinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] A shallow arch is generated when the boat is moving slowly. This shows a fish detected in sidelooker mode. A fish moving under a stopped boat shows as a line. When the boat is moving very fast, a fish appears as two parallel lines. Fig. 3-4 Fish Indications 38 L750 Fishfinder: Installation and Operation Handbook the surface will have a larger arch. This is because the fish which is closer returns more of the sound waves back to the Fishfinder. Actually, the sound waves are usually reflected by the air sac near the center of the fish, and not by the body of the fish. The size of this air sac is different for different kinds of fish. This can also affect the size of the fish arches on the display. A fish with a large air sac will produce a large fish arch, while a fish with a small sac will produce a small arch. Several arches together show a school of fish. The return from a fish will have a different appearance, depending on the frequency used. If a fish is spotted by the wide 50 kHZ beam, the arch will be broad. When using the narrower 200 kHz beam, the same fish will produce a narrower arch. The shape of the arch is also affected by the speed of the boat. If the boat is moving slowly, the arches tend to be longer. If the boat is moving more quickly, the arches are short and peaked. If the boat is moving very fast, a fish may be indicated by a single vertical line. When the Fish Symbol feature is turned on a fish will be indicated by a fish-shaped symbol on the display. In general, a larger symbol means a larger fish. The symbol also indicates which of the two frequencies was used to locate the fish. If the fish was spotted by the wide 50 kHz beam, the symbol will appear to be hollow. If the fish was detected by the narrow 200 kHz beam, the symbol will be solid. Bottom Indications The bottom usually produces a strong echo, so it is easy for the Fishfinder to see a lot of detail. The Fishfinder can indicate many different kinds of bottom conditions. [. . . ] The rear-most part of the boat's hull, often a flat panel. A feature used to help display fish near the bottom. This feature helps to show the difference between weak returns (including fish near the bottom) and strong returns (including the bottom itself). A way of magnifying or enlarging part of the display to give a better view of a section of the water. Zoom: Limited Warranty Certificate Raymarine warrants each new Light Marine/Dealer Distributor Product to be of good materials and workmanship, and will repair or exchange any parts proven to be defective in material and workmanship under normal use for a period of 2 years/24 months from date of sale to end user, except as provided below. [. . . ]