User manual NORTHSTAR EXPLORER 435

[. . . ] Explorer 435/438 Fishfinder Installation and Operation Manual www. northstarnav. com IMPORTANT SAFETY INFORMATION Please read carefully before installation and use. DANGER !It is used to alert you to potential personal injury hazards, Obey all safety messages that follow this symbol to avoidpossible injury or death. WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury CAUTION indicates a potentially hazardous situation which, if not avoided, could result in minor or moderate injury. CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not avoided, may result in property damage. [. . . ] This will produce a flat bottom trace on the screen. The appearance of the Sonar and Zoom screens can be changed to suit individual preferences. Note: Times indicated are for illustration only. 4-2 Fish detection and display Where to find fish Underwater features like reefs, wrecks and rocky outcrops attract fish. Use the sonar to find these features, then look for fish by passing over the feature slowly several times using the Zoom display (see section 5-2 Sonar Zoom display). If there is a current, the fish will often be found downstream of the feature. When fishing with the Explorer 435 and Explorer 438 with the Fish symbols Off, a weak fuzzy band may appear between the bottom trace and surface. This might indicate a thermocline - a rapid change in water temperature, such as the edge of a warm or cold current. The temperature difference can form a barrier which the fish may not swim through. In fresh water, fish often collect around a thermocline. the remaining echoes, they are displayed as either small, medium or large fish symbols - with or without depth. While the SBN processing is very sophisticated it is not foolproof - there will be times when the fishfinder will not be able to differentiate between large air bubbles, rubbish containing air, fishing floats etc. The following picture shows the Sonar display with the Fish symbol: On + depth: Fish symbols The fish symbol can be customized or switched off altogether so that the echoes are not converted to fish symbols on the display. The differences between Fish symbol On and Off are: Fish symbol Off For experienced users this always provides the best information as every echo is displayed, whether it is surface clutter, a thermocline or a fish. The picture in section 4-1 Interpreting the display, shows the Sonar display with the Fish symbols Off. The fish appear as arches. 19 Fish symbols On Using Northstar's SBN sonar technology the fishfinder analyses all echoes and eliminates most false signals and clutter so that remaining targets are most likely fish. Depending on the strength of Northstar Explorer 435/438 Installation and Operation Manual Fish arches In good conditions and with Fish symbols Off, a fish passing through the cone-shaped ultrasonic pulse is displayed as a fish arch. A fish arch occurs when a fish enters the weak edge of the sonar cone, generating a weak echo that is displayed as the first pixel of the fish arch. As the fish moves closer to the middle of the cone, the distance between the transducer and the fish reduces and the echo is displayed at progressively shallower depths, producing the start of an arch. When the fish passes directly beneath the middle of the cone, the echo becomes strongest and thickest. As the fish passes out of the middle of the cone the reverse happens with a progressively weaker and deeper echo. There are many reasons why fish arches may not be seen. For example: · · Transducers Installation Guide). [. . . ] Try installing a one-way valve between the fuel transducer and the fuel tank. c) The Set remaining fuel value must be reset after every refuelling (see section 3-3 Setup > Fuel). d) The fuel tank may not refill to the same capacity each time due to air pockets. This is particularly noticable with underfloor tanks. [. . . ]