NorthStar Navigation 438 Using the Explorer 435 and Explorer, Interpreting the display

Temperature

The factory settings should be sufficiently accurate for normal usage. To calibrate the temperature readout, first measure the water temperature with a thermometer known to be accurate.

Use the cursor keys to display the temperature readout box, then increase or decrease the value to match the measured temperature. The temperature can be set from 32° to 99.9°F (0° to 37.7°C) with a resolution of 0.1° unit.

To change the units between °F (Fahrenheit) or °C (Celsius), see section 3-7 Setup > Units.

Fuel

Calibrating the fuel usage can improve the accuracy of fuel measurements.

Twin engine installations require each fuel transducer to be calibrated. This can be done at the same time with two portable tanks or at different times using one portable tank.

Calibrating the fuel transducer(s) requires accurate measurement of the fuel consumption. This is best done using a small portable tank. At least 4 gallons (15 litres) of fuel should be used to ensure an accurate calibration.

It is often very difficult to fill underfloor tanks to the same level twice due to air pockets, so the more fuel used, the more accurate the calibration.

To calibrate the fuel transducer(s), perform the following steps:

1.Record the level of the fuel in the tank(s).

2.Connect the portable tank(s) to the engine through the fuel transducer(s).

3.Run the engine at normal cruising speed until at least 4 gallons (15 litres) of fuel has been used per engine.

4.Check the actual amount of fuel used per engine by refilling the portable tank(s) to the original level and noting the reading(s) from the fuel dispenser’s gauge.

5.Select Fuel. Use or to change the reading to match that on the fuel dispenser’s gauge.

6.Press when the reading is correct.

Note: If the fuel calibration options appear to give erroneous readings after a while, first check that the fuel sensor has been installed correctly according to the installation instructions supplied with it, then see Appendix B - Troubleshooting.

Keel Offset

Keel offset is a depth correction representing the vertical distance between the depth transducer and the location from which the depth is to be measured.

Enter a positive keel offset value when the transducer is located below the water surface but the total depth is required.

Enter a negative keel offset value when the depth below the deepest part of the boat is required (such as the keel, the rudder or the propeller) and the transducer is located closer to the water surface.

Use the cursor keys to select Keel offset, then press to display the Keel offset box.

Use the or cursor keys to adjust the value.

Water surface

Positive

	Depth of transducer		value
		Negative
Transducer
			value
Note: Boat illustrated uses a through hull transducer

4 Using the Explorer 435 and Explorer 438

This section explains how to interpret the sonar displays and how fish are detected and displayed. It also describes Gain and Range and shows

examples of some of the different sonar displays. Also see section 1-2 How the Explorer 435 and Explorer 438 works.

4-1 Interpreting the display

The sonar displays do not show a fixed distance travelled by the boat; rather, they display a history, showing what has passed below the boat during a certain period of time.

The history of the sonar signal displayed depends

the depth of the water and the scroll speed setting.

In shallow water, the echoes have a short distance to travel between the bottom and the boat. In deep water, the history moves across the display

16 Northstar Explorer 435/438 Installation and Operation Manual