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Sonar/Fishfinder option - Transducer Technical Specifications

Created: 06/18/2007
Modified: 06/18/2007


Frequency of Operation
The transducer designed for use with the Maptech Navigation Computer is a 170 kHz Fishfinder Sensor and a member of the Airmar family of Smart transducer sensors. It is designed to work with other installed transducers since the 170kHz is a fairly rare frequency and will not interfere with any other transducer on the vessel so long as its frequency is +/- 10 kHz from 170 kHz. For example, the most popular transducer on the market today is the split 200/50 kHz; this transducer would not interfere with the Maptech/Airmar Fishfinder Sensor as it is outside the +/- 10 kHz tolerance.

The 170 kHz Fishfinder Sensor provides real-time fishfinder, depth and temperature to the black box interface which sends the analog data to the SRN/i3 Navigator.

The 170 kHz Fishfinder Sensor's nominal power is variable up to 280 Watts RMS which is about 900 Watts peak to peak. The Maximum digital depth capability, depending on conditions, is 700 feet.

The nominal The 170 kHz Fishfinder Sensor's beam angle is 11°. The element is a 2" 170 kHz-A element.

Housing and Installation
The standard 170 kHz Fishfinder Sensor is retractable and fits into the Airmar P17 retractable transducer housing. This P17 housing is the same retractable housing used for the SRN/i3 NMEA Smart transducer. Thus, if a SRN or i3 owner wishes to upgrade to the 3D Fishfinder, swap the NMEA Smart Transducer for the 170 kHz Fishfinder Sensor without drilling another hole. In fact, the existing NMEA Smart Transducer in the hull can not be active, as it will conflict with the 170 kHz Fishfinder Sensor (as they use the same frequency.)

The optional tilt transducers are designed for situations where the transducer can not be installed on the centerline or flat spot on the hull. Depending on the hull dead rise either a 12° or 20° should be used. These transducers have the internal element tilted within the transducer so the beam points straight down while it's mounted flush on a dead rise.

Hull dead rise 0° to 6° - use the standard 0° transducer.
Hull dead rise 7° to 16° - use the 12° tilt.
Hull dead rise 16° to 28° - use the 20° tilt.
Note: When installing the 12° and 20° tilt transducers the arrow on the transducer cap should point toward the keel.

If the vessel on which the Fishfinder is to be installed on is a high speed (35+mph) boat, then the High Speed faring transducer should be used. Maptech has seen marginal results in some installations on high speed vessels.

The installation location for the transducer must be completely unobstructed:
1. The transducer must be at least 12" in front of any under water hardware.
2. No hardware can be placed in front of the transducer.
3. The transducer must be no further forward than mid ship.
4. The transducer must be in front of the propellers.
5. The transducer must be 24" away from any existing transducers.

Sonar/Fishfinder option - "Black Box" & Cable Technical Specifications
Fish Finder Extension Cables:
The 170 kHz Fishfinder Sensor uses a different extension cable then the NMEA Smart Transducer. The 170 kHz Fishfinder Sensor uses a 7 pin cable versus the 5 pin NMEA Smart Transducer. So when upgrading to a 3D Fishfinder, be sure to also change out the NMEA Smart transducer extension cable. These extension cables are available in 60' and 30' lengths.

Black Box:
The 170 kHz Fishfinder black box requires 12 volt DC power (24v power will destroy the box.) It outputs the analog Fishfinder data coming in from the 170 kHz Fishfinder transducer as well as NMEA 0183 for depth and temperature. Both NMEA depth and temperature are displayed in a data window on the Navigation Computer. The NMEA data is input on COM 4 of a Model 300 and COM 1 on a Type II. The Fishfinder analog data is input through COM 2 of a Model 300 and COM 3 on a Type II. The black box should be wired to its own on/off switch. When the black box is powered on, it runs the transducer and processes the NMEA data. Thus, regardless if power is applied to the Navigation Computer, NMEA depth and temperature data will be supplied to the NMEA bus for any other NMEA devices to display.


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