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Navico NAIS-300 Review

The Navico NAIS-300 is a full class-B marine AIS transceiver designed to display data on a compatible chartplotter, dedicated display, or on a PC with compatible software.

The NAIS-300 is housed in a waterproof plastic 5.1-inch by 8.2-inch by 2.5-inch black box (actually grey) that weighs just over 21 ounces. It is designed to mount on a flat surface either vertically or horizontally.

navico nais-300

Navico NAIS300

The unit communicates with a chartplotter display via SimNet or NEMA0183-HS. SimNet is Navico’s proprietary high speed data bus network compatible with NMEA2000. The NMEA0183-HS data transfer speed is 38,400-baud instead of the slower 4800 baud used by regular NMEA0183 units.

Bottom line here is you can only connect this AIS unit to a chartplotter capable of communicating via NMEA0183 high-speed protocol. Data transfer to a PC is via an RS-232 connector. For our testing we used both the NMEA0183-HS connection to interface the NAIS-300 with a Raymarine A50D chartplotter and the RS-232 link to connect to a Windows-based PC. Both connections functioned properly. We did not test the SimNet connection.

Four LED lights provide status information on Navico NAIS-300 functions. To put this unit in Silent mode (turning transmissions off) requires installation of a momentary on switch connected to the transponder unit.


The unit needs to 12-volt DC power supplied. Be connected to its GPS sensor, a VHF antenna for signal reception and transmission, and connect to some sort of display. Electrical connections to the Navico unit are made with provided block connectors or with a SimNet plug-in connector. We tested using the block connectors.

wiring the navico nais-300 to our test rig

Wiring the Navico NAIS300 to our test rig which used a Raymarine A50D MFD.

Installation of the Navico NAIS-300 is pretty easy. You’ll need to mount the transponder box and connect it to DC power. Then you’ll need to mount the GPS sensor and connect it to the transponder box. Lastly, you’ll need to mount and connect a VHF antenna. You’ll also need to make a data cable connection to your display of choice.

Even though the manual recommends a VHF antenna tuned specifically to the AIS frequencies we used a standard VHF radio antenna and found the unit functioned well with no issues. You should be aware when connecting this unit to a chartplotter that it will need a NMEA0183-HS port to work properly. To connect to a PC you’d use the provided RS232 (serial port) connector. If you have a newer computer that lacks a built-in serial port you’d need to get a serial to USB adapter.

Sea Trial

Our test display, the Raymarine A50D, has two NMEA0183 ports that can be manually set to 38,400-baud for high speed AIS communications. In this particular display you’ll also need to turn on the AIS data layer via a menu selection and configure the data port prior to use.

We tested the Navico NAIS-300 for functionality both on a powerboat test bed and in our lab. The output was monitored using the Raymarine A50D chartplotter display. A status icon displayed onscreen lets you know the AIS unit is connected and working properly. As per regulation, triangular shaped icons are used to display ‘sleeping targets’ onscreen, these are passing ships that are not a collision threat. We were able to display several ships simultaneously and according to the owner’s manual the NAIS-300 can handle up to 250 targets.

As ships pass outside the set safety zone they are displayed with the blue/grey triangular shaped icon of a sleeping target. Placing the cursor over a target will show the ship’s heading, speed, closet-point-of-approach (CPA), and time-closest-point-of-approach (TCPA). This data can also be selected to display at all times. A heading vector for each target can be display too. To get the full list of available AIS information on a particular target you’d hit a soft key.

Alarms and safety zone settings in the AIS1000 provide collision avoidance. You can set a safety zone around your vessel in one of four steps from a distance of a tenth of a mile up to two miles. You can also set the time of closest approach in one of four settings from three to 24 minutes. Should another vessel breach this safety zone an alarm will occur.

We checked the NAIS-300 transmitted data using the competing West Marine unit and found it transmitted data properly.

Final Thoughts

The Navico NAIS-300 worked just fine. We like the small lightweight case and the fact that it is waterproof. It carries a 2-year warranty.