Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

In recent years, equipment has improved

considerably with offerings from companies

such as Brookes & Gatehouse (B&G, http://www.

bandg.com) and Airmar (www.airmar.com).

For example, Airmar recently introduced a

new weather-monitoring sensor/transducer

that promises to change the way boaters

monitor barometric pressure, wind direction

(true and apparent), wind speed (true and

apparent), air temperature, dew point, rela-

tive humidity, and even wind chill tempera-

ture and GPS position data (see below). The

sensor is an ultrasonic device, with no mov-

ing parts. All functions are displayed on a

PC, which also can be interfaced with chart-

plotters, autopilots, and other devices. Plus

it is compatible with NMEA 0183 and

NMEA 2000 devices (see Chapter 17),

which also permits the use of conventional

instrument displays (as long as they are NMEA

compatible). They are not cheap, however,

costing around $1,000.

WeatherStation Layout

Airmar’s WeatherStation system consists of a

sensor, a power supply to the sensor, and a

converter unit that interfaces with a laptop

and is powered by the computer’s USB supply.

An optional piece of equipment called a com-

biner lets you connect to a laptop and NMEA

device simultaneously.

Installation involves the same considera-

tions as always: pay attention to sensor posi-

tioning (see below) and cable routing, and

ensure the device has a sufficient power supply.

In addition, you will need to install overcurrent

protection for the power feed conductors, based

on the manufacturer’s recommendations.

Sensor placement is critically important;

parameters are as follows:

• Proper orientation in the fore-and-aft
  plane is a must for the unit’s directional
  sensing capability to work.

162 marine electronics installation and troubleshooting

• To accurately sense airflow velocity and
  direction, it must be mounted in a location
  that ensures unobstructed and undisturbed
  airflow across the sensor surface. Airmar
  recommends a minimum of 6.5 feet (2 m)
  of clearance between the sensor and any
  obstructing object. This will not be an issue
  with sailboat installations if the sensor is at
  the top of the mast, but it could be a real
  challenge on many powerboat installations.


• Placement relative to other transmitting
  antennas is also important as they can
  disturb airflow and create turbulence
  near the sensor.


• The unit is also a GPS sensor, so interfer-
  ence from other antennas is possible (see
  Chapter 14).

The WeatherStation’s total power consump-

tion will depend on its configuration. If the

sensor is connected to a PC, then obviously the

PC will require a power supply. If NMEA-

compatible displays will be used, then each

will need its own power supply. The sensor

itself operates in the 10 VDC to 16 VDC

Typical configuration of an Airmar WeatherStation

installation.

battery

laptop

AIRMAR CONVERTER

WeatherStation