Speed measurement. The speed measurement is picked up from an NK impeller, as used with their Speedcoach range of products. The PowerLine sensor is very sensitive, ensuring that alignment between impeller and sensor need not be too precise. Correct operation up to 60mm is assured - we have measured correct operation up to 200mm in some installations!
Whilst an impeller provides excellent repeatability in speed and distance measurement, its location on the hull, specifically its distance from the bow, will affect its absolute calibration. The system therefore enables a scaling factor to be entered to correct for this. The routine for determining the scaling factor should involve traversing a course of known length, and comparing this to the distance recorded by the system. The ratio of the two gives the scaling factor.
Acceleration measurement. A high grade accelerometer is contained within the package to provide a precise measure of hull check and pickup. For correct operation, the sensor must be aligned fore/aft in the boat, with the cable pointing towards the stern. Since we only want to measure horizontal acceleration, it would normally be important to mount such a sensor with precise horizontal alignment. However, we realised how difficult that is in a boat, so we have eliminated the need for that! - the sensor is able to work out its alignment and automatically adjusts to read only the horizontal component of acceleration.
Quality manufacture. As with all sensors in the PowerLine range, only high grade materials are used in its construction. The housing is a lightweight anodised aluminium, totally corrosion-proof. The size of the sensor is 40mm(l)x20mm(w)x16mm(h).