Steel flanges for Doppler log

July 2011 – A Doppler log is often used to measure the speed of ships: it is a device that measures the ship’s speed in relation to the river/sea bed and/or the water. The Doppler log is mounted in steel flanges that are welded to the bottom of the forward bulwark so that the device is protected and servicing can be carried out without the vessel needing to be in dry dock. De Boer Staal supplied 60 mm grade D steel plate for these flanges. De Boer Snijbedrijf then cut the flanges to size.

In the past, a drag log was used to determine the rate of knots. This was a none-too-accurate instrument as a result of which the estimated position and the actual position were often completely different. Nowadays, the two-frequency Doppler log is in frequent use: a low ultrasonic frequency to measure ground speed where the water is deep, and a high ultrasonic frequency to measure the vessel’s speed in relation to the water speed.

The Swedish company Consilium, which has offices in Schoonhoven, is one of the largest suppliers in the world of gas and fire alarm systems, emissions monitoring systems and navigation systems. Consilium principally supplies the shipbuilding and oil/gas industries. Consilium ordered grade D steel plate from De Boer Staal, and De Boer Snijbedrijf cut the flanges in which the Doppler log is mounted to size.