Speaker
Description
Underwater noise emission of vessels is usually declared by radiated noise level (LRN). LRN must be tested in Finnish seas using a method which is suitable for shallow water (30150 m). There is not much public data about the LRNs of vessels sailing in Finnish seas nor vessels built in Finnish shipyards. Knowledge of LRN of current vessels is needed in maritime industry since IMO has encouraged all member countries to reduce LRN in the future. Our purpose was to describe the method which was recently applied in Finland to collect LRN data, and to demonstrate the data obtained so far. All measurements were undertaken within 10 20 000 Hz using hydrophone recorders and applying “DNV shallow” test method. Measurement stations were placed along such shipping lanes, where the traffic is frequent. The station consisted of two hydrophone recorders. The movements of vessels were obtained from AIS system. Vessel passes which took place sufficiently close to the station were accepted and analyzed. So far, 645 passes have been analyzed. The database consists of 164 different vessels. The method will be applied in 6 more shipping lanes during 2026. The final database will be available in 2027.