Finland – Hydrographic instruments – Hydrophones and compatible release units

Please note that this is a prior infromation notice and this notice is not a call for tenders. The information provided in this notice is preliminary and may change as the preparation progresses. The Natural Resources Institute Finland (Luke) is planning to purchase hydrophones and release units. Hydrophones are needed for ringed seal research conducted in the Baltic Sea and Lake Saimaa to record underwater calls produced by ringed seals and the underwater soundscape. The specific requirements for the hydrophones are: • Low power consumption, very low self-noise and 60 kHz bandwidth • Long battery endurance lasting up to 160 days • Must be able to provide up to 2 TB of removable data storage • Recording bandwidth of 20 Hz – 60 kHz • Sample rate of up to 192 kS/sec • Must provide a durable titanium housing • Must contain a removable protective hydrophone cage • Must be able to operate in depths of several hundred meter - up to 500 m depth rating • Must be suitable for up to 1 year deployments In addition, the hydrophones cannot be retrieved from depths by diving; thus, a remote release mechanism that brings the hydrophone up to the water surface is needed to accompany the hydrophone. The requirements for the release unit are: • Must be compatible with the hydrophone type used in the project • >13 months deployment with alkaline battery pack • Integrated inclinometer • Uses a storage mode eliminating power consumption when not in use • Reliable, 'screw-off' release • Rugged, compact design • Working Load Limit of 150 kg • Depth rated to 1,000 m In addition, a control unit is required to control and operate the release unit.