Installation manual

Purse seine hydrophone installation

851-165187 / Rev.A

Dual hydrophone installation

Large vessels and operations requiri ng a greater than normal

coverage area can install two hydrophones with a vertical and

horizontal overlap. Hydrophone selection is made with the help

of a switch located in the wheelhouse.

To r educe the possibility of interference from air bubbles and

underwater noise when reversing propulsion or using thrusters

the two hydrophones should be located at least five meters from

each other in the fore and aft plane. It is also recommended to

install the two hydrophones with a slightly different tilt angles

so that a larger vertical sector may be covered. Vessels equipped

with a bowthruster or bulbous bow can install the first

hydrophone forward of the bowthruster on the bulbous bow and

the second aft of the bowthruster. Dual hydrophone installations

may be either keel mounted or installed in free-standing blisters.

Horizontal coverage areas

When the seine is normally located forward of the starboard

beam when pursing the following information should be taken

into consideration:

• When the seine is pursed in the sector from approximately

000_ to about 130_ relative to t he bow, the foremost

hydrophone should be installed at an angle of 50_ and the

after 90_ to the vessel’s centre line.

• Should special circumstances require coverage outside the

standard 000_ to 130_ sector the hydrophones may be

installed accordingly.

(A) = Aft hydrophone, (B) = Forward hydrophone