Installation manual

Purse seine hydrophone installation

851-165187 / Rev.A

Coverage area, orientation and tilt

General

Once the fore and aft placement of the purse seine hydrophone

is decided, it is equally important to carefully consider its

horizontal and v ertical orientation. Hydrophone or ientation can

have a large influence on system performance.

The hydrophone’s beam sensitivity is concentrated within a 90_

horizontal and -30_ vertical sector. Both keel and hull

installations are to be located on the side of the vessel that the

seine is shot.

Note: These installation instructions and related drawings are for

vessels shooting and pursing to STARBOARD.

Horizontal coverage area

When the seine is normally located forward of the starboard

beam when pursing the following information should be taken

into consideration:

1 When the seine is pursed in the sector from approximately

000_ to 120_ relative to the bow, the hydrophone should

be installed at an angle of 70_ to the vessels centre line.

2 When the seine is pursed in the sector from approximately

030_ to 150_relative to the bow, the hydrophone should

be installed at an angle of 90_ to the vessel’s centre line.

The most important elements with regard to the horizontal

coverage area of the hydrophone are:

1 An unobstructed line-of-sight to the PI54 sensor(s)

attached to the purse seine.

2 The hydrophone is directed at the middle of the net when

pursing.

3 Two hydrophones may be used for applications requiring a

large coverage area.