Specifications

BATS AND PORTABLE BATS INSTALLATION
2-1
2. INSTALLATION
This section includes instructions for implementing a 4213C Hydrophone mounting assembly, mak-
ing proper attachment of the 4113C Deck Cable and also the Transceiver side panel interface con-
nections.
Hydrophone bearing, X, Y, Z offsets and pitch/roll offsets are generally determined at the time of
installation. This section includes sample procedures for determining those offsets.
2.1 HYDROPHONE/INTERROGATOR INSTALLATION
The manner and location in which the hydrophone assembly is mounted on the vessel is the single
most crucial element in the overall performance of the tracking system. In choosing a mounting
location, the operator should keep in mind that the BATS is by nature an extremely sensitive
acoustic system. The hydrophone assembly must be in a position to "hear" the acoustic pulses
coming from the pinger, transponder, or responder in use. Mount the hydrophone as far as possi-
ble from noise sources, such as, propellers, thrusters, echo-sounder transducers, main engines,
generators and other underwater acoustic generating systems.
Ideally, the hydrophone should be mounted far enough from the nearest reflector to allow the di-
rect arrival of a signal from the acoustic source before a reflected signal arrives. The minimum
recommended distance between the hydrophone array and the nearest reflector (which is usually
to the vessel's hull or keel) is one meter*. It is also important to keep the hydrophone below the
level of the vessel's keel for 360-degree coverage.
System performance can be degraded by "multi-path" or underwater signal reflections and rever-
beration. To minimize the possible effects of multi-path, choose a hydrophone location that is as far
away as possible from any surface that would make a good reflector of an acoustic pulse. Any hard
plate or structure near the hydrophone has the potential to reflect pulses into the hydrophone. The
air-water interface is also an extremely efficient acoustic reflector. Avoid any mounting locations
that would place the hydrophone in the proximity of bubbles.
* 1 meter = (1.33 milliseconds x 1500 meters/second)  2 way travel time
Consult the nearest EdgeTech representative for additional information on a specific installation.
NOTE: In some applications even though the hydrophone is over one meter directly away from the
hull, a signal can be reflected from an area along the keel and arrive within 1.3 ms of the direct
arrival thus causing interference. In these instances the hydrophone should be lowered further
away from the hull.