3.3
Deployment hardware
The anchoring scheme used is very dependent on the goals of the data collection in combination
with the deployment environment. Thankfully SoundTraps are more easily deployed than traditional
acoustic recorders due to their small size. A SoundTrap ST600
’s weight in water is approximately
1.2
kg.
Most often the hydrophone is located near the sea floor, using an anchored line. This involves
running a line between a heavy anchor weight and either a surface or sub-surface float. A sub-
surface float is often best, as it is less affected by weather/swell and is less likely to be tampered
with. The SoundTrap should be attached to the line a couple of meters off the bottom. The groove at
the bottom of the housing provides an attachment point for one cable tie. This cable tie should be
threaded through the associated hole so it cannot slip off. A second cable tie can then be used
around the top of the titanium section of the housings, below the locking screw.
Avoid
using the hydrophone cage as an attachment point. This is too close to the hydrophone and
will likely introduce unwanted noise into the recordings.
Be mindful that a taut line combined with strong currents may result in ‘cable strum’ which may
disrupt your recordings. In this case a rigid frame may be more appropriate.
Ensure there are no metal objects in close proximity (3cm) to the SoundTrap eg using metal brackets
or wire rope. Doing so may lead to galvanic corrosion of the instrument housing.
Don’t mount your SoundTrap so close to the sea floor that it may become covered in sand or mud.
This may also lead to corrosion and corrosion instrument housing.
3.4
Depth rating and PRV requirements
As supplied the ST600 is rated for deployment up to 200m depth. This can be extended to 500m by
adding a PRV safety valve. The safety value ensures the housing cannot become pressurised in the
event of a slow leak. Failing to use a PRV risks injury to the user when the recorder is brought back to
the surface.
PRVs must be purchased direct from Prevco USA, part code 03395-001
PRV Installation Procedure:
