·
·
·
Put the shackle through the steel cable “towing eye”, at
the end of the strain-relief on the towing-cable.
Position the shackle over the middle towing hole on the
StarFish, and as you do, ensure that the towing cable
passes under the shackle.
Secure and lock the shackle in place with its pin, and the
circular securing ring.
START SCANNING
Do not rely on the connection between the towing cable and
the electronics box to secure the StarFish transducer, as
during towing there is significant force on the cable, and the
electronics module with attached computer may be dragged
overboard!
Read the section in the “System User Guide” on
avoiding hazards.
You should not rely on the sonar as a navigational aid
for your vessel, or for avoiding shallows, submerged or
mid-water hazards.
Once you've connected and set-up the sonar as described in the
previous sections, you're ready to start towing the sonar and
begin collecting data.
Towing the sonar is relatively straightforward, but there are a few
guidelines and precautions you should observe to achieve the
best results…
·
·
·
Do not bend the cable to a radius less than 30mm, as this
may shorten its life.
Do not use a fixing method, that will cut or damage the
cable
Do not use a securing method that excessively crushes
the cable.
·
·
·
·
·
·
·
·
Let the boat build up speed to 1-2 knots before putting the
sonar in the water.
Keep the boat speed constant, and ideally between 1 and 4
knots for the best results.
When towing in rivers and tidal channels, remember that the
speed of the water current should also be taken into account.
The faster the water travels, the more force is exerted on the
sonar. The recommended maximum towing speed is 8 knots.
Tow the sonar from the stern of your boat.
Tow the sonar away from the prop-wash (to one side of the
boat, for single propeller vessels).
Paying out more cable will cause the sonar to dive deeper,
with the exact depth depending on tow speed.
Tow with enough cable so the sonar is operating below the
keel of the boat, but try and keep the sonar at least 3 meters
above the seabed (or higher in known rocky situations).
·
·
Wrap the cable round a bollard, capstan or cleat that has
a diameter larger than 60mm.
Using slip-knots, tie a soft rope to the cable, then tie the
other end of this to the boat.
Depending on the salinity of the water and the towing
speed of the sonar you may find that you need to adjust
the towing position backwards from the middle towing
hole to achieve the best results.
However, only the three central holes are intended as towing
points (the outer holes are for use in transit and the
attachment of accessories).
Moving the towing position backward, makes the sonar to
become nose heavy, causing it to dig into the water more,
increase the tension on the cable, and go deeper.
If the sonar is too nose heavy, it will flip and drag
vertically.
Moving the towing position forward, causes the sonar to tow
more horizontally.
If the sonar is too tail heavy, it will try to swim
upwards and sideways
Make nose
heavier when
towing
Make tail
heavier when
towing
Towing Holes
SET-UP THE SONAR
Pin
Securing
Ring
Cable
(under link)
Shackle
Body
Ideally, either...
SECURE THE SONAR
P/N: BP00058.4
UM-103-P00058-04
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