Deployment - Edgetech 3100 Quick Start Manual

3.0 DEPLOYMENT

Points to be considered for deployment of towfish:

The towfish must be kept away from the propeller to ensure the integrity of both the equipment
and the data. In shallow water deployments, it may be better to deploy from the side of the boat.

When deploying the towfish from the side of the boat, make turns so that the towfish swings
away from the propeller.

Do not step on the tow cable, and keep it away from sharp objects and heat sources.

Bending the cable to a radius less than 12 inches may cause damage. Do not bend the tow cable
sharply.

Using a secondary rope to tow the towfish is recommended to prolong the life of the cable. It is
also easier to tie a rope to the boat that the tow cable itself.
To deploy the towfish:
1. Vessel should be underway at slow speed (0-2 knots) or stopped in neutral depending on the
situation and conditions.
2. Slowly and carefully lower the towfish to a safe depth just below the propeller wash (2-3 meters,
depending on water depth). Do not to strike the towfish against the side of the vessel.
3. Normalize the gain by clicking the N icon button and observe the data. Adjust TVG manually as
needed to have a uniform display color.
4. Observe and track the first bottom return.
5. Once you are sure that you have detected the seafloor, carefully lower the towfish to the desired
depth (about 5m from seafloor is ideal).
NOTE: It is not always possible to achieve an ideal altitude. However,
good data can still be obtained by towing the tow fish farther away from
seafloor.
6. Check that DISCOVER is still tracking the bottom, and adjust the tracking parameters (Threshold
& Window as needed.
7. Increase the boat speed to the desired survey speed (normally between 3-5 knots) and re-adjust
the amount of cable out so that the altitude of the towfish is correct.
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