Deployment Recommendations - Ocean Sonics Tow Fish User Manual

Appendix B

Deployment Recommendations

1. The Tow Fish is negatively buoyant and will sink when not being towed.
Rope length should be chosen based on water depth of the deployment area. If the
rope is longer than the depth of the water special care should be taken to ensure the
Tow Fish is retrieved before the boat slows to a stop, so the Tow Fish does not hit
bottom and cause damage to the equipment.
2. Increasing speed will increase the overall engine noise, flow noise and strum
recorded on the hydrophone.
The best data will be collected on the hydrophones while being operated at speeds
between 1 to 5 knots. Reducing speed will minimize flow noise, engine noise and
maximize the signal to noise ratio of your target sounds. Engine noise may be found
up to 10 kHz below speeds of 6 knots.
3. A Tow Fish Depth Calculator can be made in Microsoft Excel for quick depth
calculations.
By knowing amount of rope in the water, and the angle of the rope into the water,
the depth of the Tow Fish can be calculated.
4. The towline strain will increase as speed increases to a maximum strain of 40kgf
at 8 knots.
5. 3/16" Amsteel was used during testing of the Tow Fish.
Amsteel rope (or equivalent) with a smaller outer diameter will diminish sound from
rope strum and increase the Tow Fish stability.
Tow Fish User Guide April 2020 P.8