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                                                                     Tow Fish User Guide                                

 April 2020

             P.8 

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. 

Summary of Contents for Tow Fish

Page 1: ...Tow Fish User Guide April 2020 Version 3 0 Doc 12109...

Page 2: ...l with an autonomous or cabled deployment The Tow Fish is a towed underwater depressor designed by Dartmouth Ocean Technologies The Tow Fish allows users tow a hydrophone at a constant depth behind a...

Page 3: ...see below b Two bands on the hydrophone will line up with clamp positions on mount c Secure the hydrophone with the 2 top bands of the clamps and tighten the hex screws in place with a Hex Allen key...

Page 4: ...eye hook b If you are using cable grips loop the cable grips through the oval quick link a rope can be used as a secondary line 7 Ensure the rope and or cable grips are being used as the tension memb...

Page 5: ...ecommendation 3 for further details 6 Once the desired rope length is paid out the rope can be tied off to a midsection point on the vessel 7 Increase the vessel to the desired towing speed For best r...

Page 6: ...Tow Fish User Guide April 2020 P 5 Cabled Deployment...

Page 7: ...to the icListen hydrophone install the first cable grip 4 Place the cable grip over the end of the cable with the two loops closest to the connector 5 Push cable grip over the cable 6 Measure approxim...

Page 8: ...equipment 14 Place the cable grip over the end of the cable with the two loops closest to the connector 15 Push cable grip over the cable to the measured distance 16 Secure the cable grip with the two...

Page 9: ...ill 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 sound...

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