Klein 5000 V2 Series, Operation And Maintenance Manual

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A-1
APPENDIX A: S
AMPLE
T
OWING
C
HARACTERISTICS
Five towing characteristic graphs are included in this appendix as Figure A-1
through Figure A-5. Two of the graphs were generated without any additional
weight being added to the towfish, and the other two graphs were made with our
K-Wing II Depressor attached to the towfish. We believe you will find these
graphs helpful in planning your surveys and equipment requirements.
As with any projections of this type, certain conditions and assumptions were
made in order to generate a reasonable quantity of data with some degree of
accuracy. Read all the conditions below before you attempt to use the data.
Data.
Data were computer generated using programs of known prediction
accuracy in both military and commercial towing systems. At best this type of
data provides "ballpark" values versus absolute values. These curves have been
checked with field data wherever possible. At best the values are within 15%
accurate with the greatest accuracy at towfish depths between 91 m (300 ft)
and 914 m (3000 ft) and at tow speeds of 3 to 7 knots. They are least accurate
at slow speeds and short cable lengths.
Tow Cables.
Tow cables having the characteristics below were used. Should
you have a different cable, it could make a significant difference.
• 10.2 mm (0.40 in.) nominal diameter double armored, galvanized steel;
weighing 353 kg per 1000 m (237 lb per 1000 ft) in air; 353 kN (11,000 lb)
breaking strength.
• 17.3 mm (0.68 in.) nominal diameter double armored, galvanized steel;
weighing 1030 kg per 1000 m (692 lb per 1000 ft) in air; 178 kN
(40,000 lb) breaking strength.
Cable drag increases with increasing cable diameter. The drag increases as the
velocity squared (V
2
). As cable weight per unit length increases, the cable tows
deeper.
NOTE
Depressors have minimal effect at speeds of 2 knots or less. Boat
motion plays a large role in shallow towing. For very deep towing, ocean
currents can completely change the cable characteristics.