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Knowing
the exact Depth and Lateral Location of a Subsurface bait or lure
is critical in making the presentation most effective. Simple
calculations of tow cord length, based on varying angles of decent,
take the guess work out of donwrigger fishing. Consult the chart
below to understand the relationship between the angle of decent
and the length of tow cord needed to attain the desired depth.
|
Desired Depth
|
Angle of Decent
|
Tow cord Length
|
Factor
|
|
10 feet
|
16 degrees
|
10.3 feet
|
.96
|
|
10 feet
|
20 degrees
|
10.6 feet
|
.94
|
|
10 feet
|
30 degrees
|
11.5 feet
|
.87
|
|
10 feet
|
40 degrees
|
13.0 feet
|
.77
|
Based on the above factors and the varying angles of decent, one
can calculate the exact amount of tow cord necessary to reach
the desired depth by performing the following exercise. Please
be sure to calculate the free board of your boat in to the equation.
Desired depth / factor ( associated with angle of
decent ) = Tow cord length
For example: Desired depth = 75 feet and we have
a 20 degree angle of decent.
75 / .94 = 79.8 feet of tow cord
At a 30 degree angle of decent the formula would look like this:
75 / .87 = 86.25 feet of tow cord
A steaper angle fo decent allows for less tow cord to attain the
same desired depth. Since the Z-wing Downrigger will maintain
depth and lateral location over a range of speeds, no adjustment
in tow cord length is necessary to maintain desired depth.
LENGTH OF TOW CORD CALCULATIONS
|
|
16 degrees
|
20 degrees
|
30 degrees
|
40 degrees
|
|
10 feet
|
10.3 FT
|
10.6 FT
|
11.5 FT
|
13.1 FT
|
|
20 feet
|
20.6 FT
|
21.2 FT
|
23.0 FT
|
26.2 FT
|
|
30 feet
|
30.9 FT
|
31.8 FT
|
34.5 FT
|
39.3 FT
|
|
40 feet
|
41.2 FT
|
42.4 FT
|
46.0 FT
|
52.4 FT
|
|
50 feet
|
51.5 FT
|
53.0 FT
|
57.5 FT
|
65.5 FT
|
|
60 feet
|
61.8 FT
|
63.6 FT
|
69.0 FT
|
78.6 FT
|
|
70 feet
|
72.1 FT
|
74.2 FT
|
80.5 FT
|
91.7 FT
|
|
80 feet
|
82.4 FT
|
84.8 FT
|
92.0 FT
|
104.8 FT
|
|
90 feet
|
92.7 FT
|
95.4 FT
|
103.5 FT
|
117.9 FT
|
|
100 feet
|
103.0 FT
|
106.0 FT
|
115.0 FT
|
131.0 FT
|
|
|
