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 descent, take the guess work out of donwrigger fishing. Consult the chart below to understand the relationship between the angle of descent 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 descent, 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 of descent 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 |
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