Math question

[mike a]

I figure there’s got to be some fishermen on here. So, I just got my first ever fish finder. Garmin Striker Vivid SV 9”. I’m not sure I’ll be keeping it. Sense I only fish ponds and small lakes ( shallow water ) I’m concerned that it may be only looking at a tiny patch of water. Here is a calculation I found online but I aint scrooled enough to figure to out. So, I’m looking for cone size down to 10’ with 24 degree angle. If you could show your math that would be nice. Cheers Mike

 

[mike a]

My boat. With a Forest Gump accent.

 

[Buttstock-TX]

If the Angle is 24 degrees:
Diameter = 10 * 2(tangent 24/2)
Diameter = 10 * 2 * 0.1908
Diameter = 3.82 ft

 

[mike a]

If the Angle is 24 degrees:
Diameter = 10 * 2(tangent 24/2)
Diameter = 10 * 2 * 0.1908
Diameter = 3.82 ft

WOW, Thanx buddy. That sure is a tiny patch of water. And that’s on the bottom! At 5’ alot smaller.

 

[itchyTF]

If my numbers are correct I get 4-1/4 feet.

 

[itchyTF]

Mmmmmm, on my phone calculator the tan of 12 is .212.

 

[Buttstock-TX]

Yes, it is, for some reason my computer calculator originally gave 0.1908. When I did it again it came out as you say, 0.2126. So,
If the Angle is 24 degrees:
Diameter = 10 * 2(tangent 24/2)
Diameter = 10 * 2 * 0.2126
Diameter = 4.252 ft

Still pretty small!

 

[ChristianSilver]

24Sin x 10’ = 4.06’ everyday all day..

 

[itchyTF]

Don’t believe the hypotenuse is used here. The 10 ft would be straight down and would correspond to the adjacent in a 12 deg triangle.

 

[Ranger188]

So your seeing a very small part of the bottom.
Just asking, why do you need a sonar in that shallow of water, is it that murky?
In early spring or late fall the water might clear up enough for you to see
what you need for the rest of the year.
Or use it to find depth contours right now and remember them or right it down
if you are going to return it.
A lot of places won't take electronics back.
What type of fish are you going after?

 

[ChristianSilver]

Don’t believe the hypotenuse is used here. The 10 ft would be straight down and would correspond to the adjacent in a 12 deg triangle.

Has nothing to do with hypotenuse in that example..

I misinterpreted the question.
Sin of an angle x distance equal’s distance moved off of a straight path or center.

A cone of 24 deg will have a coverage, radius of 4.1582’ in 10’ of water, depth whatever you call it.

 

[Coyotefurharvester]

That's why side view was invented.

 

[1911nut]

What about side imaging sonar?

 

[itchyTF]

Has nothing to do with hypotenuse in that example..

I misinterpreted the question.
Sin of an angle x distance equal’s distance moved off of a straight path or center.

A cone of 24 deg will have a coverage, radius of 4.1582’ in 10’ of water, depth whatever you call it.

Not to beat this to death, but a picture would be helpful however it’s midnight here now. I still hold to 4-1/4 ft diameter.

 

[ChristianSilver]

12 deg sin = .2079 x 10” = 2.0791 x 2 = 4.1582’

 

[V35]

Can you change frequency? Every graph I have owned produced a wider cone on lower frequency. I have never owned a Garmin, so I cant say for sure, but Hbird, Lowrance and simrad are that way.

 

[CJ6]

FFS...Read what the instructions say

 

[Uncle Grinch]

Hummm… 4.1 feet. Kinda like shooting fish in a barrel.

 

[jwink]

The one thing I've learned with my graph is that it is called fishing for reason, you can see them, but it doesn't mean you can catch them. Unless you are using those round red lures lures with the fuses hanging out the one end of course.

 

[BoydAllen]

4.25’ Section the cone vertically, then cut the resultant isosceles triangle in half producing a right triangle with the smallest angle of 12 degrees, and the adjacent side of 10’. Solve for the opposite side from the angle using the tan of 12 degrees, .2125 x 10 and multiply that by 2. Note: I corrected the decimal placement of the Tan of 12 degrees. Haste makes stupid.