# Sonar Information

Discussion in 'LOCAL SOUTH CAROLINA TALK' started by Sunbird, Dec 8, 2009.

1. ### SunbirdNew Member

Messages:
781
State:
Sandy Run,
Here is the formula I use to determine the width of my cone on the bottom. Depending on your cone angle, mine is 30 degrees, it is posssible to determine the width at any depth. Here is the formula.............oooh:

Tan a =x/h

X=h x (Tan a)
X=5' x Tan a (15 degrees)
X=5' x 0.02679
x=1.34'

Now I know this looks real odd to us Yahoosmen:crazy: but, I have broken it down into 5' incriments to understand. The 15 degrees is because the formula works off of right angles. You must multiply your answer x2.
Here is 5' incriments.
At 5' bottom viewed width is 2.68'
10' bottom viewed width is 5.4'
15' bottom viewed width is 8'
20' bottom viewed width is 10.7'
25' bottom viewed width is 13.4'
30' bottom viewed width is 16.1'
35' bottom viewed width is 18.8'
40' bottom viewed width is 21.4'
45' bottom viewed width is 24.1'
50' bottom viewed width is 26.8'

I am often asked this exact question so I thought I would figure it up for those who wanted to know.

Now that's BIG STUFF!!!:smile2:

2. ### Bill in SCNew Member

Messages:
4,451
State:
South Caro
Hmmm. I thought I remember a BOC member saying that the general rule of thumb was, with a 30 degree cone, a general width was basically the same as the depth reading. In other words, 25 feet deep would equal APPROXIMATELY a 25 foot width scan. I ain't too keen on math. So, are you saying to multiply your final answers by two, or are the figures you posted the final answers? If the answers you quoted were multiplied by two, then that would fall just about in the range that I was quoted here on the BOC.

BB in SC

Last edited: Dec 8, 2009

3. ### catwhisperNew Member

Messages:
456
State:
georgia
so at 50 ft a 26.8 ft diameter times two correct?

4. ### Bill in SCNew Member

Messages:
4,451
State:
South Caro
That is what I want to know too.

5. ### SunbirdNew Member

Messages:
781
State:
Sandy Run,
Mama Sunbird took it to one of her Physicist today to make sure the formula and calculations were correct, He agreed. I will get her to run it by a different Dr. tomorrow to make sure. The figures are correct as listed. The actual width is approx. HALF the depth.

6. ### SunbirdNew Member

Messages:
781
State:
Sandy Run,
Remember the formula works off of right angles only. Look at the original equation. It is 15 degrees; half of 30.

7. ### catfishinscNew Member

Messages:
507
State:
SC
I didn't check them all, but the 5 ft is right. The rest look to be in line. In order for the diameter of the cone at depth to have the same diameter as the depth it would have to be a 53.13 degree cone.

8. ### Bill in SCNew Member

Messages:
4,451
State:
South Caro
Cool, good info.

BB in SC

9. ### nanny patrolMember

Messages:
389
State:
SC
Now thats useful info. Thanks

10. ### BigBirdNew Member

Messages:
2,104
State:
Charlotte, NC
dang all this math is getting me all excited.:tounge_out:

What would the depth be in 15' of water with a waffle cone?:crazy:

11. ### Bill in SCNew Member

Messages:
4,451
State:
South Caro
Depends on which end of the waffle cone is pointed downward! :smile2::wink::smile2:

Bill in SC

12. ### BigBirdNew Member

Messages:
2,104
State:
Charlotte, NC
Thats Big Stuff Math right there!
I would check your math but not going back to look up tangents....lol!oooh:

13. ### striper steveNew Member

Messages:
50
State:
south carolina
impressive math but according to the lowrance website the answers may not be right. it gets kinda complicated but according to them a 20deg angle may show up to 60deg because of the way manufactures measure the angle. if you go to the lowrance site and look under sonar tutorial it explains it alot better than i can. ive been told that with a 20deg you see aproximately 1/3 depth(just what ive been told) but apparently thats incorrect as well.

14. ### SunbirdNew Member

Messages:
781
State:
Sandy Run,
I know what Lowrance says and if they have 'secret' technology working to enhance the coverage zone then what they say is true. I have merely taken the equation for determining the coverage at certain depths and worked them out. I have figured up the coverage numbers for a 20 degree cone also.
5' it's 1.76'
10' it's 3.52'
15' it's 5.28'
20' it's 7.05'
25' it's 8.82'
30' it's 10.58'
35' it's 12.34'

There may infact be funtions of the cone angle that, can and are, manipulated by Lowrance to enhance coverage. I don't know. I just thought it useful information for the Yahoosmen!!:wink:

15. ### screamnclickerscNew Member

Messages:
755
State:
S.C.
Sunbird you got too much spare time:wink:

16. ### skiff1New Member

Messages:
210
State:
south caro
Its pretty confusing but it seems like you don't cover much area.

17. ### nevets91New Member

Messages:
604
State:
rock hill south carolina
how did you even come across that formula. thats pretty interesting though i started doin the formulas to work for mine(20 degree cone) but then realized you did it already.ill have to remember that info

18. ### gotta goNew Member

Messages:
2,395
State:
SC
I really don't worry about it cause all them blame thangs tell you lies. I had fish all under the boat and didn't get a bite but i was out there drifting and it wasn't showing up one single fish and i caught a 50lb flathead, same thing at wateree, no fish on fishfinder and i caught fish.:smile2: soo all this formula stuff is just to get you to think they know what they are talking about to get you to buy one just cause your friends have got one.oooh:

19. ### katman#1New Member

Messages:
1,209
State:
South Carolina
thanks sunbird for the useful post

20. ### slojamNew Member

Messages:
181
State:
scarolina
useful&correct mathmatically.i have a lowrance i need to install&put to use. maybe someone will try to validate the 60 degree claim by lowrance.(hopefully it's true) lot of difference between 20&60 degrees.thanks again