flasher angle, do I need a dual beam?

[pyro30244]

I only go into deep water once or twice a year. Would a 20 degree transducer be completely useless in 100 feet of water with a flat bottom?

I've got a tight budget. I'm looking at the marcum M1 (20 Degrees) or The hummingbird Ice-35 (19/9 degrees). The hummingbird is even a bit cheaper.

This post has been edited by pyro30244 on Dec 29, 2018 - 05:27 pm

[Sharkbait22]

20 degrees is fine but there will be lots of fish on the screen that are not necessarily near your lure. Also lakers are often higher up in the column so a 20 is better for that. At that depth a 20 degree angle means about 30 ft will be seen. Flat areas would be best so stay away from slopes. Ideally you can vary cone angle like on the Garmin (GT8HW 16-24 or GT10HW 7-16) and Marcum (8-20) units.

Deep water fishers are a minority. Most sonars are set up for 25ft or less it seems. Worst is the small screen height of today's units. Try fishing 100 ft of water column on a 2.X inch high screen! Split screen zoom ok but just how much history to you need! I wish I could rotate my head unit/screen and view it vertically. They could also bump up the screen resolution 800x400, my phone has 2900x1440 and it is 1-2 ft from my face.

Some transducers and coverage at depth.

Lowrance x67c
Cone angle 20 degrees.
Depth ft Dia ft
10 3.5
20 7.0
30 10.5
40 14.0
50 17.4
60 20.9
70 24.4
80 27.9
90 31.4
100 34.9

Marcum x7
At 8 degrees
Depth ft Dia ft
10 1.4
20 2.8
30 4.2
40 5.6
50 7.0
60 8.4
70 9.8
80 11.2
90 12.6
100 14.0

GT10HN
At 7 degrees
Depth ft Dia ft
10 1.2
20 2.4
30 3.7
40 4.9
50 6.1
60 7.3
70 8.5
80 9.8
90 11.0
100 12.2

[Fisherman]

Thanks for those numbers. I'll have to print that off and plasticote it.

[pyro30244]

I appreciate the info sharkbait. Thanks.