Newbie Fish Finder Question

b-rich

Cadet
Joined
Jul 10, 2010
Messages
11
I just bought a nice Humminbird 788 ci DI fishfinder. So i get that the sonar beam is 20 degrees .. but have a few questions:
1: I know it shoots 20 degrees to the right and left of the transom ... but does it do 20 degrees in back and front? Is it like a razor slice or a cone?

2: I saw a ton of fish, caught not a 1. I turned it to Max Mode and watched my lure drop right past several fish (used cranks, jigs, drop shots, rigs, etc.) but never got any bites. I was anchored and not moving. Could it be I was far to the right or far to the left of the fish? I kind of dont get where the fish is (right or left) of the beam.

3: how do you guys fish with them? Do you cruise over some fish ... then go a little past and cast to them? Do you drop jigs/plastics/drop-shots right under the boat? If you are fishing shallows for bass ... is a transom mounted FF even any use.

Sorry for all the questions ... just trying to educate myself without guessing,
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Newbie Fish Finder Question

Lesson #1: Locators LOCATE fish -- they do not make them bite.
Lesson #2: About 90% of what are identified as fish (via fish symbols) are not fish.
Lesson #3: Turn the sensitivity down
Lesson #4: Turn off fish symbols and use the sonar so it displays "arches" (read the instructions)
Lesson #5: That is why it is called "fishing" and not "catching". Catching fish is not a one technique works for all species. Some species you slow troll for, some you troll faster for, some you jig for, some you cast for, and sometimes you have to use all of these techniques to catch fish.

As for the 20 degree thing -- you are confused. 20 degrees right and 20 degrees left would be 40 degrees.
The 20 degrees refers to a cone with a 20 degree angle. Think of an upside down ice cream cone (one of the pointy ones). At one foot below the transducer the cone would cover very little area. At one hundred feet the area covered would be very large. So at that depth, if the locator is showing fish, they may be very far to the front, back or either side of the boat. If they are suspended fish then jigging along side the boat may mean you are very far away from them.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,369
Re: Newbie Fish Finder Question

I wouldn't leave the dock w/o a working sounder. Like going hunting with a blind fold on.

We do a lot of vertical jigging in the summer. We cruise around using 50 kHz (45 degree cone angle) looking for the fish. Then change over to split screen 200 kHz/50 kHz (8/45 degree) once we find the fish.

Running in both modes allows us to determine where the fish are in relation to the boat. In 25' of water the 200 kHz beam is only 3' in diameter while the 25 kHz beam is 22' in diameter. If the fish shows up on both screens, the fish is right under the boat. If the fish only shows up only on the 50 kHz screen, we know the fish are away from the boat. Watching both screens makes it very easy to park the boat right on top of them.

Once you know what you?re looking at you can also tell the fish?s orientation to the boat by the shape and size of the returns.
 

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: Newbie Fish Finder Question

The DI part of your FF is for identifing structure whch should hold fish. Getting the DI for goes the 83kHz wide beam which is more effective for finding suspended fish. 90% of my fishing involves finding good structure. I will verticle jig for smallies or walleyes in 15' or deeper water. You can watch the fish take the jig, but you can't make them. ;)
 

b-rich

Cadet
Joined
Jul 10, 2010
Messages
11
Re: Newbie Fish Finder Question

Thanks for explaining it like that. I know my manual mentioned the different modes for kHz. This will be kind of cool to mess arouns with and get good at using the electronics. Thanks again.


I wouldn't leave the dock w/o a working sounder. Like going hunting with a blind fold on.

We do a lot of vertical jigging in the summer. We cruise around using 50 kHz (45 degree cone angle) looking for the fish. Then change over to split screen 200 kHz/50 kHz (8/45 degree) once we find the fish.

Running in both modes allows us to determine where the fish are in relation to the boat. In 25' of water the 200 kHz beam is only 3' in diameter while the 25 kHz beam is 22' in diameter. If the fish shows up on both screens, the fish is right under the boat. If the fish only shows up only on the 50 kHz screen, we know the fish are away from the boat. Watching both screens makes it very easy to park the boat right on top of them.

Once you know what you?re looking at you can also tell the fish?s orientation to the boat by the shape and size of the returns.
 

b-rich

Cadet
Joined
Jul 10, 2010
Messages
11
Re: Newbie Fish Finder Question

Thanks man .. I will play around with the sensitivity and rely on the arches and kill the fish symbols. Combining this with the other advice I got will give me some good stuff to play around with and get better.
 
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