How to read a fish finder??

[Texas Bass Pro]

I have a simple fish finder on my boat but I really don't know how to use it.  Can I get some help on this.

When the finder shows fish on the screen, how far out are they from your boat??

Here are some pictures of my fish finder.  Its pretty simple and cheap.

   

[Jared]

With your unit, and with most units, except side finiding units, when the fish enter the screen on the right side of the screen they are directly below your transducer.  As they move to the left side of the scroll with the scroll of the unit they are moving behind your transducer. That is how i have always understood it to be.

[Ouachita]

To see true fish arches you first must be boating at troll speed. Think of the transducer as being a flashlight with a wide beam. Only it's sending out sound. When a fish begins to draw on the right edge of the screen, it's just entering the sound "cone". If the fish is toward the bow, then the first sign of a fish puts that fish under the boat. BUT, if the fish is passing from behind the boat towards the bow, it'll still draw on screen the same as the first instance. All a sonar does is tell you how far away a fish is from the transducer, not direction from it. You won't know how DEEP it is for sure unless that fish passes into the very center of the cone. Sometimes they just graze the edge of it and appear much deeper than they really are.

Jim

[Texas Bass Pro]

I know this is going to sound crazy, but how fast is "trolling speed"?

[Texas Bass Pro]

So if you stop your boat on a certain spot on the lake and you first notice the fish on the screen and then you don't see them anymore, does that mean they were moving and are now gone or should they still be there.

[Jared]

That may be a question that is better left to the guys who know alot like Jim (Ouachita) and Tom (Oldschool) but I would think that the fish is off the screen either because it swam away or because you drifted off the mark.

[Ouachita]

Trolling speed, depending on where you are and species, is up to 3 mph for black bass, 2-3 mph for stripers.

When the boat is stopped, whether a bass is suspended or moving, it's likely to show up as a horizontal dash that blends in with debris, cover, structure. While the boat is stopped over it, if it does the moving, a line will draw on the constantly moving display. A 45 degree sloped line is almost always air bubbles that travel straight up, and at most chart speeds, that draws as a 45 degree slope. If there are many bubbles streaming out of a log then there will be one line for each bubble track, all perfectly parallel. If a bass swims up say at a 45 degree angle, the line might draw at 23 degrees from horizontal since the graph is moving constantly.

If you spook the bass by stopping over it you should see it make a sudden angled line. Bye Bass. "We stopped right over one, and he's GONE."

Jim

[Texas Bass Pro]

Thanks for the information Jim. 


Would it be good to throw a marker out where I saw those fish on my screen so I can come back and pick them off or would that scare them away?

[Ouachita]

I keep two kinds of markers aboard. If I see activity on bottom, I use one with a short anchor string (fluorescent green) so a sinker doesn't plop onto bottom and spook them. If suspended I'll toss a long stringed marker (orange) which would stay put better in wind. I toss behind me as soon as possible while still moving since I'm convinced stopping right over any bass can easily spook them. Then I circle back to relocate the fish and set a GPS waypoint. If it looks like a keeper spot I'll toss long stringed markers around the perimeter and fish between them. Then I take up any short stringed markers before they float away, then slip back up to the bass.

If there's some peculiar structure or cover down there that appears to attract bass, and the spot looks like a honey hole, when the biting stops I'll get right over the magic spot and make a 20 second waypoint so I can pinpoint it next trip.

Jim

[imonembad]

  When I flip shallow cover, 2 foot or less I always turn off my fish finder to eliminate any unwanted noise.

[Ouachita]

That's good advice. Many transducers make an audible clicking noise, heard when bringing the trolling motor mounted transducer onto the bow with the unit still sounding. If we can hear that tapping noise, bass can hear it and learn to associate that with being hooked. I "stop charting" whenever the depth makes sonar impractical, but leave the GPS on so I can make valuable waypoints to mark hot spots.

Jim

[imonembad]

  Jim, I was always told to lightly sand the scratches off of your transducer. Do you recomend this?

[Jared]

Ive heard to turn off the sonar/transducers in shallow water also.

Jim you say that your turn off the sonar but leave on the GPS. I wonder if that is possible with my new unit (LMS 520c) which is sonar and GPS? It has a through the hull transducer... does that make as much noise in the water as the hull/trolling motor mount type?

[Ouachita]

I use a very fine sanding cloth to polish the plastic.

All analog and first generation digital transducers make the tapping/clicking noise, some louder than others. With boat on the trailer turn the sonar on and listen to the transducer. There's a newer technology out, a special digital sounder, that should be quiet. Last time I looked those modules run about $300, so I doubt you got one. I doubt anyone except a deep sea research vessel has one yet. They require a $7,000 sonar unit to run them.

On a 520 with the sonar page in view just press MENU once and look half way down for Stop Chart. Press ENT to put a check in the box. That turns the transducer off but leaves the GPS going. I like to keep Trails going to make it easier to figure out where I was when sorting waypoints at home.

Jim

[Jared]

I use a very fine sanding cloth to polish the plastic.

what does that do and how often should you do it?

I like to keep Trails going to make it easier to figure out where I was when sorting waypoints at home.

omg I have so much to learn! Sorting waypoints at home? I have no clue what ya mean by that. I know what a waypoint is, but I have no clue what sorting them while at home does or the purpose for sorting them at all.