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How to read a fish finder??

36K views 52 replies 9 participants last post by  Ouachita 
G
#1 ·
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.​





 
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#2 ·
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.
 
#3 ·
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
 
G
#5 ·
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.
 
#6 ·
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.
 
#7 ·
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
 
#9 ·
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
 
#11 ·
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
 
#13 ·
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?
 
#14 ·
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
 
#15 ·
Ouachita said:
I use a very fine sanding cloth to polish the plastic.
what does that do and how often should you do it?


Ouachita said:
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.
 
#16 ·
Sanding a transducer is for modules mounted on a trolling motor. They get scratched up on rocks. Scratches collect dirt and that kills signal. They need to be kept clean with nothing but plastic showing.

I use a Lowrance program called Map Create http://www.lowrance.com/Products/Mapping/MapCreate7/default.asp I transfer a copy of waypoints in the head unit on the boat to a memory card, which your 520 will do. I then read the data into Map Create. With Map Create I can go back and study the new waypoints. I like to take a close look at why a spot was a good one. To do that I put my Lowrance map card in the reader so I can view the lake contours on the pc. I can then see the waypoint over the topography.

It doesn't stop there. I have two LMS 332Cs, the older version of what you have. On the bow unit I keep a blank memory card in the card slot. I "Log Sonar" on the card. That's a running record of everything your sonar displayed even when you were not looking. I can then read that data into the free downloadable Lowrance Sonar Viewer http://www.lowrance.com/Downloads/SLV/sonar_viewer.asp and watch the day's sonar to pick up lots of information about where I was. Because you have GPS the Log Sonar also collects GPS positions which show on the screen with the sonar. If you see something interesting you stop the chart from moving and place mouse point over say a big stump with a couple of bass next to it. It gives you the exact coordinate of that stump as well as depth and all the details you should have seen live while fishing.

Jim
 
#17 ·
Ouachita said:
Sanding a transducer is for modules mounted on a trolling motor. They get scratched up on rocks. Scratches collect dirt and that kills signal. They need to be kept clean with nothing but plastic showing.
oh ok thank you Jim. That makes a lot of sense to me :D
 
#18 ·
Ouachita said:
I use a Lowrance program called Map Create http://www.lowrance.com/Products/Mapping/MapCreate7/default.asp I transfer a copy of waypoints in the head unit on the boat to a memory card, which your 520 will do. I then read the data into Map Create. With Map Create I can go back and study the new waypoints. I like to take a close look at why a spot was a good one. To do that I put my Lowrance map card in the reader so I can view the lake contours on the pc. I can then see the waypoint over the topography.

It doesn't stop there. I have two LMS 332Cs, the older version of what you have. On the bow unit I keep a blank memory card in the card slot. I "Log Sonar" on the card. That's a running record of everything your sonar displayed even when you were not looking. I can then read that data into the free downloadable Lowrance Sonar Viewer http://www.lowrance.com/Downloads/SLV/sonar_viewer.asp and watch the day's sonar to pick up lots of information about where I was. Because you have GPS the Log Sonar also collects GPS positions which show on the screen with the sonar. If you see something interesting you stop the chart from moving and place mouse point over say a big stump with a couple of bass next to it. It gives you the exact coordinate of that stump as well as depth and all the details you should have seen live while fishing.

Jim
Wow that sounds like a lot of fun to be able to do that! I just checked on the prices for the Mapcreate 7 and it looks like it runs about 100 bucks. I figured from the sound of it it would be a couple hundred dollars. I believe I will save up and try to get it one day. Id like to also g et a good map pack for the unit. Which do you recommend Jim? There seems to be a few different ones. Id like to get the one with best contour lines I can get for the lakes in my area (SC) atleast, if not a broader area.
 
#19 ·
I have recommended Don Iovino's book Finesse Bass Fishing & The Sonar Connection because I use it for a reference guide to set up way points and optimize my sonar unit. Ouachita, Jim, is a wonderful source for information and I'm sure when he gets around to publishing a book it will be great resource and looking forward to that. Until then everyone interested in learning sonar and or finesse bass fishing should consider Don's book. Iovino is a certified Lowrance factory representative and bass pro sponsored by them.
http://www.iovino.com/donbook.htm
Tom
Ps; I'm not trying to promote Iovino's products, this is the best available book on this topic that I know of. This book saves me a lot of time on the water.
 
#20 ·
Lowrance http://www.lowrance.com/Products/Mapping/hotspotsPRO/default.asp has a cheaper map card selection, but all their maps are based on paper maps and some on recent sonar surveys by the government and whatever other sources they could get. Check them out to see if your lakes are listed. Navionics http://www.navionics.com/HMPremium_07.asp offers many lakes now in HD, high definition live sonar surveyed lakes with 1 foot contour intervals if you zoom in close enough. I highly recommend those if your lakes are covered. If not save money and go with Lowrance maps. Lowrance doesn't survey lakes.

You might find some free E-maps to try out, downloaded at http://www.lowrance.com/Products/Mapping/LakeMaps/index.asp

Jim
 
#21 ·
Another of my favorite sources besides Iovino's book is some videos on DVD from Doc Samson at http://www.hightechfishing.com I have the last 3 videos, and look forward to the next which will be underwater camera views keyed to sonar screen shots with descriptions. Doc is not a great speaker, just a plain spoken tournament angler (retired medical doctor) that knows his stuff. On that website are several free lessons about sonar and GPS. You need Iovino's book to learn about finesse fishing, especially in deep western reservoirs.

Jim
 
#22 ·
thank you guys for the usueful info. :thumbup01:
I plan on getting Dons book the first chance I get. Ive got a nice unit now but its useless if i dont know how to use it to its fullest capacity.
 
#25 ·
20 second waypoint: When you punch WPT on the head unit face it begins taking GPS positions. Most folks close it in a second or two. A drop-down message allows some options. One is "Average Positions". I select that and let it take a number of positions. The best average position is calculated using the strongest satellite signals. That gets accuracy way closer than the usual 3 meters. 30 seconds often gets within 5 feet of actual position. You can test that by setting up over a land survey monument, calling a state or city surveyor office for the coordinates of it. A 20 second waypoint is close enough. If it's windy it's a little hard to hold the boat in one position long enough for a 20 second averaged position, so I take whatever I can before moving off target.

While taking the positions take time to punch in a peculiar name for the spot. You have to scroll through the alphabet and numbers 0-9 for each character. Use the arrow keys to move to the next character. I plan on writing up an article about this, but for now I recommend making up a naming system. I might name a waypoint "06smr30". That stands for 6' depth during spawn on March 30. Other bass seasons would be p for pre spawn, ps for post spawn, s for summer, f for fall, w for winter. All waypoints made on lake Ouachita are kept in a computer folder named Lake Ouachita. Later I can cut out some waypoint files pertaining to the spawn season only and load only those into the boat unit.

I have many routes named and stored also. One is a night route just for navigating quickly from one end of the lake to the other, dodging hazard areas. There are sub routes coming off that one that will take me directly to ramps or marinas. There are several milk run routes based on bass season. Each route links favorite waypoints. I like to remove all waypoints and routes from the head unit and only load what I need for the period.

Jim
 
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