Fish finder

[8x56mn]

I have a question regarding the adjustment of fish finders. I have recently installed my first fish finder on my boat, it's a Lowrance 125 with speed. When I'm fishing I can see my downrigger ball when I have the Fish ID on, but when I switch to the other mode (arch) I do not see fish arches. I believe that I have the transducer pointed back too far can this be the case. Do you guys set yours so you can see your bait or should I point it farther ahead. Why doesn't the downrigger ball show as an arch when it's in that mode.

 

[JB]

Re: Fish finder

Electronics topic

 

[JAG59]

Re: Fish finder

What, exactly, do you mean by "pointed back too far"? I recently installed a Hummin' Bird (my first also)on my boat. The instructions say to mount it on the bottom edge of the transom. My transducer only has an adjustment for height and angle. Sometimes, getting fish to show as arches has a lot to do with resolution and your sensitivity setting. Lowrance has a really good tutorial site that helped me understand some of the basics. http://www.lowrance.com/Tutorials/Sonar/sonar_tutorial_01.asp

 

[jtexas]

Re: Fish finder

Your downrigger ball won't show as an arch because its position relative to the transducer is constant - it should draw a straight line across the screen. <br /><br />With fish ID on, the computer will usually interpret most any echo between your boat and the bottom as a fish and draw the little fish symbol. Fish ID off, you just see the raw sonar returns. The size & shape of an arch depends on the size & speed of the fish and the path it takes under your boat - if it turns or ascends or descends, you'll get a partial arch.<br /><br />If your transducer is not pointed straight down at the bottom, your depth reading is wrong - the bottom is farther away from the 'ducer if it's pointed out away from the boat.

 

[Boatist]

Re: Fish finder

I agree with jtexas. The transducer should point straight down or up to 2 degrees foward. If you point it back as you suggest then the back of the transducer will be higher than the front. This will cause turbulance and it will likely not work at higher speeds. I would never use fish ID mode. All it does is display every thing off the bottom as a fake fish. That fish could be a leaf, plastic bag, tree lime, moss, or a little muddy water.<br /><br />Run in raw or arch mode. Turn the sensitivy up until the until you have many false return in the depth you are fishing. Top part of the screen may be almost solid black from surface clutter to get good returns from a depth of 25 feet. Remember also your unit has a 20 degree 200KHZ transducer so even at 30 feet deep on the bottom the transducer only see a 10 foot circle. At 15 feet it is a 5 foot circle. By turning up the sensitivy you can see a little wider area. Lowrance say up to 60 degrees but I think unlikely because the returns in the center would be so strong the screen would black out.<br /><br />If you do see the downrigger ball as long as it is at a constant depth it will be a straight line. Any thing that pass thru the transducer center will arch if it stays at a constant depth. A fish swimming under the boat at a constant depth will also be a straight line.<br /><br />Length of the arch has nothing to do with fish size. A long arch just means the fish was under the transducer longer. a 6 foot Sturgeon will take longer to pass under the transducer so it would be longer. However a 6 inch bass swimming under the shade of the boat could look even longer. I find the best way to determin size is by the height of the return. Larger fish will also show gray line or fish cavities.<br /><br />The deeper your down rigger ball the eaiser it is to see as the cone gets wider at the bottom.

 

[8x56mn]

Re: Fish finder

Thanks, I did look at the Tutorial and it was helpful for sure. I fish deep water in Seneca lake and I run my downrigger balls at 100 feet and as you say I see a straight line wish fish ID off and a little fish symbol followed by a smaller fish symbol that I believe indicated the lures. I never seem to get the arches though, I'm trolling so any fish should be an arch correct when the Fish ID is off. The tutor also said to run the graph speed at 3/4 I still have to check that next time out. I have been running it in Auto Mode as well.<br /><br />I have been catching fish on my meat rod, but I never see fish unless I run the Fish ID. and I thought perhaps I had the unit tipped up at the rear too far because I am seeing the ball. I read somewhere that some guys do that so they can see there DR ball and be able to set their depths correctly. My boat is a little stern heavy so it was tough to set the angle while on land and I just kind of guessed at what would be level when it was in the water. I can adjust it from the stern, but how can one really tell if it's correct, the tutorial never really address this problem. Please help

 

[jtexas]

Re: Fish finder

I just eyeballed mine on installation - then checked it in shallows with a fishing rod. Or compare depth readings with other boats on the water. There's a depth offset adjustment - where if the 'ducer is a foot under the surface it'll correct for that. <br /><br />Aiming the transducer at the d/r ball is a pretty good reason to mount it at an angle - if the downrigging experts advise it. But it'll just give you distance from boat to ball - which won't be the depth. At 100 feet you're getting about a 30 foot diameter - 15 feet behind the boat - not sure how far back it'll get.<br /><br />Here's a couple pics of schooling fish on an Eagle 320, which I think yours has even better resolution than this. Isn't the 125 equivalent to the eagle 480?<br /><br />

<br /><br />

<br />(these are from a local fishing guide, John Varner, don't think he'll mind me linking to his pics)<br /><br />The fish are white bass & hybrid white bass mostly around 14 - 16 inches, couple pounds, could be some up to 6 or 8 pounds in there maybe - I think heavier fish return a stronger signal & draw a thicker line - but I couldn't swear to it.<br /><br />The screen is zoomed in to the bottom 1/4 of the water column - with it zoomed out the arches are much smaller. The boat is drifting - at trolling speed the arches get smaller due to fish spending less time under the boat. Selecting a faster ping speed is supposed to help correct for that. But if you troll over a school you should be able to recognize it as fish. Looking to 100 foot depths, I agree with boatist, turn up the sensitivity.

 

[imported_bjs]

Re: Fish finder

i have a 320 i just put mine on auto works fine if you point the transducer straight down you get a false depth reading dont you.mine points straight forward.mine dont always so fish archs.but on those days i dont catch any fish either.keep me informed maybe your info might help me and others.

 

[Boatist]

Re: Fish finder

If your running your downrigger at 100 feet then you should have the sensitivity up high enough that the top 30 feet or so are all black from surface cluter. You can turn it up in auto mode or you can go to manual mode. Try turning it all the way up in auto mode first.<br /><br />A fish is like a stealth fighter, wedged shaped and it deflects signal off to the side so you have to turn the sensitivy way up to see deep fish. If I am fishing 100 feet deep then I turn the sensitivy up until I get false returns in that area. about the top 1/3 of the screen will be blacked out from surface clutter but that is ok. In the sample below this I would still turn the sensitivity up more.<br /><br />I big flat rock will give you a return at low sensitiviy but not a fish.<br /><br />In this example they have the gray line set about right. If gray line was off then the area A would be all black from surface clutter.<br /><br /><br /> http://www.lowrance.com/Tutorials/Sonar/sonar_tutorial_11.asp

 

[8x56mn]

Re: Fish finder

Thanks again for the help. When I say point straight down, I'm quoting what the book says. The term is misleading as you don't actualy point the point the transducer, it means the underside (flat portion) should be parallel with the bottom, by tipping the back upward that is pointing it back, so as to see more of what you just passed by, pointing back would give you more of what's coming, but not see your down rigger ball. I also have a feature called double transducer with allows me to show a split screen with 30hz power on the left and 200hz power on the right, this is supposed to allow me to see the ball at lower power, but I couldn't seem to get this to show me what I was looking for.<br />I will try to play around with the sensitivity next time out along with chart speed and see what happens. Thanks again I will keep everyone posted on how I make out.

 

[jtexas]

Re: Fish finder

do you guys ever see series of diagonal lines on your screen while anchored or drifting, kinda like this:<br /><br />

<br />with a slight curve, top to bottom, over an area you know is completely clear of obstructions? Somebody told me once those are bubbles, but that was just a theory - could be true - like if there's rotting vegetation or sunken log or a dead body or something that gets disturbed by a lure or wind current or something could release bubbles - or a giant sea turtle in the middle of the lake - but I'm not convinced. I've seen 'em in the middle of the summer and in the fall.

 

[waterinthefuel]

Re: Fish finder

On my Garmin 240 blue I can see fish arches very easily. I simply turn it on, the auto setting is good enough to start showing arches when the boat reaches a certain speed. I was amazed to see arches, I think sonar is a wonder of God.

 

[jch7450]

Re: Fish finder

Jtexas I'v owned a many finders, never saw lines like that. You werent in lockness were you? You have found the lockness monster...just kidding