# tweaking sonar to mark at speed



## boss302 (Jun 24, 2005)

I need some help tweaking our sonar unit to mark fish at a reasonable speed. Perhaps it does and I'm just not interpreting properly? We have a Lowrance 520 series color sonar/gps combo unit with transom mounted transducer (I forget the model number whichever one has the internal gps antena). No problems marking bottom, but don't see fish unless we stop the boat and get down to less than a few miles per hour. Is there some setting that would help this? Will gladly try almost any advice. I keep seeing people mention being able to see fish at 20+ or even 30+ MPH, I'd be glad to see them at 10 and quite thrilled to do it in the upper teens - low 20s

bost is a Trophy Walkaround with I/O (model 2052).


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## K gonefishin (May 4, 2004)

You probably are marking them, you will just see them differently at higher speeds, the slower you go the looooonger the marks will appear (ice fishing with a lowrance they are flat lines if they aren't moving) spinner speeds they are long hooks, fast trolling speed they are shorter hooks. Up on plane they are vertical lines. Set your ping speed at 100% and chart speed around 90%

http://www.hightechfishing.com/highspeed.html Read all this info it will help you as well.


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## KaGee (Sep 8, 2006)

Cavitation, angle of the transducer, Electrical interference can all cause problems at higher speeds. I always slow down to look for marks.


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## K gonefishin (May 4, 2004)

Since you have a glass boat you really should buy a shoot thru hull transducer it will provide the clearest picture at all speeds, even if not if it's mounted properly you should have no problem marking fish with your boat. 

Aluminum boats have MANY more problems due to rivets, welds and lift strakes on their hulls, this causes air bubbles and other captivation issues to get into the way of the surface of the transducers face. 

Me personally I don't know what I would do if I couldn't mark fish at 20-35mph. One guy told me I was full of **** that I could mark fish at high speeds next time I'm out and in "search mode" I'm going to take some pics of my screen it's awesome being able to mark on plane...eliminating dead water is key to maximizing fishing time and spend more time in front of fish rather than looking for them. Expecially after a blow or fishing new water or when you don't know where the bite could be. When I fish offshore in Cleveland I may have to cover 10-15 miles or more before I run into a school of fish..without being able to mark on plane I wouldn't even bother I would go fish the sandbar and look for a pack of charter boats LOL


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## Hetfieldinn (May 17, 2004)

The boat I got last season is the first boat I've had with a shoot thru transducer. I'll most likely never mount a ducer on the transom again. I easily mark fish at 30+ mph.

If I were you, I'd first see what software your unit has, and update it if you don't have the most recent software, then I would seriously consider mounting the ducer inside the hull.


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## Whaler (Nov 16, 2004)

Try adjusting the angle of the transducer .


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## boss302 (Jun 24, 2005)

Thanks! I'll start with the simple stuff (chart & ping speed, firmware version check, transducer angle....) Hopefully that's all it will take as I'd rather buy a decent map card than another transducer.


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## boss302 (Jun 24, 2005)

I think I've got it. Just wasn't seeing the black specks as fish and not noise. 

I Did some playing around last week on vacation, whenever the black specks got thick, the fish were stacked.......black specks light, = scattered fish when we slowed down.

Thanks All!


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## COmmodore 64 (Jun 24, 2006)

Boss302, I need to tweak my Humminbird as well. I have sensitivity at 18/20 and Chart SPeed maxed and I still don't see anything but dots.


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