Getting blobs rather than arches on fishfinder

[ballyhoo]

Installed a garmin 240 with the transom transducer. Reads bottom great, occasionally looses bottom at higher speeds. My big gripe is all marks within the water column appear as blobs rather than arches. Has anyone else had this problem, or know a fix.

[Cooper]

I don't think that's really a flaw. I have a 1000w simrad unit that display blobs when I come across a school of fish. I think it's a more accurate display that way.


pig dog toad
images

[auguste]

Its scary replying after Cooper as you never know when a shark will appear !

I've had four different fishfinders to date and only larger fish, probably more than 10 lbs., appear as arches, and the amount of arch seems to depend on how you have set up sensitivity, scroll speed and a couple of other factors.

Cooper is right, schools of bait fish appear as a cloud . . . however on a couple of occassions I have seen schools of bait fish so dense that it appeared as a second bottom on the screen . . . truly impresive

Hope this helps

[ballyhoo]

Thanks guys, for laying my fears to rest. I was worried that because I was not getting the pretty arches they show on the demo mode I may have someting set up wrong. But this past weekend I marked fish and was catching them where I marked them, guess that is all that matters. Thanks again

[Lead_Head]

Also look for "blobs" in cases where your boat is in rough water or swells. They would likely be nice clean arches on slick water. MY experience says "blobs" are vertically smeared arches.

[Harry Brosofsky]

My L760 did the same thing before I had the software updated. Now they look like blobs with very thin arch "tails" on either side. I have a slight dent on my Airmar transducer, but I don't think this affected the inner workings.

Later,

Harry

[Mumblerone]

ballyhoo ... I'm not familiar with the Garmin 240, but a quality FF should show arches. I would give Garmin a call and discuss. Did you get a video with the unit that showed arches or just literature. Low end units (because of pixel size) typically show blobs or various size fish likenesses...all swimming the same way with the exact depth on their back! Arches are important; they tell alot.

Boston Whaler, "MUMBLER", 24' Outrage, twin 175 HP Evinrude Ocean Pros. Snowball, the cat...

[Tom Keels]

We have the 240 and it does show arches on bigger fish. We have actually been able to countdown to strikes when trolling for grouper. However, I would not expect anything to look like the demo mode.

When bottom fishing we can usually pick out rocks and coral, and there will be blobs around, but those are generally small fish and trash. I think the sonar beam has to hit the fish just right to get the arch to show up.

http://www.bigbendfishing.net

[Mumblerone]

An arch is nothing more than a mark on the recorder that get higher as you move closer to the fish (assume suspended); as you pass over the fish and get farther away, the mark goes deeper. The high point of the arch is right under the transducer. Arches are important. If the arch had unequal legs, this implies active fish. If the arches are near straight lines, very active. On a color machine you can actually see the 'air bladder' which helps identify the species. (I still cannot tell male from female, however. ) ARCHES are important, don't settle for less! A round large blob is usually a ball of bait fish...NOW when you can see unequal length arches in the ball...hold on!

Boston Whaler, "MUMBLER", 24' Outrage, twin 175 HP Evinrude Ocean Pros. Snowball, the cat...