Depthfinder moron (Garmin 498)

[Kayak fisherman]

Can you guys help me out? I have a Garmin 498 chartplotter and the depthfinder/fishfinder (at default settings) seems to work fine in the rivers and the bay, but I can't seem to set it correctly in the ocean. It never really seems to be able to see anything except for the ocean floor. I've been thru the manual, but it doesn't help me.

My main questions are regarding the settings for GAIN and WHITELINE.

Maybe the reason I never mark any fish is because they're just not there. But it seems like I should occasionally mark something.

[Kayak fisherman]

Nobody else has a 498?!

[1987-cobb]

try this forum. Lots of Garmin users here. you will need to register.
Boating & Fishing Forum - Marine Electronics Forum

I would think if you are seeing the bottom and nothing in between, then there is
nothing to see. The ocean is mostly empty. I have not used a Garmin in four years,
so I really can't speak for them.

[Roger T]

Also keep in mind even with the proper settings your unit may not always pick up fish .