Dragonfly 7" fish about 20 inches long from sonar image?

[ray18]

Dragonfly 7" fish about 20 inches long from sonar image?

I captured this fish lying on the lake bottom of 8 feet deep with my dragonfly 7 chirp fishfinder. I zoomed into water column between 4 feet and 8 feet. The fish is taking about 25% of the screen. I know my sonar covers 5 feet diameter circle cone for every 3 feet of water.

Am I correct about my calculation of the fish size?

25%*(8-4)*5/3=1.67 feet or 20 inches?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Ray18,

Please click here to view the response to your prior thread regarding interpretation of sonar images.