I am constantly amazed by the accuracy and clarity of the Raymarine CHIRP DownVision combined with the C-MAP charts. Here’s a perfect example, when I’m fishing the Gulf of Mexico targeting nice grouper I need to find what we locally call “Swiss-cheese”. This is referencing structure along the limestone bottom that has holes and crevises instead of structure that comes up from the bottom.
Look closely at the above image and you will notice small structure outcrops off the bottom but most importantly the descending layers on the bottom that is clearly marked like a photograph by the Raymarine CHIRP DownVision. My fishing buddies in Florida use other fish finders and they don’t see the “cheese”, that gives me a big advantage!!
These areas are “jackpots” for larger grouper. When we locate these areas we drift over them with large cut baitfish and as soon as a grouper takes the bait our only goal is to stop it from going into the “Swiss-cheese”. If you can keep the grouper off the bottom for the first :30 sec, you can usually get it to the boat. If not, usually broken line and re-rigging!