Hey all. I’m in the market for a new fish finder. I mainly fish for tuna down in So Cal. I’d love to hear some suggestions. I don’t have a price point or limit.
Oh Man, not having a limit on $$ for a fish finder must be really nice! Ha, Just kidding.
None the less there are a lot of great units out there that don't necessarily need to break the bank in order to give really outstanding performance. One of the easiest to use and most powerful units out there is the the Garmin echomap Ultra series. These are offered with preloaded maps for the US, a big, easy to use touch screen and Transducer. They can shoot down to 800' so the So Cal Tuna Trenches should be no problem, as well as the Kelp Patties off Dana Point.
Check it out
Start with measuring your dash to see how much space you have to install a unit or two. Map out your dash for: GPS/Sounder, VHF, engine gauges, stereo (if you want one), autopilot, and god only knows what else you want on the dash. Many owners opt for a multi-unit that can handle: GPS/Plotter, Sounder & Radar. There are advantages to dedicated units vs multiscreen. You may also want to have 2 smaller screens v 1 large screen.
Do it first on paper: https://www.boatingmag.com/building-new-helm-panel/
You should then study w/n you want a chirp vs conventional sounder. Read: https://www.westmarine.com/WestAdvisor/Understanding-CHIRP-Scanning-Sonar
Next you should educate yourself on side imaging. You are going to want to consider side view sounders. A SV sounder opens a new world in fish finding. https://outdoorempire.com/down-imaging-vs-side-imaging/
SoCal Tuna will be in deep water. You are going to want a 1000KW capable unit. Do not opt for the cheap stuff because it won't see deep enough for you. You will also want temp reporting. Minor changes in water temp can make all the difference in the world for finding bait. If you find the bait you find the fish. Remember that whatever you buy will also have to support a 1000KW+ transducer. You should study transducers now before venturing out. Your boat will make a difference. High speed vs low speed boats have different requirements. Hull design also will make a difference here. If you are not sure what to do, take a photo of the bottom of your boat. That will help the rep suggest what transducer is right for you. A bad, good vs great transducer is like the difference between lightning and the lightning bug on what you see on the screen. A poorly installed transducer is just like throwing money away if you buy a quality Sounder. See: https://www.airmar.com/productinfo.html?category=MT&name=Marine%20Transducers
All of the above costs money. All of it this adds complexity to your purchasing decision.
After you know: what size screen, how powerful, CHIRP or Traditional (go chirp), side view vs not, and the type of transducer you think you are going to need, go to your local WM store and start pushing buttons. For most Chartplotter/Sounders, the big issue is the interface. They all pretty much work the same, but there are subtle differences. Your WM rep should know the advantages of one manufacturer to another. As all units today are NMEA, you can mix and match manufactures if you want. If your local WM does not have the unit you are interested in, ask them where you can locate one. There are many, many units to chose from. You may also want a unit to interface with your computer, boat engines, and more.
If after your visit you are still unsure about what in particular you need or want, call the manufacturer's sales desks. They are there to help you. You will learn a ton from the manufacturer. There are tons of youtube video's too. Everyone has an opinion. Everyone has a favorite. That is why there are so many quality manufacturers offering well made electronics.
After all is said and done, you sound like you should have a pro install the unit. It will be money well spent. You will need equipment to measure if there is outside electrical interference, sufficient power, water proofing the dash, grounding, proper fuses/wiring, and the biggest item: the transducer placement and installation.
Hope this helps you. Have fun.