So once I can find time to get to doing a title transfer, my Dad’s boat will be mine.   We had to wait for the death certificate.  
Its just a 15’ Starcraft aluminum boat like a bass boat but not as fancy.   Carpeted floods and raised now and stern.  Probably 1985 vintage or so,
It hasn’t been on the water for I bet 15 years.  It is in decent shape all in all.
So beyond the motor, which is only a 10HP Mercury (there are some lakes in PA we used to fish a lot that only allowed up to 10HP), what is a good fish finder now?
Seems like mid and upper range have GPS.  Nice for storing locations I guess
I have an older hummingbird 3D.  But the resolution on the new sonars seems to be impressive
Also had a side scan of some sort I don’t recall, but it never worked well.   I bought all these years ago, as an upgrade to the one my Dad and uncle bought with the boat.   A Ray Jefferson I think. What a load of junk. Must’ve had a 1 degree sonar beam.  I think it only ever picked up one fish on the screen
Mostly where I’d fish it’s not going to be large water or that deep.   Especially not until I get at least a 25 HP motor for it.  It think the hull is placarded for up to 40?

Im a fan of humminbird.  I did just put a 9"  garmin on my little 15' aluminum though. If your thinking about SI, i would recommend doing no less than a 7".  I find myself using gps, sonar, and side imaging more than DI.

Humminbird Helix 5 G2 DI GPS or Helix 7 DI/SI G2 GPS will do everything you need including storing lake maps and autocharting your own maps.  
Lowrance and Garmin both have good products as well, I just have more experience with the helix models.

I'll chime in that any of the big companies are fine to go with. I have a lowrance reveal 9 tripleshot on my kayak and will agree that if you're using sidescan, a minimum of 7" will be preferred. Garmin, Lowrance, Humminbird, are all g2g.

I have the lowrance hook 7 triple shot on my kayak.  Anytime I get in water < 2.5 it basically locks up any depth reading and I'm forced to restart the unit.

Interesting. I have not run into that issue with the 9 on my PA, or the elite 4 on my BG2. The elite 4 had issues but it was related to me and getting the transducer into gnarly situations.
How do you have your transducer mounted?

Its on a 2019 Hobie Outback so its mounted on the retractable plate.