I fish out of a bass tracker pontoon for Whites and Hybrids. Have a hummingbird 460t transducer mounted to the rear of the center 1/4 pontoon. The monitor is at the center console so I can't tell when I am on or off fish from the trolling motor located at the front. Now before you start laughing at me or suggest I get a real boat I would like your advice on what brand/ model of FF I should add at the front. I don't want the FF to be worth more than my boat.
Thought I would check EBAY or on the TFF for a decent used unit. I am not sure about compatibility issues (interference) between two different units or where the front transD should be mounted. I love my boat

If the two units are on at the same time you may have interference problems, regardless of manufacturer.

You may also have interference problems with the trolling motor....depends on the age of the trolling motor and what you end up purchasing.

I don't see anything wrong with your fishfinder being worth more than the boat...the value of the fish finder is more important than the value of the boat. A boat gets you on the water, they all do that...some are a litle more comfortable, a little bigger, faster, whatever but they still all do the same things. Not so with the fishfinder.

Personally...I'd try to find a Lowrance 522....5 inch color screen, internal GPS, compatible with Navionics cards, built in lake maps with contour lines, excellent sonar performance.....Academy had them on clearance a while back for about $400...probably can find some on eBay for about that.

You could probably just get an inexpensive Eagle fishfinder for the TM - since you have the detail of the spot you're fishing on your main fishfinder, you just need to know depth & see how many fish marks are there for the TM.

Humminbird 718 ...... 16 Level grayscale, 320v X 320H 5" LCD display, DualBeam Plus, 2400 watts PTP power output. Around $200 Good buy.

Kevin, if you were to give a max dollar amount, it would narrow down the recommendations. If bottom tracking and depth is all you need with a color view, then an Eagle 350C is all you need

http://www.cabelas.com/cabelas/en/templa...&hasJS=true

If you want to spend more and get a better pixel count, than a Lowrance 510C or 522 (as someone else mentioned) or similar would be a good choice. If you have a trolling motor, than simply mount the transducer on the TM motor housing. Hope that heps, good luck to ya

If it says "Thru hull transducer" Can this still be mounted on a trolling motor housing?

Yes, this is what is called a puck style transducer. It is used for thru hull, because it is flat and is easier to keep air bubbles from forming when installed. BTW, any type of transducer can be used for thru hull, so long as it is installed correctly.

Eagle 320 less than 150 bucks.

I'd put the hummer on the front and get a 522 lowrance for the console. I dont know if your toon has a top or not. The top might affect the internal gps antenna on the 522. Might be better to get a 520 with a remote mounted antenna. After having GPS and a map showing depth contour lines to me it would seem like fishing blind without it. Not to mention setting waypoints on it and being able to go back to the same spots every time. Running it in split screen mode allows you to watch the map and the sonar at the same time on one screen. The regular color lowrance finders with gps are getting a little more reasonable now since the high definition models are the "New Thing".
Dont skimp on the tronics.