I have a 10.5 foot semax inflatable boat...... mainly used for diving I think. Has a 1.5 inch transom and can hold up to a 15 hp outboard, though I am running a minn kota 55 lb thrust on it.

I am trying to figure out what is the best fish finder I could hook up to it. I am a little shy about drilling into the transom to mount a transducer. I have a 12v deep cycle battery for the motor which I figure could work for some of the non battery powered models out there.

Been looking for months..... really been batting around many options. Not afraid to spend a few buck for a quality unit, but do not think I need GPS or anything too crazy, as this will be my first fish finder. Been looking at the color garmin and some of the more standard ones (hummingbird, lowrance...ect) with a possible suction cup mount.

Thoughts???

included picture of boat.

   I used to fish out of an Achilles inflatable.  It's basically the exact same thing you pictured there.  A suction cup mount won't work.  It won't adhere securely to the surface of the boat.  What you can do is mount the transducer directly to the TM head.  Almost all sonar manufacturers make a bracket that will allow it to mount on the TM.  Usually it's just a bracket that has a couple of slots in it to allow a large hose clamp to pass through it and over the trolling motor.  The single 12v battery will be fine to power the motor and a sonar.  If you've got a halfway decent battery, you'll be able to run basically all day.

   There are literally hundreds of different choices of sonars.  Go to one of your local stores, play around with a few of them, and find one that you like.  Both Humminbird and Lowrance make quality products.  Eagle units are made by Lowrance.  They just don't come with all the extra bells and whistles of the Lowrance branded units.  Just remember, the higher the screen resolution the better.

Thanks ..... I was looking into that, but have heard that a mount on a motor, especially a TM, is not really an ideal set up....lot of vibration messing with the transducer. 

Have you heard of this?  Have you experienced it at all? 

I think that might be my best option though...

Millions of people across the world have a transducer on a trolling motor. ;D I think that speaks for itself.

I've got a transducer on mine and have no issues at all. The only thing you may have to worry about is electrical interference messing up the signal. I doubt you'll have that problem though. Most of the newer shielded cables do a good job at getting rid of it.

I fish out of a 9ft pontoon type boat and I use a portable Hummingbird fishing buddy you might take a look you could install the mount right on the transom and never have to worry just remove the fish finder when not in use.

I have looked at those a lot and seen they have the side scan feature....which looks interesting.  Do you actually twist the pole part of the fish finder around to scan or does it stay stationary the whole time?   

What model buddy do you use if you don't mind me asking, because those have been near the top of my list, the reviews are good on them. 

I have a Fishin' Buddy 120 on my Sevylor 12' inflatable and it works great. It twists around, but the Side Imaging is not really like the one on some higher end fish finders. It shows cartoony images of fish and gives you a reading in feet on how far away they are. I've never had any luck using it and turn it off while I'm fishing. It works great, but one word of caution: I use a 30lb motorguide TM on the back of my boat, and it pushes it around pretty fast, but the fishfinder starts to vibrate at top speed. I can only imagine with a smaller boat and a bigger motor like you have, that this effect if going to be much greater, so you may have to pull it up out of the water when moving, especially if you ever put an outboard on it.