Best place to mount my transducer

Need help guys.
Just bought a Lowrance Elite 7 chirp with GPS, down imaging, and sonar. I'm needing advice on where to mount the transducer. I have a 1993 stratos 285 pro xl an if anybody knows this boat you have your flat part of your transom where the motor mounts to and then you have a drop down that has your aerator pump holes and then it drops down again and that's where your plug goes. I'm needing to know the correct location to mount the transducer cause I only wanna drill once. Thanks for any info and help on this it's much appreciated!

Anybody??

I don't have a transom similar to yours, but maybe posting some pics would help folks visualize where it should be? It also will help people describe where you should put it.

When I did mine, I actually attached a piece of Starboard to my transom first, that way I would only have to drill into the boat once. If I need to move the transducer I just drill a new hole in the starboard, not in my transom.

I had a 1991 285 Pro XL and still have a 1996 201 Pro XL. Both have exactly the same stern configuration as you describe for your 285 Pro. The lowest step (where the plug is) has a very short vertical rise, and part of that is a non-flat radius to the next step up. It's not enough space to attach a transducer bracket. That leaves 2 choices.

On the 201 Pro, I set up an HDS system primarily for down/side scan, which is only done at slow speeds. Therefore, I put those transducers at the bottom of the jackplate that happens to line up with the highest step. These get out of the water when on plane. Using that highest step (actual transom where the engine mounts) will mean no high speed reading. I have a different depthfinder for high speed operation. It has a transducer embedded in the hull to avoid the stern step issues.

It seems your best hope is to use the middle step (where the aerator intakes are located). I agree with the above about putting star board on the boat and then screw the bracket to that. Star board can be cut/tooled as easily as wood but is perfect for the application. I would have the star board flush with the bottom of the step and between strakes of the lower hull. Use as large a piece of star board as will fit. This will give the most options on relocating the bracket if needed.

Thx guys! Where would I be able to purchase star board? I only have one on my boat couldn't afford 2 at the moment. The installation guide says mount it to the right. But a buddy of mine that fishes all the time said mount it where the aerator holes are also. I just want different opinions that way I know which is better so I get get on the water!! Idk how to post pics on here so that's why I didn't post any

I picked up my Star Board at West Marine. You can probably find it cheaper online or from a materials/plastics retailer - but West Marine is fast and right down the road.

The biggest issue with mounting it is you want it to be unobstructed. From Flippin's post though you might have an issue keeping it on the water when on plane. Stepped transoms are a little more difficult than flat transoms like mine. Good luck, and post pictures once you get it on!