Mad Frog Liberator/Scotty vs. Ram

[habanero]

Originally Posted by Iceman

Using the RAM wedge mount in the sail mast will have you drilling no holes. Transducer over the side/ inside there are trade offs. You do get more detail especially at greater depth going over the side, snagging debris is an annoyance.

Iceman has great points and the RAM wedge deal is the answer. I've had my share of outbacks and have been around the block with mounting stuff. Less is better. The more crap you have hanging over the side, the more chance you have for things hanging up when it counts.
Dragging a transducer will get annoying trying to hear surface disturbances. If you have a weak transducer (low power = lower cost) Through hull mount might make a significant difference. My power output is 250 Watt (RMS) / 2000 Watt (Peak-to-Peak) and I didn't notice any significant performance hit mounting inside or out. BTW my Humminbird claims an 800' max but in murky salt water, I'm lucky to see past 400'. (The good news is, I never fish 400' down) I'm not sure how a 160c does in salt water but I think size does count when you are talking about transducers.
I have a revolution now and I can simply run connections from the head, (mounted at the mast hole with the ram wedge) under the front hatch lid. The revolution has such a high lip that water can't get in once secured. I don't think the 2010 Outback has the same design so you might opt to drill a hole. The transducer sits in a foam holder that I fill with water every time I fish. I was never happy with several attempts using the various glues. Trapped air bubbles will jack up your signal and this is no problem when you use water.
I'd like to take credit for such elegant solutions but these ideas come from other, far more experienced kayak fishermen.

Your biggest foe will be salt water getting into you connections. Di-electric grease the hell out of your connections and make as little connection outside the hull as you can.