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I have been using two transom mount transducers on Razorsharp since I bought her and i am sick of cleaning, adjusting, and generally being dissatisfied with the function of these units. I am going to either do shoot through or through hull and am looking for some input as to whats best and install tips. Best spot, how to prepare the glass below, proper installation etc...

Thoughts?

Mark, I had Garmin sounder with an Airmar P-79 "shoot through hull" transducer that would mount on a hull with up to 22 degrees of deadrise. It worked flawlessly. Although the B-31 has almost 24 degrees of deadrise at the stern, it is not as steep forward, so the Airmar worked great. It was adhered to the bilge under the cabin deck (with epoxy or 4200) about 5" from centerline and filled with something like linseed oil. Most of the electronics companies use Airmar transducers, so do a search and it should pop up. I highly recommend it.

I had the standard airman B744 thru hull on a high speed fairing block and it worked ok. I'd loose bottom at 300' at cruising speed and I would get all kinds of funky returns on the screen. I decided to make the hull transducer cavity in Capt Pat building tips section. OMG, what a difference at cruise speed I'm reading well into 1000'+ at trolling speed 2000' and no more funky returns.

My previous B31 had a bronze through hull mounted under the starboard motor just outside that motor mount/stringer. It read great and I never lost bottom, though I boat in relatively shallow water. My current B31has an Airmar 260 shoot thru the hull mounted in the bilge forward just aft of the bulkhead between the v-berth and salon. It also works great. My B20 has a smaller hockey puck type shoot thru, mounted in the bilge near the transom--works great. The B20 is only one I picked the location for rather than a previous owner. I couldn't get the transom mount that had been on the B20 to read well. Electronics guy thought it was hard to do because of the strakes on the narrow B20 hull. Had a friend run my B20 while I laid by the bilge and slid the shoot thru around until I found the best spot, and its works great.

If you do a shoot thru, I found that mineral oil and 4200 or 5200 don't mix. It'll take a few seasons, but mineral oil degrades 4200/5200 and it'll leak out. 4200/5200 use anti-freeze, epoxy and you can use mineral oil

I put the Airmar 164 in mine. If you can get over the 4 inch hole you have to make, you will find that it works really well.