Transducer Upgrade For Through Hull / XAP 9 20

I have a Humminbird 345C fishfinder.  It uses a 200 and 80 kHz beam.  On my T13, the signal is superb as it is installed in the modified scupper.  The transducer is IN the water.  On my Hobie Adventure however, I am forced to shoot through hull.  I have been disappointed and frustrated with the (lack of) quality of return signal.  I have tried it all; water bath, goop, and that duct “putty” stuff.  I have moved the location around to different locations in the hull.  It all sucks.

While perusing Humminbird’s website, I came across a transducer designed for thick fiberglass powerboat hulls. Has anybody tried this?  Im hoping maybe this unit will improve the return signal while shooting through hull. Any thoughts? 

http://www.humminbird.com/Products/XAP-9-20/

This is a thru-hull mounting transducer that works well with kayak scuppers as the transducer is outside the kayak. It is a solid one piece unit that slips in from the bottom and then a locking nut from the top side keeps it in place.

The long cable can then be run into the hull using a cable clam or similar approach. This is the only downside, the need to run the cable into the inside of the kayak.

Ocean Kayaks and possible Old Town have one large scupper that is designed to accept this transducer. Cost is $130 but Humminbird will give you credit for the retail value of the original one and adds in a $15 shipping charge so net cost is $75.

This transducer only works with some models of Humminbird finders so best to check beforehand.

This is a thru-hull mounting transducer that works well with kayak scuppers as the transducer is outside the kayak. It is a solid one piece unit that slips in from the bottom and then a locking nut from the top side keeps it in place.

No its not. This transducer is designed to be glued to the inside of a fiberglass boat hull and shoot through the boat.  I already have the "scupper transducer" apparatus installed in my Ocean Kayak.  Works great; not my point.

I want to shoot through the hull of my Hobie more effectively.  This transducer might achieve that.   

Matt, I've used those round puck-style Humminbird transducers on 3 different occasions. All mounted in the hull using goop. And signal resolution seemed pretty good IMO. Not necessarily better than a transom-style transducer gooped inside the hull; but it worked pretty good. One of them even had a temp sensor connected to the puck with a 10ft cord...which I ran back thru the hull (onto the deck) and installed in a scupper hole using a rubber stopper. The only downside to those transducers is finding a large enough flat spot in the hull (not a big problem but something to consider bcuz you want it to be flush against the hull...no air bubbles etc).

This is a thru-hull mounting transducer that works well with kayak scuppers as the transducer is outside the kayak. It is a solid one piece unit that slips in from the bottom and then a locking nut from the top side keeps it in place.

No its not. This transducer is designed to be glued to the inside of a fiberglass boat hull and shoot through the boat.  I already have the "scupper transducer" apparatus installed in my Ocean Kayak.  Works great; not my point.

I want to shoot through the hull of my Hobie more effectively.  This transducer might achieve that.

I have one of the transducers mentioned by the OP and it is sitting on my desk. The Humminbird XTH 9 20 P and it most definitely does go up through the scupper and attaches as I stated in my post. Why not take a second and read the original post and think before typing something stupid. It really is not helpful in the least.

I am inquiring about part number XAP 9 20 as stated in the title as well as the link provided.  Sorry for the misunderstanding.

My XAP 9 20 through hull transducer arrived last week.  While opening the package I discovered that this model features a face with a slight angle designed for the angular keel of a power boat, when I actually need a flat faced transducer. I was however, able to find just the right spot on the edge of the kayak that would allow the angled transducer to face pretty much straight down.  I then made a “reservoir” out of silly putty (in my favorite two colors) and filled it up with .75” of silicone glue and mashed transducer in place and allowed it to dry with a heavy sand bag to apply pressure. It dried almost perfectly level.

Today I took the boat out and was able to try out the new transducer.  I must say that I am super pleased with the results!  The image is clear and sensitive. I was able to track a bait all the way down the bottom.  This never happen while shooting through hull using the stock transducer. 

I have seen yellow and red kayaks shooting through hull using stock transducers getting perfect signal. Makes me wonder is something in Hobie’s “Ivory Dune” color mixture is absorbing some acoustic signal. It does have a granular appearance.

Regardless, I highly recommend using a “shoot through hull” style transducer if you use a kayak that does not feature a modified scupper.  Just be sure to make sure you get the flat bottomed unit; for my 345C the part number XP 9 20.

 
Thanks for the followup Matt. I'll probably try a XAP 9 20 or XP 9 20 next time I need to mount a Humminbird TD inside the hull.