Questions on Thru Hull transducer mounts

I just got a new Lowrance Elite 5x HDI unit in the mail today.  Thanks Jerry that Cabellas deal was too good to pass up ($199)!  Now for my problem.  My old unit (Lowrance X91) had a much smaller transducer that fit nicely up into the scupper hole of my Jackson Cruise.  I was able to tuck it out of harms way without a problem.  The new unit has a much larger transducer making the scupper mount not an option.  That leaves me with through the hull or over the side.  I would go over the side, but I like getting to the water and having less stuff to set up.

Down to through the hull.  I've researched most all the methods in the past, water bath, electric putty and all kinds of goops and goos.  My main concerns with them are loss of sensitivity and accurate water temp readings.  I would like to come up with a water bath solution, but in-hull access is not the best on the cruise.  That being said I've got a few questions for you guys.

1) How much loss of sensitivity do you see when mounted through the hull?
2) How accurate are the temp readings if you're not doing a water bath at the time of launch?
3) Do any of you have experience with this specific unit?  What do you think of it?

Thanks
2)
2)

1) The sensitivity loss on thru hull installation is minimal, if any. You won't notice a difference. I have the Elite 4 HDI and did a scuppered mount but I treat it with kids gloves. I know that they're meant to take some pretty good abuse, but I'm careful launching and always bail with a few feet to spare when landing to keep it away from rocks or the ramp.

2) Water bath or not, the temp reading will not be accurate in my experience on a thru hull installation. I find that as the day goes on, inside the hull warms significantly in the sun causing the temp sensor to read high.

3) I have the Elite 4 and love it. Yours has the same sonar features on a larger screen but no GPS. So many ways to customize the screens and views and really tailor the readout to whatever style of fishing you are doing. The ability to overlay sonar and DSI on one screen is great and the TrackBack is an awesome feature. Really a nice unit and I'm very happy with mine.

He beat me to all the good answers!   

I'm not a Lowrance or Jackson guy, but all that was good info.

I'm not a Lowrance or Jackson guy, but all that was good info.

Lol. We won't hold that against you Rob.  Lo . You're a Shasta Guy!

Still undecided on what I'm doing too.

Hate to add to the goop list, but I used a product called Geocell to glue carved styrofoam inside my hull for a water bath type install. It's held up great since '09.

On the temp note; sometimes exact numbers aren't really as important as simply watching temp change. If you need numbers dead on use the offset function after checking true temp with a thermometer.

My main complaint about using a water bath method...is all the water that gets into my hull. Normally this doesn't bother me, but when I'm going to a freshwater lake/river with mussel inspex...I spend a lot of time drying the interior with towels then fretting about failing the inspection the night before!
Plus, the water creates a cycle of condensation inside the hull...which is exacerbated if you have pool noodles! I have to remove my pool noodles if I plan to go through an inspection. 

I just got a new Lowrance Elite 5x HDI unit in the mail today.  Thanks Jerry that Cabellas deal was too good to pass up ($199)!  Now for my problem.  My old unit (Lowrance X91) had a much smaller transducer that fit nicely up into the scupper hole of my Jackson Cruise.  I was able to tuck it out of harms way without a problem.  The new unit has a much larger transducer making the scupper mount not an option.  That leaves me with through the hull or over the side.  I would go over the side, but I like getting to the water and having less stuff to set up.

Down to through the hull.  I've researched most all the methods in the past, water bath, electric putty and all kinds of goops and goos.  My main concerns with them are loss of sensitivity and accurate water temp readings.  I would like to come up with a water bath solution, but in-hull access is not the best on the cruise.  That being said I've got a few questions for you guys.

1) How much loss of sensitivity do you see when mounted through the hull?
2) How accurate are the temp readings if you're not doing a water bath at the time of launch?
3) Do any of you have experience with this specific unit?  What do you think of it?

Thanks
2)
2)

On the goop team too. Marine grade goop. No Styrofoam, just hopped to the hull. I have found that when ocean fishing, the temp starts a few degrees off (assuming an early morning launch when the kayak has spent the night on the coast) and usually adjusts to be a degree off.

Aloha,

Isao

Hate to add to the goop list, but I used a product called Geocell to glue carved styrofoam inside my hull for a water bath type install. It's held up great since '09.

On the temp note; sometimes exact numbers aren't really as important as simply watching temp change. If you need numbers dead on use the offset function after checking true temp with a thermometer.

Nice unit.

I'll cast my vote against GOOP. It worked great for a few months, then started to crap out (bad, inaccurate, erratic depth readings). When I pulled it off to see what was wrong, I found that many bubbles had formed in the Goop as it set. The bubbles weren't there when I installed it...

I now use a putty-like material called Duct Seal to make a water bath for my transducer. Haven't had a single issue since.

Thanks for the input everyone.  I decided to go with the water bath method after all.  Since accessibility is an issue, I mounted the transducer inside a waterproof box.  The plan is to cut the bottom of the box out, goop that down, fill with water and close the lid.  I will probably add some duct seal around the outside of the box to ensure that the water doesn't leak out.  I will post some pics when I'm finished. 

Closed cell foam works good too.

One more question. If I am able to suspend the transducer above a v-shaped section of the hull in a water bath will I get a clean signal? I know you are supposed to find a level spot but I am having problems finding one I like. The only spot that makes sense is way up towards the front where the hull is still pretty v-shaped.

I mounted the transducer level in a box and am going to build a well of duct seal around the box to hold the water in.

Ideally you want the transducer near the center of the yak. If it's up near the front, it will lose it's signal every time a wave rolls by and the nose comes out of the water. This gets very annoying, especially if your trolling in rough water.

As for the hull shape, I don't think it'll make much difference. The plastic doesn't really block or distort the signal. I think it's more a matter of making sure the transducer is oriented correctly and not firing at an odd angle (giving inaccurate depth readings).