in-hull transducer help

[uc4me]

Does anyone have experience and/or performance notes with mounting an IN-HULL transducer?  (I've looked trough the strings and could only find info on the 'transom mount' and the 'through-hull' option - sorry if i missed it).

I have a Humminbird 587ci Combo and may exchange the transom mount transducer that came with it for an in-hull.  Note: says it will only work with a single thickness hulled boat - should i assume my '72 19-6 is single thickness?  

I plan to place somewhere near the bilge pump on the flat bottom, but not too close.  I'll route the 2 wires up along the bilge pump hose outta the floor with one going to the helm and the other (temp wire) winding its way up and over the transom to the water line.  Thanks for the input!

Humminbird 587ci Combo and in-hull transducer links below.

http://tinyurl.com/22ux5du
http://tinyurl.com/238bxag

[DOCREED]

The shoot thru the hull transducer has the same "pill" that the transom mounter version does.  If you install it at a location that is solid glass, you should have similar performance as the transom mount.  You may lose the ability to get watertemp and it may not reach as deep, but for most people that is fine.  make sure there are no air bubbles between the ducer and the inside of the hull.

[seabob4]

Shoot-thru-the-hulls, as we call them, need to have a solid glass bottom, no coring.  Most builders don't use coring in the hull bottom, so you should be fine.  If the bilge area has a liner that is bonded to the hull, you can use an oversized hole saw to cut through the liner to get to the hull bottom, then install the ducer in that cutout...

[flounderpounder225]

When I bought the 245 Osprey in Savannah, and started tearing into it, one of the first things I wanted to get rid of was the shoot through ducer for a cheap bottom machine, so I could install my Raymarine unit.  Of course just reaching the hull was a challenge, but one of SeaBob's posts helped by instructing to remove the door frame assy. so I could jamb more of my big a#& in the hole. LOL.  Next I dreaded what the guy used to secure the ducer to the hull, 5200, 4200 etc... to my surprise, they had used plain clear silicone, apparently it worked well, it took a little effort to remove it, but nothing more than a good pull.  I think if I was going to do a shoot thru, I would clean the area extremely well with denatured alcohol, rough it up a little, clean it again, let it dry out good, then spread a nice fairly thick even coat of 100% clear silicone on the ducer and push it into place, spread the silicone out evenly making sure there are no air pockets.  
Marc

[bumpster]

Wouldnt it give better performance if it was embedded in some type of resin? Silicone wont degrade the signal? I have mine old school since I have speed and temp but silicone seems like it would "muffle" the return

[seabob4]

The key is to just put the bead of adhesive around the flange of the ducer.  That way the element only sees through the bottom of the hull.  Fill the body with mineral oil, will work like a charm...

This is the Airmar that is pretty standard throughout the electronics industry that offers a shoot-thru ducer option...

[uc4me]

ok, thanks all.  That gives me the green-light feeling i was looking for on the 'shoot-thru' ducer.  (instructions kept saying in-hull but i get it now).

Looks like the bottom is glass with no liner to me so if you feel its single structure - i'm gonna try it.  This camera shot is from sticking camera in the stern port hole facing toward the bow.

[John Jones]

I saved this from the Humminbird website years ago.  Apparently the link no longer works.

Inside the hull mounting generally produces good results in single thickness fiberglass-hulled boats. Humminbird cannot guarantee depth performance when transmitting and receiving through the hull of the boat since some signal loss occurs. The amount of loss depends on hull construction and thickness, and the installation. This installation requires slow-cure two-part epoxy. Do not use silicone or any other soft adhesive to install the transducer, as this material reduces the sensitivity of the unit. Five minute epoxy has a tendency to cure before all the air bubbles can be purged.

http://www.humminbird.com/hb_MoreSupport.asp?id=147

My transom mount puck is just sitting in the bilge and works fine but I have not been deeper than 90'.  There is always a 1/4" inch or so of water in there to make it work.

[John Jones]

Here is the current file for in-hull installation.  They still recommend slo-cure epoxy.

http://www.humminbird.com/pdf/transduce ... deHull.pdf

[slvrlng]

Kevin, make sure those areas in your pic  that are on each side of the keel bottom aren't balsa stiffeners. I know I have seen them on quite a few rebuilds. They are usually rectangular and after 30 years they are also mulch. If you place the ducer on them it will have an effect.
Here are some pics of Mad Dogs 22-2 from bateau2. This is how he replaced his. Thanks MD!

http://forums.bateau2.com/viewtopic.php ... &start=100