Bought a Himminbird unit years ago, with a transom mounted transducer--don't want any more holes in the bottom of my boat. Has worked very well. Only thing that bothers it are barnacles and grassy crud, but it's accessable where I mounted it for easy cleaning.

Jeff

Doesn't bother it a bit.

Jeff

All of my transducers are mounted under the galley floor on the 32 sedan. It's ideal to mount them before any disturbance such as intakes, props etc.
Generally the units come by default with the transom mount transducer. I've never been a fan of transom mount. I just order the nylon through hull. If you use bronze make sure you use a nylon sleeve to keep it from touching the hull. And use plenty of bedding compound. Most people will recommend 3M 4200 but I tend to go with the stronger 5200 just in case the ducer gets knocked/broken loose, that 5200 will hold everything together. Also recommend a fairing block to keep the ducer pointing down. The hull deadrise can be measured w/ a protractor or one of those angle measuring things from the hardware store.
Be sure to goop the threads of the ducer before you tighten the nut if you go with a through hull.

-Karl

..."I believe that our hulls are 3/16", "

Correct. Transom mounted transducers (now htere's a mouthful!) have the distinct advantage of not opening a gigantic hole in the hull if smashed off! On tilting them downward and mounting slightly below the bottom of the boat, that is the recommended procedure.

Jeff

This is the supplier for Lowrance, Eagle and Sea products. If you need a transducer for any of these products which were popular back in the 80's and appeared on many Marinette's this is the place.
I think Hummingbird also falls into the slot of one of the companies mentioned above. I think its Eagle.
Some of the transducers have been discontinued unfortunately. Ebay is the next option.

http://www.lei-extras.com/store/default.asp

-Karl

Yooper! Sorry about cutting the cord for the ducer. Whatever brand it was I had never seen one like it before. It was a tiny, cheaply made thing that was Velcroed to the helm.

Karl,

No problem. You didn't know about this stuff when you cut the transducer cord. I first tried to get Airmar to tell me how to hook up another gauge so I didn't have to pry the old unit out of the hull. They basically told me I was out of luck without the model number info which is on tape labels near the gauge end of the wire. Most depth sounder and fish finder manufacturers all use transducers from Airmar. Airmar uses the same basic set of pickups but the connectors vary based on the needs of the gauge makers. The connector/transducer combination determines the model number and the family of gauges you can use. A model number / gauge cross reference is available on the Airmar site. I was kind of upset that there is limited standardization in the connections even though the transducers are mostly from one firm. Some of the gauges, like my new one, can pass the information along digitally to another gauge with a simple repeater wire. This is usually done with a "NMEA" standard making making mixing manufacturers easier. The other feature of my new transducer is the insertable feature. This will allow me to slip another transducer into the housing which is cemented to the hull without prying the whole unit out. I am very satisfied with my new depth sounder rig.

Transom mounts for xducers are great if you get them in the right place for your boat. If they are in a stream of bubbles, they will not register correctly or at all. A good model will tell you all that stuff in the installation manual. What's nice is that every mount I've seen give you room to make an up or down adjustment til you get it right.

I had bad luck with my transom mount on a fiberglass boat (stopped reading when I picked up speed) so I moved to a thru hull. In that boat, I was able to mount the thru-hull xducer in the bilge and shoot the sound waves right thru the hull. It was carefully bedded in ordinary silicone laid down slowly so no air bubbles formed. What you saw above in one post is that there is a possibility you could do that in our aluminum Marinettes. Airmar can guide you.

And if you do go thru-hull, I would urge not to use 5200 sealant. It is almost permanent. There is a solvent for it but I don't think every marine store carries it. 4200 will be fine for bedding - flexible and removable. It is used just to seal out water, not hold the thing in place. And if you use a metalfixture coming thru the hull, make the hole big enough so that the metal doesn't contact aluminum. We all know that is beddy, beddy bad!

I had my depth finder replaced a couple of years ago. I also added one so that I would have one at each station. Mine are mounted through the hull. I am very happy with their performance and they work very well at any speed. You will need a fairing block if mounted this way, but from what I have read this is the best way over a transom mount. I have had no problems with leaking whatsoever... the 5200 is the greatest invention known to man....

Thanks....good to be back....don't know where I went...just kinda checked out for the Winter I suppose....Spring is here..kind of..we will be back in the water soon..

Screws should be Stainless Steel for anything on the boat.

Roger