Transducer R&R

[Gulf Comanche]

Greetings all:
My 23 year old depth finder died and I am working on replacing it. The biggest issue is that the boat needs to be hauled in order to change out the transducer. I have attached 2 photos to better explain. On the outside of the boat, below the forward jack stand, you can see a small vertical sleeve sticking down. The other photo is inside the boat and you can see the top of the vertical sleeve and top of transducer with the wire coming out which is 2 inches in diameter. My question here regards "marine sealant". Instructions call for the use of marine sealant on the base of the transducer where it slides into the sleeve. While the boat is hauled it will be pressure washed and I'll install the transducer; the boat is then put back in the water when washing is finished. Every sealant I've researched, excepting butyl tape, has a minimum cure time of 24 hours and I can't wait that long. I've thought about having a gasket made to fit the transducer base but want y'alls opinion on how to handle this issue. Thanks in advance,
Mike

 

[ranger58sb]

Hmmm... interesting...

FWIW, neither of ours call for a sealant, and both can be pulled while in the water (temporarily replaced by a "blanking plug"). Takes a bit of intestinal fortitude to pull one of them, since that one lets in a bit of a gush...

-Chris

 

[ghost]

If I remember right, polysulfide cures underwater. Have you looked at lifecalk, I believe they are the last ones producing a polysulfide, now in a world with no 3m 101.

 

[Gulf Comanche]

Chris: The one I've ordered from Airmar is the same, the shell is what is placed in the metal sleeve on the boat and then and then tightened up with a nut on top, inside the boat. The transducer itself slides into the shell and is watertight due to O-rings on top and bottom of the transducer. The shell itself has some sort of "valve" that slows or stops water ingress when you pull the transducer out. Then you put the "blanking plug" in the shell until ready to re-install the transducer.

 

[Gulf Comanche]

Ghost: it works in the water but needs 24 hrs to cure before going in the water.

 

[Cigatoo]

Most transducers come with a sleeve that is bedded into the hull and then the actual transducer slides into the sleeve using a couple of rubber o rings to seal. If you are replacing with the same type, the new transducer should fit into the existing sleeve. No sealant will be needed and you don't have to haul the boat.
Sorry if I missed something in your question.

 

[Gulf Comanche]

Easting: To the best of my knowledge there is no sleeve there now. There might be but the only way to find out is to remove the old one (see picture in 1st post). That could possibly result in big water inflow. Need to haul the boat anyway to pressure wash the bottom. Thanks.

 

[ghost]

Q Must I wait for LIFE-CALK to completely cure before I can put my boat in the water?
A No, LIFE-CALK will cure under water even though painted over.

 

[psneeld]

I have to disagree with most transducers are water removable because they are in a sleeve.


The older 3 function Airmars (made for most companies) only had the water speed paddlewheel removable. Depth and temp remained in the overall housing.


Some new function ones such as side/fwd sonar might be plugs as I am not familiar but someone just recently posted.


However, the vast majority of ducers are not plugs....many now are shoot through the hull where it is moot.

 

[koliver]

I have to wonder why you are going to all that trouble. Is yours a wooden hull, steel or aluminum? If GRP, then a shoot through the hull installation of the new TD is so much easier and effective for all but 1000 ft depths.

On a metal or wood hull, a transom mount is available for most sounders and presents a much easier installation.

I have 2 "old style" transducers hanging below my GRP hull, that have been redundant for years, since the obsolete sounders they were mated to were replaced by units with inside TDs. I have never missed the accuracy at 1000s of feet, or the water wheel speed sensor that would fail long before every haulout, due to barnacles or other growth.

They also present a significant challenge to remove, so I just ignore them.

 

[DavidM]

Lifecaulk, 3M 4200, etc. will all seal water fine if you give it about an hour to skin over and will cure in place underwater.

David

 

[Gulf Comanche]

Aluminum hull so I'm going with an Airmar transducer that will work with the Raymarine i40 depth sounder. West Marine in Mandeville LA were very helpful and I ordered the unit without the transducer that comes with the package because it was too short to fit where it goes in the boat. Airmar was also great to work with and sold me a td that will fit. Thanks for all the suggestions for sealant, looks like Life Caulk will work.
Mike