Has anyone set a depth transducer (without a thru-hull) in this stuff or "your suggestions"?

kapnkd

kapnkd
Not so sure how that would work?

...The need for a transducer to work relies on there being NO air or air bubbles between the transducer and reading the bottom. MOST foams create bubbles as they expand and grow. Our ‘73 Ericson hull was well laid up with no bubbles in the hull glass.

Early on when I bought my Ericson, I glassed a large vertical PVC tube to the inner hull, filled it with mineral oil and placed the transducer into it with a clear piece of plexiglass on top to monitor the mineral oil height in case of a leak.

The readings on my then Pierce Simpson analogue depth finder worked great for years and years. The mineral oil was thicker than water and never leaked out.

We now use a multi-system of digital speed and depth using a thru hull sensor that hasn’t leaked a drop either.

We DO keep wooden plugs at the ready for all thru hulls as a precaution. (IF you have it, most likely there’s less chances you will need it!)
 

1911tex

Member III
Thank you Kpnkd! I also read that folks on this forum used a heavy dose of silicone to set the transducer against the hull...first putting the transducer in a bag of water as a test to make sure the location was acceptable. Just curious about this closed cell polyurethane foam.
 

kapnkd

kapnkd
Thank you Kpnkd! I also read that folks on this forum used a heavy dose of silicone to set the transducer against the hull...first putting the transducer in a bag of water as a test to make sure the location was acceptable. Just curious about this closed cell polyurethane foam.
Sorry I don’t know more about the total density of the closed cell foam. All I know is it doesn’t absorb water.

As for sealants. We prefer to use either 3M’s 5200, 4200 or Boat Life Caulk.

Word of caution - IF you will ever want/need to remove whatever it is - the 5200 is VERY hard to undo!!!
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Remember that when sealing the transducer against the inside of the hull you must avoid any (tiny) air bubbles in the bonding medium. If using epoxy resin, even a stirred-in bubble will reduce the passage of sound signal. So, if you use a "foam" product that always has air entrapped in it, it will likely halt sound waves or severely reduce them.
I have successfully bedded an inside transducer with solid sealant, and the head of the transducer was also tight against the hull surface.
 

1911tex

Member III
Remember that when sealing the transducer against the inside of the hull you must avoid any (tiny) air bubbles in the bonding medium. If using epoxy resin, even a stirred-in bubble will reduce the passage of sound signal. So, if you use a "foam" product that always has air entrapped in it, it will likely halt sound waves or severely reduce them.
I have successfully bedded an inside transducer with solid sealant, and the head of the transducer was also tight against the hull surface.
Loren: Do you remember what solid sealant you used? Thanks!
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
That was on our prior boat, in the 80's. I am sure it was a common polyurethane combination adhesive/sealant. Nowadays I usually use BoatLife "Life Seal".
Only product I stay away from is 5200. :(
 
Top