Transducer question

[sailscubasurf]

I own a 1972 Santana 37 (cored hull) and am attempting to upgrade the chartplotter / sonar with a new Garmin 942.

The old owner (of 32 years), rather than drilling a hole in the hull (which I agree with), fabricated a waterproof box, which he filled with some kind of green fluid (still there) and placed the through-hull transducer in the box and sealed it up.

I assume it worked, but by the time I bought the boat, the display unit was bad and I removed it during my early fix her up phase.

Now I am wondering if I can do the same with a new Garmin through-hull transducer as I really don't want to put another hole in the boat.

I've attached a picture of the transducer for reference.

I would love to hear from anyone that has seen this setup or installed something like it on their own boat.

Gary Green

[CharlzO]

A lot of modern units can be affixed in similar manners. Usually the transducer is mounted to the inside of the hull in either epoxy, plumbers wax, or some even have purpose-built rings that would be filled with something (RV antifreeze for example). This only works on solid glass and not cored hulls, but it sounds like yours is already proven to work. Depending on the box, you could probably reuse that, or you can use one of the other mounting variations. Do a search for shoot through the hull transducers, and you'll find plenty of examples and suggestions.

[billknny]

Originally Posted by CharlzO

A lot of modern units can be affixed in similar manners. Usually the transducer is mounted to the inside of the hull in either epoxy, plumbers wax, or some even have purpose-built rings that would be filled with something (RV antifreeze for example). This only works on solid glass and not cored hulls, but it sounds like yours is already proven to work. Depending on the box, you could probably reuse that, or you can use one of the other mounting variations. Do a search for shoot through the hull transducers, and you'll find plenty of examples and suggestions.

Some transducers (Aimar P79, for example) are made specifically to shoot "though hull", but any can be retrofitted into a box like you describe.

It is possible that the PO removed the core under his transducer to allow it to work. Shooting though core would attenuate the signal dramatically. It MIGHT work, but I'd be surprised if it did through a balsa or foam core.

The fluid usually used is straight propylene glycol (non-toxic antifreeze).

[AKA-None]

Originally Posted by billknny

Some transducers (Aimar P79, for example) are made specifically to shoot "though hull", but any can be retrofitted into a box like you describe.



It is possible that the PO removed the core under his transducer to allow it to work. Shooting though core would attenuate the signal dramatically. It MIGHT work, but I'd be surprised if it did through a balsa or foam core.



The fluid usually used is straight propylene glycol (non-toxic antifreeze).

Agreed the po May have removed the inner skin and epoxied. You should be able to tell by looking at the inside surface. But you can simply try it as is to see if it works