Fitting a transom mount transducer inside.

[Trop Cher]

I'm thinking of fitting a fish finder to my boat and would like to fit the transducer internally. Now I've successfully done this before on a previous boat but that was with a through hull transducer, however most fish finders now seem to come with transom mount transducers. Question I'd like to ask is can you mount this type of transducer internally just as you would a through hull transducer?
Boat is GRP and the fish finder I'm considering is the Raymarine Dragonfly.

Thanks.

 

[NormanS]

I did just that, also with a Raymarine Plotter / Fishfinder. I just hacksawed off all the extraneous sticky-out bits, and stuck it inside. Works perfectly.

 

[Seajet]

I have a Garmin fishfinder, the transducer is the ' transom mount ' type but I stuck it with sealant directly to the inside of the grp hull, works very well.

 

[NormanS]

Maybe I should add that as the transducer should be mounted as vertically as possible, I used a wee bit of plastic drain pipe, cut at an angle to make a shuttering for the goo to bed the transducer onto.

 

[Norman_E]

I stuck one inside with Blu Tack and it worked! Sticking it with epoxy would be better. It will only work if the hull is solid GRP, not cored.

 

[Seajet]

Maybe I should add that as the transducer should be mounted as vertically as possible, I used a wee bit of plastic drain pipe, cut at an angle to make a shuttering for the goo to bed the transducer onto.

The Garmin transom transducer looks a bit lke a 3-pin electrical plug without the prongs; I just stuck it directly on the inside of the hull at the fairly flat aft section, behind the keel and just to one side to avoid any disturbance from the keel.

It's not absolutely flat when the boat is upright, maybe 5-10 degrees off, but the angle of the signal cone is easily wide enough to allow for that.

 

[Trop Cher]

Many thanks, that's what I was hoping to hear.
I think I'll go ahead and order the Dragonfly, seems like a good piece of kit.

 

[Trop Cher]

Maybe I should add that as the transducer should be mounted as vertically as possible, I used a wee bit of plastic drain pipe, cut at an angle to make a shuttering for the goo to bed the transducer onto.

Thanks, I'll probably try something similar.

 

[John the kiwi]

I bedded mine on a wad of vaseline - just to see if it would work. I intended to bed it in epoxy but 3 years later it is still in the vaseline and still working.
I built a small box to surround it and protect it from accidental knocks. The transducer hasn't moved at all but using vaseline instead of sealant or epoxy i could easily get it out if i needed to replace it.

 

[single]

I checked the position was suitable by putting the transducer in a bag of water like a goldfish! When i got a good return i mounted the transducer in a bed of sealant in that position.Works perfectly.

 

[salar]

Many thanks, that's what I was hoping to hear.
I think I'll go ahead and order the Dragonfly, seems like a good piece of kit.

Hang on - the Dragonfly uses a Downview transducer which is not the same as the ones that the other posters have been describing. I would recommend you check with other owners before investing, or be prepared to hang it on the transom after all. Standard transducers can be mounted inside the hull in a variety of ways.

 

[single]

Hang on - the Dragonfly uses a Downview transducer which is not the same as the ones that the other posters have been describing. I would recommend you check with other owners before investing, or be prepared to hang it on the transom after all. Standard transducers can be mounted inside the hull in a variety of ways.

Mine is a downscan type and works fine through a very thick hull.

 

[stuartwineberg]

Hang on - the Dragonfly uses a Downview transducer which is not the same as the ones that the other posters have been describing. I would recommend you check with other owners before investing, or be prepared to hang it on the transom after all. Standard transducers can be mounted inside the hull in a variety of ways.

+1 I am pretty sure the Dragonfly is very different to the normal transducers that can be fitted as described by other posters. This was my main driver for purchasing a conventional fishfinder. I would be interested to know if it does work in hull though

 

[oldsalt]

if you want to see the depth when sailing at a high angle.
You can hang it so it swings as the angle changes, this also means it has to 'in' an oil bath, so a small cotainer with the bottom cut out and stuck down works well.
Good luck and fair winds.

 

[Spirit of Glenans]

In my first boat, a Leisure 17, I was only aware of the oil-bath method of using a transom transducer. I cut a piece of 4" sewage pipe to shape so that it would sit vertically in the centre of the bilge and glassed it in. I then made a small bracket to mount the transducer on the underside of a large cork stopper from a kitchen storage jar. I used a half litre of castor oil, (doesn't go rancid) to fill the pipe enough to cover the bottom of the transducer. Fearful of the cork falling out, I drove a dowel through it and made corresponding cuts in the top circumference of the pipe, in the manner of a bayonet light fitting. Worked perfectly!

 

[C08]

Be careful in your choice of adhesive to stick down your transducer. Anything BUT epoxy. I used epoxy once and when I came to remove it a good chunk of the hull came with it and needed repair for piece of mind, rather than leave a weak spot.

 

[stuartwineberg]

clear cheap bathroom silicone is a good one - plenty of time to get the transducer level before it sets and easy to remove if necessary. Thick enough not to go everywhere (as mentioned I built a small well out of cardboard and stuck it to the hull with blutack. The only important things are to make sure there are no bubbles or it wont work and make sure the hull isn't cored - only works with a solid hull.