Bonding Sonar Transducer to inside of hull

[Peters Wet]

So mounting is pretty straightforward, transmission through fiberglass isnt a problem but Im more concerned with signal properties, Has anyone ever seen or done an AB comparison between a thru hull an in hull installation?

[wolfesmy]

not that I know of but my signals have always been satisfactory with a hull bonding solution.

[a64pilot]

Last boat I had was for diving, and I used the Garmin 740S for finding dive sites, wrecks etc. I used the cup that you fill with anti-freeze and it worked outstanding shooting through the hull.
Later I put a Raymarine Drangonfly in as a backup, it's a CHIRP transducer of course and I believe it has to be transom mounted, but at least for a non CHIRP, shooting thru the hull works really well, good for telling bottom conditions and finding fish, but if your really after detail nothing beats a CHIRP.
BTW with a CHIRP you'll never see pictures like you see in the brochures, unless you in glass smooth water, reason is the vertical movement of the boat shows up in the picture, so an I beam on a bridge span for instance looks like a zig zag.


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[CarinaPDX]

What are the specs for the depth sounder in question? Few go beyond a few hundred feet. As I said before I was reading in excess of 500 feet and at times much deeper; it is really a matter of thermoclines and other conditions in the water that limited the performance. (Mine was rated at 600ft, and IIRC I got close to 1000ft at one point - but that is exceedingly rare due to conditions.) I don't see that those depths matter anymore, unless perhaps you are a fisherman and have a fish finder. A digital depth sounder shooting through the hull will be more than adequate - just check with KY first to avoid any voids in the layup (not likely, but still worth checking).

Greg

[Nanamuk]

After finding the area which will work as others have discussed I epoxied a short piece of PVC pipe large enough to hold the transducer to the hull (needs to be leak proof joint). I then melt Vaseline, put the whole jar in a pot with a couple of inches of water and heat on the stove till it is all liquid. Pour the Vaseline into the PVC, insert the transducer making sure there are are no air bubbles under it and support it horizontally until the Vaseline hardens. Very easy to change to new transducers when changing instruments and have read 900ft with my 25 year old Lowrance!

[Reefmagnet]

Use a wet zip lock bag filled with water to use as a medium for testing the position of the transducer. Even a solid hull may have a void which will upset the depth sounder.

Use a low strength polyurethane sealant to glue it to the hull, you can apply it thick if needed to allow leveling of the transducer. Make sure there are no air bubbles trapped (you can test the transducer before the urethane sets). I think the PVC pipe idea works well but isn't really that advantageous.

This method probably does decrease the power of the transducer through the water, but for the reasonably shallow depths that most are concerned with it makes no difference.

[rwidman]

Originally Posted by Cuttyhunk

Do you use it for fishing? I just bought this transducer thinking it was a through-hull. I am fine with not drilling a hole as long as we will see fish!

I don't use it for fishing but if I switch my plotter to the "sonar" mode, I see fish symbols at times.

The process is the same, sound waves bouncing off the bottom or in this case, fish. What it won't tell you is the water temperature.

[belizesailor]

Originally Posted by rwidman

...

The process is the same, sound waves bouncing off the bottom or in this case, fish. What it won't tell you is the water temperature.

Good point, for those with a temp probe it wont be accurate with any kind of bonding, but I expect a fluid filled mount would be close.

[CarinaPDX]

If buying new transducers simply buy the depth sounder (only) puck and get the combined knotmeter/temp which has to go through the hull.

[Peters Wet]

Well i just sent away for the p79 unit that fits my chartplotter application, Ill let yall know how it works out . Thanks for all the advice

[Ziggy]

Originally Posted by Peters Wet

Well i just sent away for the p79 unit that fits my chartplotter application, Ill let yall know how it works out . Thanks for all the advice

Good choice. I think you'll be happy with it.