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I would like to add a depth sounder to my boat (26s). I would be most interested in sounders with "shoot though" type transducers. Like the Norcross Hawkeye. There is a place in the lazarette where I could mount the transducer but would have to glass in a small flat place to mount the transducer to shoot straight down. The most logical place to mount the transducer would be just inside the v-berth where there is a large flat area. But...there it would have to shoot through the ballast tank i.e. through 2 layers of fiberglass separated by about a foot of water. Anyone have experience with this? Mike

If you do a search you will probably find lots on this.

Mine is mounted on the transom and also measures water temp.
However, on my last boat what I did was cut the bottom out of a butter container. I then placed the container where I wanted to mount the transducer inside the hull, then squished out a ton of GE clear silicone caulking into the bottomless container. I then pressed the transducer into the caulk and aimed it flat. The container keeps the caulk from oozing everywhere.
It worked like a charm and if it didn't, I could easily cut the caulking away and try something else.

Yes, you will want to mount it where it doesn't have to shoot through the ballast tank.


--Russ

Non through hull sounder manuals will suggest the same thing for off level bottoms (the silicone trick) same effect as building up a flat surface with glass, only easier.

MD Dunaway wrote:I would like to add a depth sounder to my boat (26s). I would be most interested in sounders with "shoot though" type transducers. Like the Norcross Hawkeye. There is a place in the lazarette where I could mount the transducer but would have to glass in a small flat place to mount the transducer to shoot straight down. The most logical place to mount the transducer would be just inside the v-berth where there is a large flat area. But...there it would have to shoot through the ballast tank i.e. through 2 layers of fiberglass separated by about a foot of water. Anyone have experience with this? Mike

I put my transducer into an "obvious perfect" place on my 26X, but had the ballast tank full when I chose the spot ... later I discovered my mistake, by losing my depth readout when I was running fast on plane with the ballast tank empty. (Oops! Need a "blush" icon for forum posts; how about it, Heath?) I haven't moved it because it's still "obviously perfect," as long as I'm sailing - I don't run "ballast empty" in the shallows.

I put a Hawkeye on my with the transducer inside the hull, and I was quite satisfied with it. I did that one with the ballast tank empty in the first place, though.

The Hawkeye is a good little depth-sounder and it takes a bare trickle of current. I was quite pleased with it, and I believe you'll find it good too. I might add one to Bossa Nova if I ever get that nervous about my combined GPS/fishfinder conking out on me....

(BTW, have you seen the "wet box" method of mounting a transducer? If you're going to the trouble of glassing in a flat pad, this might be better. Glass in a short, large-diameter piece of PVC pipe, as a cylinder sticking up from the hull. Mount your transducer inside that so it's plumb, with a waterproof gland in the side of the cylinder for the transucer's wiring. Fill the cylinder with mineral oil and cap it ... then, if something goes wrong and you have to replace the sounder, it's easy to un-cap the cylinder and swap out the transponder.)

Good luck - Rick

Hey! Rick...stealing my thunder,,,I don't mind...
But use cheap vegetable oil from the supermarket...$1.50 a litre...
engine oil costs a lot more and it might have additives that could attack the fibreglass...
the drawback with this is that you lose the readout from any speed wheel or temperature sensor...even though the water temp. can draw down the oil temp to fairly close...even through the hull...cheers...puggsy

Rick

Just to be clear are you saying that it WILL shoot through the ballast tank? I know that will produce a false reading (because the measurement is to the transducer and not the bottom of the boat), but that's OK. Will it shoot through the ballast tank? If not I'll go with the silicone method in the lazarette. Maybe a little more elaborate version like taking a large PVC pipe and shaping it to the bottom of the boat and glassing it in. Then filling it with silicone. This will allow me to also remount my bilge pump just aft of it. With the 26s I don't have to worry about going on plane.

Thanks for all the helpful information!!

Mike

Yes, it DOES shoot through the full ballast tank. Mine has since last April, when I tested my "not-quite-right" position for the sounder. But if you have a position that suits you - that won't be above the waterline on either tack - that would be better. (I wish they hadn't left that little gap between the hull and the ballast-tank molding, on my 26X. The corresponding area on my 19 was epoxied together and solid. I might consider a bit of drilling and filling with epoxy this winter, while the boat is high and dry.)

The "false reading" isn't a problem on our boats; it amounts to a few inches at most. I would regard it as a "safety margin," because the sounder is telling how much water is under your boat - which is less than the water depth from the surface. A salutary warning, right?

(Apologies for stealing your thunder, Puggsy. "You're da' man" when it comes to this mod.)

MD Dunaway wrote:Rick

Just to be clear are you saying that it WILL shoot through the ballast tank? I know that will produce a false reading (because the measurement is to the transducer and not the bottom of the boat), but that's OK. Will it shoot through the ballast tank? If not I'll go with the silicone method in the lazarette. Maybe a little more elaborate version like taking a large PVC pipe and shaping it to the bottom of the boat and glassing it in. Then filling it with silicone. This will allow me to also remount my bilge pump just aft of it. With the 26s I don't have to worry about going on plane.

Thanks for all the helpful information!!

Mike

Thanks!

I have my depth sounder on the transom, but would really like to have it as far forward as possible. I can't really tell how far forward the ballast tank goes. We sometimes go without ballast so don't want to put it over the ballast tank. Does anyone have a drawing of the showing the most forward point of the water ballast? Is there any reason not to place it far forward? I'd like to see out as far forward as possible!

Thanks.

1997 SILK

Yea! Going in close to shore to offload or tie up for the night. even with a 26ft boat I'd like to know how deep the water is up there (as close to the bow as possible).

Farther forward on an X, or M might be nice when sailing, but when powering, the bow comes up and you might not keep water under the transducer.

~Rich

MD Dunaway wrote:I would like to add a depth sounder to my boat (26s). I would be most interested in sounders with "shoot though" type transducers. There is a place in the lazarette where I could mount the transducer but would have to glass in a small flat place to mount the transducer to shoot straight down. Anyone have experience with this? Mike

Mike
I had great results with the transducer in the lazarette of my prev boat, 92 Mac 26-C. The dealer put the unit in the laz. for the prev. owner, and I upgraded to a better unit, fish finder/depth finder combo. I installed the new transducer the same way.
The installation was done with silicone, with the transducer flat on the Laz. floor, and a large amount of silicone surrounding it (with no bubbles). Its a very easy installation. Works great too.

Ive done the same installation (with silicone) on my 26-X, with the transducer flat on the floor under the galley.

One other alternative;

If your transducer came packaged with the 'optional mount' bracket for trolling motors, you may find the bracket will fit the gate valve outlet on the stern.

Me, being one who hates to drill holes in boats found this to be an excellent choice. I ran the cable through the pre-existing motor cable/wire harnes that passes through the transom bulkhead and up through the console. A breeze to run and took only an hour at the most.

Works really well and also alows the temp sensor feature to operate as opposed to being inside the hull.

Here's a pacture of it;



... and a pacture of where the wirse run;



Big T

Hamin' X wrote:Farther forward on an X, or M might be nice when sailing, but when powering, the bow comes up and you might not keep water under the transducer.

~Rich

Good point.

Also, a transducer 15' more forward in practice doesn't give you much warning. We would all love a forward looking sounder.


--Russ

Yes of course. At 6 miles per hour putting the transducer forward 15' gives an "advance warning" of 1.7 seconds and at 15 miles per hour .68 seconds. Still if I'm not sure of the depth I would want to go in (slowly) with the bow and not with the stern. At cruising speeds it probably doesn't make much difference. Still, if the transducer worked equally well in either location I would rather know the depth of water under the bow.