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Your transducer is most definitely located over a water ballast area without a doubt, not sure why you think its not, just take a peek inside your drain gate valve, it should be pretty clear as to whats ballast and what isn't.

raycarlson wrote:Your transducer is most definitely located over a water ballast area without a doubt, not sure why you think its not, just take a peek inside your drain gate valve, it should be pretty clear as to whats ballast and what isn't.

I don't understand why his depth sounder would have worked when the tank was empty.

I'm not clear what this photo is showing.
What is the orange colored stuff that looks like it's squished between two layers of something.


I believe others have mounted the transducer under the steps next to the batteries or under one of the side lockers. The locations I've seen would still place it in the dark area of this photo.

I've never fully understood where the ballast is. There seems to be some disagreement as to where it is.

In my mind, the red areas are where the channels are raised above the hull. This is where I believe ballast to be. Some have mounted transducers in the battery compartment which would be the dark gray area in the center. This seems solid to the hull in my boat. Others claim the gray area is ballast which doesn't make sense to me. The ballast is best on the sides. However there seems to be a LOT of ballast in the bow. *shrug* I don't get it.


I will have to shine a light and camera into the gate valve to see for myself what's in there.

--Russ

Yeah well that's how I thought it was too Russ, but okay, will have a look at the gate valve when I get the boat out of the water in a few weeks, but still, I don't see why it worked perfectly fine for approximately three years, and most of the time, we run with no ballast in

My bet is that while you think you were running with no ballast in, there was actually some water in there and if you were stern heavy, that is where it would collect. Have you changed the loading of the boat recently adding more weight to the bow? Even a passenger or two riding below or forward instead of in the cockpit could change the attitude of the boat.

RobertB wrote:My bet is that while you think you were running with no ballast in, there was actually some water in there and if you were stern heavy, that is where it would collect. Have you changed the loading of the boat recently adding more weight to the bow? Even a passenger or two riding below or forward instead of in the cockpit could change the attitude of the boat.

Interesting theory.

Paul, you could settle the question once and for all by drilling a small hole where the transducer is. If it comes out the bottom, we know there is no ballast. If it goes into a void, ballast it is.





I'm kidding of course. Don't do that.

--Russ

As you can see in these snips, there is definitely water between the tubes. The first one is of the transom area. (note the engine cutout) and the second is the area with the galley in the forward position.





As was suggested, perhaps the ballast was not quite empty and in the bow high position, what water that remained went to the stern area.

~Rich

If there is a small amount of ballast in there, it could possibly work as Robert described.

So, would it be safe to place the transducer outside of the ribs in the hull? Angle it so it's perpendicular.
Where do folks mount their internal transducers?


--Russ

Going back, I found this post

"I have a thru hull transducer mounted just in front of the batteries at the base of the stairs. It works very well although you have to have the ballast full of water. "

Which would support the ballast chamber is as Robert describes.

Eh, since he's pulling it off anyway, I would simply mount it here.


--Russ

Mounting outboard of the ballast tank is proper - but the mount needs to accommodate the angle of the hull. I seem to remember instructions, possibly included with my transducer, that details how to mount the transducer horizontally to an inclined hull. I believe it relies on a bunch of RTV. Check with the transducer manufacturer. For this reason, I chose a mounting on the outside of the hull.

RobertB wrote:Mounting outboard of the ballast tank is proper - but the mount needs to accommodate the angle of the hull. I seem to remember instructions, possibly included with my transducer, that details how to mount the transducer horizontally to an inclined hull. I believe it relies on a bunch of RTV. Check with the transducer manufacturer. For this reason, I chose a mounting on the outside of the hull.

There are lots of expensive and complicated devices


I'm cheap and not that fancy.

Here's how I've done it in the past. Glob LOTS of silicone into the bottom and eyeball it so it looks level. Tape it in place until the caulk sets up. The plastic bowl it to keep any caulk from running out, although it never has.


My transducer is on the transom and pivots to adjust the the angle of the transom. Many times this has gotten bumped and it was aiming towards the back of the boat. I don't think it's that critical (heeling etc.) to be perfect unless you are in deep (200' +) water in which case I'm not worried about depth.

--Russ

Well my wife will have fun with this since she originally pointed out that the transducer must be mounted over ballast and I told her she's silly, as it had worked fine for years


Only change in loading is that recently we turned the rear compartment into a storage area and started using the table as the other bed. However that was well after the problem started.

So that's it then... The theory that there has been some ballast in there sounds reasonable, but the problem with that is that I usually let the ballast drain out completely on the ramp, and in the past, the depth reading always just worked when I put the boat in the water after that. Also I have checked it from empty ballast ,, to open gate and wait -- and my guesstimate is that it starts working once about half full. I'm pretty confident I haven't had the ballast half full all the time, but yeah,,, what else could it be I guess....

Anyway, might silicon an angled wooden shim on the area outside the ballast tube, and silicon the transducer onto that - that should solve it I guess/hope ??

Mac26Mpaul wrote:Anyway, might silicon an angled wooden shim on the area outside the ballast tube, and silicon the transducer onto that - that should solve it I guess/hope ??

NOOOO! Don't use a wooden shim. That will act like an air void.

I would glob tons of caulk and then plant it in the glob and tilt it to be roughly perpendicular.

--Russ

mmm alrighty then, when I get around to it (at least a few weeks), I will report back with the outcome,

Thanks as always for the collective knowledge and ideas

RussMT wrote:I've never fully understood where the ballast is. There seems to be some disagreement as to where it is.

In my mind, the red areas are where the channels are raised above the hull. This is where I believe ballast to be.



--Russ

No no no! This is wrong! The ENTIRE AREA between the channels is flooded! There is water in between too - that is a double hull there in the area between the channels and it definitely floods when full so a sounder will not work there unless the ballast is totally full and even then it will be problematic.

This the the unit I use and it's seems to be the only inside hull one I have had work well every time :



It's is needed because you need somthing that can take the angles you will encounter when you are not over the ballast tank. I have this under the dinette seat.