I have Mac 26 M, and want to install a "shoot thru" transducer for a depth sounder. I do not want to cut a hole in the bottom for a "through hull" transducer. I like the idea of the transducer being inside the hull, not attached to the transom, which I guess is my only other option. A "shoot thru" is glued to the inside of the hull bottom, and will work when the hull is solid fiberglass, which does not impede the sonar pulse as it passes into the water. On the Mac 26 M, however, it looks like the transducer would have to shoot through the top layer of the water ballast structure, then through ballast water and then through the hull. Will this work? Any other options?
installing a depth sounder transducer
- Thread starter Dayski
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Nope
You need to locate a spot on the hull bottom that is not over the tank or permanent ballast. Or you could transom mount one. I'm sure there are some M owners here that can tell you a spot that works.
You need to locate a spot on the hull bottom that is not over the tank or permanent ballast. Or you could transom mount one. I'm sure there are some M owners here that can tell you a spot that works.
Shoot thru balast tank
It will shoot thru the balast tank if it is full. Use a glob of silly putty to test the best spot first. I had mine near the bow for less turbulance. Pls remember the tank must be full. If you're on plane, it will not work.
It will shoot thru the balast tank if it is full. Use a glob of silly putty to test the best spot first. I had mine near the bow for less turbulance. Pls remember the tank must be full. If you're on plane, it will not work.
Window putty
I used some window putty from home depot to stick it to the hull. Took it off 3 yrs later. That stuff was still sticky like day 1. Worked fine.
I used some window putty from home depot to stick it to the hull. Took it off 3 yrs later. That stuff was still sticky like day 1. Worked fine.
TRANSDUCER MOUNTING
Here is how I fitted mine. Take a short length of 6-9 inch diameter PVC water pipe and cut one end of it on an angle of about 15 degrees. Pick a spot on the inside of the "M" hull away from the ballest section. I chose under the galley in its forward position.Rotate the angle cut on the sloping inside hull so that the top of the pipe is level. Using a quality rubber silicone, stick the angled end straight to the hull so that the top/other end is level/parallel to the water..or your back deck...mount the transducer to the wall of the pipe in the same way you would mount it on the bottom edge of your transom.It needs to be just a couple of inches above the hull. but not touching the hull. Lead the cable out through a small notch cut or filed in the top edge of the pipe. From the hardware shop buy a stick on or screw on cap that fits the pipe. into it drill about a 3/4 inch hole [ about in the centre] that can later be plugged with a tapered rubber plug or cork. with the TRANSDUCER mounted inside the pipe,and sitting level, silicone the cap/lid on and let it set.including around the exiting cable...so that the whole unit is leakproof. Then fill to the top with cheap vegetable oil trying to leave no air in the whole unit. plug it off and seal around the plug. The reason for using silcone instead of hard setting glue is that if the transducer ever fails,and you have to replace it, you can unseal the silicone, which you cannot do with glue or epoxy. The signal beam will go through the oil, then the glass hull, then water, and only come back as a signal when it passes through a fishes air sac or bounces off the bottom...The transducer is fully protected and you can store stuff around it...which you cannot do with just a wax or compound seal. also the oil guarantees no air between the transducer and the 'target'...It works fine for me...My previous boat, plywood hull, had two sounders both with "wet boxes" which the above is...Regards...pugs.
Here is how I fitted mine. Take a short length of 6-9 inch diameter PVC water pipe and cut one end of it on an angle of about 15 degrees. Pick a spot on the inside of the "M" hull away from the ballest section. I chose under the galley in its forward position.Rotate the angle cut on the sloping inside hull so that the top of the pipe is level. Using a quality rubber silicone, stick the angled end straight to the hull so that the top/other end is level/parallel to the water..or your back deck...mount the transducer to the wall of the pipe in the same way you would mount it on the bottom edge of your transom.It needs to be just a couple of inches above the hull. but not touching the hull. Lead the cable out through a small notch cut or filed in the top edge of the pipe. From the hardware shop buy a stick on or screw on cap that fits the pipe. into it drill about a 3/4 inch hole [ about in the centre] that can later be plugged with a tapered rubber plug or cork. with the TRANSDUCER mounted inside the pipe,and sitting level, silicone the cap/lid on and let it set.including around the exiting cable...so that the whole unit is leakproof. Then fill to the top with cheap vegetable oil trying to leave no air in the whole unit. plug it off and seal around the plug. The reason for using silcone instead of hard setting glue is that if the transducer ever fails,and you have to replace it, you can unseal the silicone, which you cannot do with glue or epoxy. The signal beam will go through the oil, then the glass hull, then water, and only come back as a signal when it passes through a fishes air sac or bounces off the bottom...The transducer is fully protected and you can store stuff around it...which you cannot do with just a wax or compound seal. also the oil guarantees no air between the transducer and the 'target'...It works fine for me...My previous boat, plywood hull, had two sounders both with "wet boxes" which the above is...Regards...pugs.
Test in water bag - then epoxy in place
The manufacturer of my depth-finder says it's best to mount an in-hull transducer forward of the daggerboard/centerboard, as near the keel as possible - and don't worry if it isn't perfectly plumb; the sonar beam spreads enough to work at a reasonable hull angle. You can test a spot for installation by putting the transducer in a plastic bag, full of water and twist-tied shut, and placing it on the patch of hull where you'd like to install the transducer. If it's on your hull, or on the full ballast tank (no air gaps), you should get a good reading. I'd be skeptical of any kind of putty, especially if the sounder doesn't seem to be working in "that spot where it should". I tried sticky wax, from a recommendation on another Mac board, but the signal didn't shoot through the wax! Tried several sites with no results, then dipped the transducer in the water beside the boat and got "---" on the display. Wiped off the wax, tried it in a "wet bag", and the transducer worked just fine inside my hull. Cap'n Pug's "wet-box" is the solid-gold way to install a transducer, and you can make it perfectly level in the box, but I just glued mine in place with slow-cure epoxy (as per the manufacturer's instructions). If I ever have to replace it, I'll trim its cable close and glue the next one beside it. Hope this helps!
The manufacturer of my depth-finder says it's best to mount an in-hull transducer forward of the daggerboard/centerboard, as near the keel as possible - and don't worry if it isn't perfectly plumb; the sonar beam spreads enough to work at a reasonable hull angle. You can test a spot for installation by putting the transducer in a plastic bag, full of water and twist-tied shut, and placing it on the patch of hull where you'd like to install the transducer. If it's on your hull, or on the full ballast tank (no air gaps), you should get a good reading. I'd be skeptical of any kind of putty, especially if the sounder doesn't seem to be working in "that spot where it should". I tried sticky wax, from a recommendation on another Mac board, but the signal didn't shoot through the wax! Tried several sites with no results, then dipped the transducer in the water beside the boat and got "---" on the display. Wiped off the wax, tried it in a "wet bag", and the transducer worked just fine inside my hull. Cap'n Pug's "wet-box" is the solid-gold way to install a transducer, and you can make it perfectly level in the box, but I just glued mine in place with slow-cure epoxy (as per the manufacturer's instructions). If I ever have to replace it, I'll trim its cable close and glue the next one beside it. Hope this helps!
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