Transducers for depth
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No, they are limited by hull composition.
See reply #7 for testing a hull.
https://forums.sailboatowners.com/index.php?threads/depth-transducer.140078/&highlight=depth
Hey @Ralph Johnstone , who can we talk into pulling the existing one out of the hull to test that theory with?
Depends on how soon you can get your boat out here to the coast
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So, I guess we are both correct. My question should have been: What is the hull made from, multi-layer composite, or solid fiberglass. Also if it is fiberglass, how thick is it"
From the Garmin website:
An enclosure filled with propylene glycol is the best mounting option for many boats. It works well on single skin G.R.P. (completely fiberglass) hulls, but is not suitable for sandwich construction, steel, aluminum, Ferro Cement, or wooden hulls. The ultrasonic signal produced by the transducer passes easily through liquids and solids but is greatly attenuated in air. Therefore, it follows that air inclusions in the fiberglass or a stream of air bubbles on the outside of the hull will both affect performance. The signal will pass through up to 0.75" thickness so avoid sitting the transducer over spray rails or reinforcements.
From the Garmin website:
An enclosure filled with propylene glycol is the best mounting option for many boats. It works well on single skin G.R.P. (completely fiberglass) hulls, but is not suitable for sandwich construction, steel, aluminum, Ferro Cement, or wooden hulls. The ultrasonic signal produced by the transducer passes easily through liquids and solids but is greatly attenuated in air. Therefore, it follows that air inclusions in the fiberglass or a stream of air bubbles on the outside of the hull will both affect performance. The signal will pass through up to 0.75" thickness so avoid sitting the transducer over spray rails or reinforcements.
1. If you take out the old transducer and the sealant/adhesive damages the hole on the way out, you'll definitely be sorry rather than safe.
2. The boat we installed the non-thru hull on was a 41' Catalina. Hull thickness ? Probably greater than yours.
3. Test the non-thru hull first and if it doesn't work ..................... return it to Waste Marine (carefully repackaged) and say you bought the wrong one.
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Yes, I can see your quandry but no, unfortunately I can't see an easy way to test the non thru-hull out of water.
Hull thickness has nothing to do but if the hull is porous it will not work as these transducers cannot shoot through air. Sorry a permanent non-thru hull installation of a transducer requires that the desired location be verified as non porous. Once the boat is in the water stick the transducer in a plastic bag and fill it with water to completely submerge it. Lay the bag flat against the hull (no air) and test different locations before a final semi-permanent location is chosen.
BUUUUUUUUT .......................... if he can't find a suitable place to mount the non thru-hull once he's back in the water, he's stuck without a depth sounder until the next time he hauls out and replaces his thru-hull depth sounder.
Installed one on our boat several years ago and it works great. Ours is mounted next to the shaft strut. Most all Hunters were built with solid FRP below the waterline; yours should be also. I tested my location by placing the transducer in a small dam of water using masking tape.
My 1984 25.5 hunter hull thickness was 1/4 inch. I removed the depth sounder to replace it since it's retaining ring was broken and water was leaking in. No damage to the hull. Since your boat is already out of the water I would recommend replacing it.
To test it I placed it on the surface of a swimming pool water with know depth.
To test it I placed it on the surface of a swimming pool water with know depth.
I stuck mine down https://www.nasamarine.com/product/depth-transducer-with-7-metre-cable/ with this or similar http://www.marineadhesive.nl/products/msr-ca-construction-adhesive
I stuck just the flat end of the transducer to the inside of the hull. As mentioned though any air bubbles either in the GRP or adhesive will effect the performance.
I did it also with a fishfinder transducer and it worked spot on.
I stuck just the flat end of the transducer to the inside of the hull. As mentioned though any air bubbles either in the GRP or adhesive will effect the performance.
I did it also with a fishfinder transducer and it worked spot on.
This does not help with your question on thickness of the hull, this might help with placement. If you go to the top of forum, click on boat information, Hunter, 25.5, scroll down the sample photos and there is one showing the location where someone had glued in their transducer. This is where I placed my transducer in silicone on my 84 25.5 and it worked very well.