Transducer placement on a 18.5 Hunter

[Revv up]

Got a Garmin Striker plus 4 to act as a depth finder, the plan is to mount the transducer in a sealed container (full of liquid) at the back of the hull. I’m wondering if I really need to cut the bottom of container out as if it’s going to read through the fibreglass will another couple thou of plastic matter?

Also the location is probably about 5 ^ off level... being that the boat is going to be heeled over most of the time anyway.... do I really need to bother getting it level?

Lastly should the transducer be suspended in the liquid or can it just rest on the bottom of the container. I haven’t found a good instruction video that addresses these questions.

 

[Ralph Johnstone]

Where this "place in a liquid" crap comes from is anyone's guess.

Check the archives on this site to see how in-hull transducers are mounted in such things as toilet bowl wax, silicone sealant and other such air free materials. Also do a search to find out if your chosen location will be suitable as far as hull transmission goes.

 

[Johnb]

And if at all feasible forward of the keel. Aids ooching up to ramps or banks

In any event aye to avoiding a hole in the hull.

 

[Revv up]

Where this "place in a liquid" crap comes from is anyone's guess.

From the GPS store, I would have thought they were a reliable source, who knew

 

[rgranger]

Where this "place in a liquid" crap comes from is anyone's guess.

Check the archives on this site to see how in-hull transducers are mounted in such things as toilet bowl wax, silicone sealant and other such air free materials. Also do a search to find out if your chosen location will be suitable as far as hull transmission goes.

I've mashed one into a wad of plumbers putty once. It worked great for two years before I sold the boat.

 

[dlochner]

Depth transducers work by sending out high frequency sound waves. When mounted in a hull, they must be mounted in such a manner to allow the sound waves to travel from the transducer through the fiberglass down to the bottom and back up. There are many ways of mounting that can accomplish this, a thin layer of silicon caulk with out any air bubbles, epoxy without any air bubbles, or in a liquid bath, oil, antifreeze, or water. The key is to allow the sound waves to transmit freely with the least interference. A liquid bath is the most effective and efficient.

In the worst case scenario, poor transmission will significantly reduce the effective range and accuracy of the transducer. Substances like wax, balsa core, thick layers of silicone or other caulk will slow the transmission of the sound waves and give inaccurate readings.

 

[Revv up]

I've mashed one into a wad of plumbers putty once. It worked great for two years before I sold the boat.

And I just happen to have a small tub of plumbers putty left over from a small plumbing job. That will also give me the freedom to move it easily for I need to..... and getting air bubbles out of it should be a snap. Great, this makes what could have been a miserable experience in a cramped space a very quick job.

 

[Ken Cross]

I mounted ours in wax (from a new $0.99 toilet ring) until I was sure where I would place it. Once I was sure, I cleaned the transducer and hull with solvent on a rag. Then I glued it in place with 3M 4200. It works great and stays in place.

Ken

 

[Benny17441]

You can put it in a plastic bag filled with liquid and test the location where you want to set it. The requirement is that there be no air bubbles between the plastic and the hull and that you have an uninterrupted shot to the bottom of the water. The location should be as level as possible to get an accurate reading; a few degrees will not make much difference to a depth of 10' but at deeper depths the discrepancy will grow. For a sailboat it does not matter where the transducer is located whether next to the bow or the stern as long as you have a clear shot to the bottom. whether immersed or suspended it does not matter, the only thing is that the transducer cannot shoot through air. I once set the bottom of a transducer in a thin pool of epoxy and it worked and remained affixed to the hull until I took it off a couple of years latter. Others use the wax seal for a home toilet installation. Water or oil can be used as the liquid. my problem with rigid containers is that it may not fit flush with the hull and allow air to get in between. Like I said my preference would be either epoxy or wax. Just test the location before affixing. I don't know if you are familiar with the uses for a depth sounder in a boat but I'm going to mention the most important, 1) To slowly approach a shallow area 2) to determine anchoring depth and calculate the required rode scope 3) to double check your position in a marine chart by matching the depth indicated to the actual reading 4) IF you rely on tides to be able to exit and enter into port a depth meter can help you estimate the wait for the water to reach a certain depth. It is an instrument that you must glance at periodically to confirm your believed course and position. If you are going out of an inlet and the depth should be 10' and all of a sudden you see 5' in the depth meter you know you are likely off course. Many a times have had to make a 180 to backtrack on the original course.

 

[dlochner]

For a sailboat it does not matter where the transducer is located whether next to the bow or the stern as long as you have a clear shot to the bottom.

The transducer should be placed where it will see clear water not turbulent water. The clearest water will be forward ahead of the keel or centerboard. The most turbulent water will be just aft of the keel or centerboard.