Thru-hull transducer help. Depth + temperature (no speed)?

[mvweebles]

I have an air mattress p79 basic 200hz depth sounder transducer. What I'm missing from any of my devices is water temp. Hoping there's a depth/temp transducer out there but they all seem to be tri-data with paddlewheel STW capabilities. Hoping to avoid the paddlewheel since the foul so easily and I just hate something installed that isn't working properly.

Thoughts? Hoping to avoid installing a second through hull and running a second N2K cable.

Thanks in advance.

Peter

 

[psneeld]

If all you need is water temp, a lot of people just use a simple sensor in the engine intake/seacock....that is if you don't care about speed through the water (after sailing felt that was a pretty useless piece of equipment).

You can use a homegrown setup or a bastardized commercial one.

 

[rslifkin]

My basic depth transducer is an Airmar P319 50/200 unit. It's directly connected to a Lowrance plotter/sounder, but gives both depth and water temp. I do think the water temp gets skewed slightly high (a couple degrees) from engine room heat hitting the top of the transducer once the boat has been running for a while, at least when it's not moving through the water.

 

[twistedtree]

What is the transducer connected to? You Simrad MFD? Assuming so, I'd start there. In the menus for the sounder, there is likely a drop down that lists supported sounders. If not there, you can probably find it in the manuals. Also, a call the Gemeco (the distribution and support arm of Airmar) with your current exact model transducer and model MFD and they can probably tell you what is the easiest replacement with temp.

 

[O C Diver]

Many / most MFDs that use the Airmar transducers through the NEMA 2000 network have the ability in the configuration menu to calibrate the temperature (measure water temp and adjust display) just as you can adjust water depth for either surface or keel depth. The adjustment is in the transducer chip, so it reads the same on all displays.

Ted

 

[Insequent]

I gave up on tranducers giving temp. Sure they work for a time, but then the sensor fails and either does not provide a reading or gives a reading that is 250% of the actual water temp. If I really want to know water temp I dangle a fridge thermometer sensor cable into the water at anchor.

I had not thought of the engine water intake. Is it a thermocouple on the metal fittings, or do you drill a hole and screw in a probe in a similar manner to EGT sensors. Anyone have any brands/models of sensors?

 

[psneeld]

I gave up on tranducers giving temp. Sure they work for a time, but then the sensor fails and either does not provide a reading or gives a reading that is 250% of the actual water temp. If I really want to know water temp I dangle a fridge thermometer sensor cable into the water at anchor.

I had not thought of the engine water intake. Is it a thermocouple on the metal fittings, or do you drill a hole and screw in a probe in a similar manner to EGT sensors. Anyone have any brands/models of sensors?

A thousand possible ways/pieces of equipment.

A serious sportsfisherman may want a definite 1/2 degree temp break.... some cruiser is happy with a couple degree accuracy to wear a lightweight wet suit or not.

My input is from 20 years ago, there must be some great solutions now....especially with all the bluetooth/wifi equipment.

 

[Insequent]

Scott you are right, lots of options. I have a surface mount Victron battery temp with bluetooth. So first up I'll try sticking it on the engine cooling water plumbing although it might not work all that well on a curved surface.

 

[twistedtree]

I gave up on tranducers giving temp. Sure they work for a time, but then the sensor fails and either does not provide a reading or gives a reading that is 250% of the actual water temp. If I really want to know water temp I dangle a fridge thermometer sensor cable into the water at anchor.

I had not thought of the engine water intake. Is it a thermocouple on the metal fittings, or do you drill a hole and screw in a probe in a similar manner to EGT sensors. Anyone have any brands/models of sensors?

Just curious, have you lost temp on a transducer that is connected to an MFD or fish finder, or only one a so-called Smart Transducer that is directly connected to N2K? I ask because the N2K Smart Transducer have had years of poor quality and failures. I went through three on my last boat in as many years. But I have never had any issues with transducers that connect to a fish finder or MFD.

 

[Insequent]

Three failures, none on N2K Two connected to a Furuno FCV sounder. The other was connected to a Simrad MFD. All were a few years ago now.

 

[Hippocampus]

Find an accurate on going water temp is helpful if near shore or offshore. Helps you know where currents are. Commonly used when crossing or utilizing or avoiding the Gulf Stream as an example. But for our current coastal travels just dropping a thermometer over the side has been sufficient. Could see an ongoing temp reading as being helpful if you fish a lot. Particularly for pelagic fish. Otherwise have taken to KISS.

 

[mvweebles]

My mission-critical reason for wanting water temp is because Cheryll, my wife, won't go in the water unless it's close to 85F. And I thought it would be easy so just plain ole curiosity. Noting magnificent or seamanlike (except for maybe mermaid fascination).

Peter

 

[psneeld]

My mission-critical reason for wanting water temp is because Cheryll, my wife, won't go in the water unless it's close to 85F. And I thought it would be easy so just plain ole curiosity. Noting magnificent or seamanlike (except for maybe mermaid fascination).

Peter

For that, get a pool thermometer and toss it over the side...no simpler than that.

 

[rslifkin]

My mission-critical reason for wanting water temp is because Cheryll, my wife, won't go in the water unless it's close to 85F. And I thought it would be easy so just plain ole curiosity. Noting magnificent or seamanlike (except for maybe mermaid fascination).

Peter

That's our primary use for it too. Knowing water temp for swimming is a nice convenience.

 

[twistedtree]

Three failures, none on N2K Two connected to a Furuno FCV sounder. The other was connected to a Simrad MFD. All were a few years ago now.

Thanks, that's very interesting. My most recent "smart" transducer (DT800) has been working well for 3 years now, so maybe they fixed whatever the problem was.

Gotta love those FCV sounders

 

[Insequent]

For that, get a pool thermometer and toss it over the side...no simpler than that.

The problem with those is that they read temps close to the surface. There is usually a much warmer surface layer that you will go below when jumping in for a swim...

 

[Hippocampus]

Insequent has it right. How deep is the thermocline varies greatly. Tends to be less of a thermocline in shallow waters where surf causes mixing but quite defined in deep ocean waters. If you’re fishing, snorkeling or diving knowing how deep the thermocline is can be a very valuable piece of information. You may need a wet or even dry suit if wreck diving even though you’re in the tropics when you expect to be below it.
Fishing there’s the same issue. Cold water tends to hold more oxygen but warm water more plankton and the fish predators target. Fish will tend to cluster right at the thermocline. Darting up to feed and down to rest. You generally want the predators that are teleosts ( bony not sharks). So you generally want to identify where the bait fish are (and birds) but troll just above the thermocline. Especially if you are targeting fish like stripers(rock fish) or mahi mahi.
However a simple thermometer you can drop over the side on a long string is more than adequate. In actual usage a transponder gives you less useful information as you only read surface temperature. I use a very thin piece of dyneema on a Cuban yo yo and a couple of sinkers so it sinks fast and doesn’t trail much behind the boat. I’d like to find a thermometer with a wire spool that would allow me a reading without having to take the thermometer out of the water to read it. Can’t find anything at a reasonable cost.My main use is fishing now. For swimming or diving would think that complexity is unnecessary.

Does anybody know of a water thermometer you can read without taking it out of water?

 

[rslifkin]

Transducer temp has always been good enough for swimming for us. Transducer is about 20" below the surface. And if I switch to sonar view the thermocline is often visible. Around here it's usually 4 - 5 feet down anywhere we'd swim. So you're warm unless you get vertical in the water, then you get cold feet.

 

[psneeld]

You can rig to be a cruiser, or an oceanographer. You eqipment and budget determine as well as patience.

Give me an issue and I can recommend a solution, keep moving the goalpost and This is where threads go.

 

[Newtrawlerowner]

I have an air mattress p79 basic 200hz depth sounder transducer. What I'm missing from any of my devices is water temp. Hoping there's a depth/temp transducer out there but they all seem to be tri-data with paddlewheel STW capabilities. Hoping to avoid the paddlewheel since the foul so easily and I just hate something installed that isn't working properly.

Thoughts? Hoping to avoid installing a second through hull and running a second N2K cable.

Thanks in advance.

Peter

Peter,
I had a similar issue. My tri-ducer was made by Airmar. My issue was both temp and speed. They made a speed/temp retrofit kit that lets you remove the paddle wheel and install an insert. As long as the depth works, this kit gets you the STW and water temp. signals. The kit I bought was part# B744V-INS-JB.. I purchased it from iMarine.com.
You might want to contact Airmar US office, Gemeco Help Desk, 1141 S. Ron McNair Boulevard, Lake City, SC 29560, Phone: 803-693-0777 or email them at gemecoinfo@airmar.com. They make 2 different kits depending on the length of your paddle wheel insert.