Ideas on getting lake water temp sensor w/o drilling into hull?

[hostage]

I have concluded that searching for anything related to water temp sensors tends to brings back search results for telling you the coolant temp of your engine. I know some speed sensors and transducers have an included water temp sensor, though I don't have one and don't want to drill a hole in my boat. My 2011 Regal 2300 has a VolvoPenta 5.7Gi w/ Duo Prop. Has anyone tried doing one of the followings:
1) Putting an inline temp sensor in the raw water pickup hose?
2) Modfying a brass plug to take some type of temp sensor. Would need to think more about the engineering on this one.

 

[flashback]

I like your idea but... always a but.. water passing through the out drive will be a bit warmer than the water in the pond...if accuracy is not needed it seems a great idea...

 

[alldodge]

I had a deck drain that came out under the swim deck and ran the cable from the Dept/Temp sensor thru the drain. Tie-wrapped the sensor to the trim tab.

 

[roscoe]

Any $99 fish finder will have a temp sensor.

What is so important about this if you are not fishing?

 

[alldodge]

What is so important about this if you are not fishing?

For me was to find out if it's warm enough to jump in

 

[Scott Danforth]

My Garmin tells me the temp, how many gallons per hour I am burning, my location when I run aground, my tracks, what fish are below me and the water temp

 

[alldodge]

My Garmin tells me the temp, how many gallons per hour I am burning, my location when I run aground, my tracks, what fish are below me and the water temp

Bet it don't tell ya how many beers are left in the cooler

 

[flashback]

I generally get in all at once, if I use the ladder I will probably wimp out.... just sayin..

 

[JimS123]

For me was to find out if it's warm enough to jump in

Buy a pool water temperature gauge. They are mercury, so very accurate. Plastic and only a couplabucks. Tie a string to one and and a lead sinker on the other end. Drop it in the water.

I have one in the glove compartment of my jetski. Works beautiful.

 

[alldodge]

Buy a pool water temperature gauge. They are mercury, so very accurate. Plastic and only a couplabucks. Tie a string to one and and a lead sinker on the other end. Drop it in the water.

I have one in the glove compartment of my jetski. Works beautiful.

Had one in my younger days. Like I really want bend down and wait, I'm old, not going to happen

 

[roscoe]

Bet it don't tell ya how many beers are left in the cooler

If you can still read the screen on the garmin, there are a few drinks left in the kesslers bottle.

If you can’t read the screen, the bottle is empty.

 

[JimS123]

Had one in my younger days. Like I really want bend down and wait, I'm old, not going to happen

If the string is long enough, and you wait till you open your beer you get an instant reading and no bending over.

Regardless, a boat is not your own unless you've drilled dozens of holes in it. You simply have to add a transducer and they all have temp.

 

[Scott Danforth]

If you can still read the screen on the garmin, there are a few drinks left in the kesslers bottle.

If you can’t read the screen, the bottle is empty.

LMAO.... Not to mention the door county cherry bounce

 

[mr 88]

Infra red temp gun from HF might be the easiest and cheapest way

 

[airshot]

Guess I am really old school here, I have always just stuck my arm in the water and if it feels good, I jump in, if to cold...I don't!

 

[Captain Caveman]

Well we still don't know why the OP wanted water temp.

1) Having a child around who is willing to jump into the lake is the cheapest/easiest test. The measurement unit is also easily replaceable.
2) Next is the thermometer on a string.
3) Cheap sonar is probably the best option.
4) Last in my mind would be to MacGyver something that may or may not work. If you're willing to go to that length in order to get temps, just work an extra day to get the cash to buy the sonar.

 

[JimS123]

Well we still don't know why the OP wanted water temp.

Yeah. That's an issue. Obviously, since he won't drill a hole for the normal Temp mount, he's kinda stuck without options.

 

[Augoose]

I was hesitant to drill into my hull as well. In 2013 or so (can't recall exactly) I mounted the sending unit of my fish finder to a 2"x2" square of cutting board and the epoxied the cutting board to my transom. As others suggested, I ran the wire up through an existing passthrough above the water line. 10 years later and hours and hours of skiing, wakeboarding, etc its still there.

 

[airshot]

I was hesitant to drill into my hull as well. In 2013 or so (can't recall exactly) I mounted the sending unit of my fish finder to a 2"x2" square of cutting board and the epoxied the cutting board to my transom. As others suggested, I ran the wire up through an existing passthrough above the water line. 10 years later and hours and hours of skiing, wakeboarding, etc its still there.

What material was the cutting board and what kind of epoxy? Curious minds would like to know!!

 

[Augoose]

Just a regular poly cutting board from Amazon (polyethylene?) and Loctite's marine epoxy. I doubled up the cutting board to make it thick enough for the length of the stainless screws that came with the transducer mount. Roughed up the mating surface of the cutting boards with a wood file, epoxied them together and let it set, mounted the transducer to the cutting board, again roughing up the mating surface of the cutting board against the transom and finally epoxied the cutting board to the transom. Other than cleaning the mating surfaces, I did not prep the fiberglass side at all. A bit of work and maybe unnecessary since folks drill into their transoms all the time but I like tinkering and enjoyed testing the limits of Loctite epoxy. Good stuff.
Did the same on my aluminum fishing boat.