Thermometer recommendations or warnings?

[Allen42]

I'd like to get a thermometer to supplement my Datamax Pro Plus' internal thermometer. According the Oceanic's tech support, the computer's thermometer is fairly deep inside the console, and can take up to 15 minutes to provide an accurate reading of the temperature.

Well.... usually when I want to know the current temp, it's because I just dropped into a bone-jarring thermocline and I wanna know just how cold it is. I'd prefer not stick around (or follow it around as the case may be) for 15 minutes to find out the temp.

I've seen some $5 wrist-mounted thermometers, and the price just goes up from there for fancier, integrated into watches, etc. Any suggestions on a decent, fairly fast-acting, thermometer?

Thanks,
Allen

[DandyDon]

:cold: I know how you feel - as I went under the thermoclime at Catalina Island a year ago this month just long enough to know I didn't want to stay! My computer didn't register, so I don't know how cold...?

:frosty: Since then (you are welcome to laugh!) I paid a buck and a half for a plastic room thermometer at Walmart and tied it to my consel hose. Looks dumb, but works.

:thumb: Happy bubbles...!

[Allen42]

Dandydon, thanks.

I thought about doing the same, but had a couple of thoughts:

How deep have you taken this?

If it's mercury-based, I'm not sure how the pressure might affect its accuracy.


Your experience?

[DandyDon]

I've had it down 134 feet, and that's as deep as I ever plan to go at my age! :oldguy: And you won't find mercury in a consumer thermometer; haven't in decades, I don't think. Too dangerous and too expensive. I believe that liquid thermometers are all alcohol based. :boozer: There could be something wrong with the approach, but it's worked for the last dozen dives anyway.

And if it fails, the dollar fifty is one of my smaller diving expenses.
:jack:

Happy bubbles... :wavey:

[Allen42]

I didn't know that about alcohol replacing mercury. I should have said liquid-based versus bi-metallic type of thermometer.

I'm concerned that the changing ambient pressure might affect a liquid-based thermo, since I'm assuming the rest of the tube in the thermometer is filled with air which could compress somewhat, affecting the reading.

This is more academic than anything, since we're only talking about a $1.50 gadget, but it's interesting to me.

-Allen

[DA Aquamaster]

I used to use a little plastic or perhaps acrylic thermoneter designed to be attached to your ski jacket's zipper. It was actually molded quite thick and was very pressure resistant. The paper wind chill chart on the back lasted about a dive and a half, but the rest of the thermometer held up very well. (is there such a thing as "current chill" ?) It was eventually just glued to the back of a console. The reaction time for this thermometer was a couple minutes.

I also used a small bi-metal thermometer from US Divers that was designed to attached to a watch band. It also adjusted to ambient temp in a minute or two and with a little bending and crimping of the metal mounting tabs, found it's way onto the back of a console. My current dive computer has a thermometer with a fairly fast reaction time, so I no longer use a separate thermometer.

[DandyDon]

:oldguy: Just remembered. If you find 10 cheap thermometers for sale, it's likely that 7 or 8 will agree on the current temp, while 2 or 3 will be off. Pick one of the majority. No guarantee, just the good bet.

Happy Bubbles, :wave: Don

[pufferfish]

Here's the answer.
Trident sells the type of thermometer DA Aquamaster refers to. It is good to 200 feet and costs about $15 US. I have tried it and it works but I like the little one from www.innovativescuba.com better. At $6 it is a real steal!

[Allen42]

Pufferfish, I assume you're refering to the one that mounts onto a wristband and not the one integrated into the whistle, correct?

[pufferfish]

Yup the wristband one. All I can say is my buddy has one and his read the same (38F) so the precision seems good but don't know about the accuracy. Felt about that cold though :)

[DandyDon]

Ho, ho, ho...

Learned about a flaw in using the cheaper room thermometer when I worked with my reg oct today. Their held together with glue - which doens't hold up in saltwater. Duh?

I'm getting one like Pufferfish suggested. Thanks for starting the thread, so I could learn, too...!

D-Don :oldguy:

[DandyDon]

I bought one of the wristwatch mounted thermometes, and wore it on a dive trip to Catalina, however - when I looked down to see how cold it was below the second t-clime, it was gone! Sent it back to Divers Direct, but didn't hear from them. Called them today, and they're mailing me one. This time I'll spot weld it with super glue.

I tried supergluing a plastic thermometer so it wouldn't fall apart in saltwater for my next trip while I was waiting, but it broke. Myabe I'll tape one to the back of my slate?

[Matthew]

I've long wondered if there's something wrong with my computer's thermometer because the reading doesn't seem to vary much even when I feel really cold at depth. This could be the explanation - Ive gone shallower before the correct temp can register!
:D