I need a strap on temperature alarm thingy

Rivers & creeks

Rivers & creeks

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The temperature gauge on the engine only measures the coolant temp and has no alarm. I would like to fit an exhaust overheat alarm and I'm sure I saw one a while ago that you strapped around the exhaust. It gives immediate notification of a loss of coolant. We have a fresh water cooled Thornycroft 75hp. Any suggestions or links? I've googled boat temperature alarm, boat exhaust alarm etc. thanks.
 
Halyard marine do the one that I have.
The sensor used to be a lollipop stick thing that fitted down the flexi-exhaust, a bit like a dirk down a Scotsman's sock. The later ones do fix on the outside.
They are expensive though. See here:

http://www.halyard.eu.com/Products/exhaust_alert.html

I have seen much cheaper solutions suggested on here. Maybe someone will chip in a moment.

PS,

Nope I was wrong, I remember now. When I changed the sensor I had to drill a hole in the exhaust hose to fit the new one.
 
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Thanks for that. The search feature on YBW drives me mad "exhaust temperature alarm" throws up every post with any of those three words in. The cheapest seems to be £76 and on eBay.
 
FWIW.. I went down this route and ended up installing a probe that inserts into the exhaust hose.. I felt it was the best way to record an immediate temperature rise...

http://www.asap-supplies.com/marine.../vetus-temperature-sender-hose-mounted-413158

I know it's expensive but I didn't spend money on the Vetus display unit.. I just wired it into the water temp alarm.. so same buzzer in cockpit goes off for either water or exhaust temp alert..
 
We use this sort of thing. http://www.weather-station-products.co.uk/minmax-thermometer-with-probe. We have the external probe clipped to the outside of the exhaust just where the engine seawater is injected. The display is the cockpit. After a bit of trial and error with the position of the probe we have found a position that stays at less than 40 deg C with normal running and the temp shoots up if the seawater flow is constricted (response takes about 20-40 seconds).

Cheap enough to carry a couple of spares.
 
I made an exhaust temperature alarm with one of these

http://uk.rs-online.com/web/search/s...duct&R=331-562

jubilee clipped to the hot part of the exhaust

and one of these:

http://uk.rs-online.com/web/search/s...uct&R=617-3097

for under a tenner.

I have evidence that it works. In truth is cost me a little more because I worked up the sensors from 70 degress until I reached a level that didn't trip at normal usage temperatures.

In truth I didn't invent it - someone else posted the idea on the forum, but I can't find the original post.
 
dovekie said:
We use this sort of thing. http://www.weather-station-products.co.uk/minmax-thermometer-with-probe. We have the external probe clipped to the outside of the exhaust just where the engine seawater is injected. The display is the cockpit. After a bit of trial and error with the position of the probe we have found a position that stays at less than 40 deg C with normal running and the temp shoots up if the seawater flow is constricted (response takes about 20-40 seconds).

Cheap enough to carry a couple of spares.
Click to expand...

Thanks - that's so left field - it's inspired! Like you say, easy install or carry a couple of them.

Amulet said:
I made an exhaust temperature alarm with one of these

http://uk.rs-online.com/web/search/s...duct&R=331-562

jubilee clipped to the hot part of the exhaust

and one of these:

http://uk.rs-online.com/web/search/s...uct&R=617-3097

for under a tenner.

I have evidence that it works. In truth is cost me a little more because I worked up the sensors from 70 degress until I reached a level that didn't trip at normal usage temperatures.

In truth I didn't invent it - someone else posted the idea on the forum, but I can't find the original post.
Click to expand...

I get broken links on both those web pages - is it me?
 
Bought these parts from http://www.rapidonline.com ;

Theremal switch - closes at 90 deg C
piezo siren
test switch

Sited the thermal switch just after the cooling water injection on the exhaust and secured it with thermal paste and wire.
Took a feed from the ignition switch so that the alarm is live when the ignition is on, wired the thermal switch and test switch in parallel and put the piezo siren in the line to the negative. This is the pbo design and is really simple and easy to do (and cheap). How effective it is I don't know as the boat hasn't gone in yet but I'll be giving it a test when it has.

I guess the more expensive kits are probably better (the ones that go through the hose looks good) but I see no reason why the simple one should not work.
 
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