About five years ago we were visited by another cruiser at Catalina Island, and he mentioned a remote temperature sensing "gun". He used it to check his engine and drive line, and for chasing electrical problems. It sounded like a great idea, so we picked one up.

We used this periodically on Beowulf, but did not really put it to work until Wind Horse. There are a variety of these now on the market, ranging in price from under fifty dollars (US) to several hundred dollars. They typically work on the same approach - a laser dot (you can see the red dot by the fridge door handle above) shows you the point at which temperature is sensed. The unit then gives you this data in Fahrenheit or Celsius. Our model will also display the maximum reading.

In the engine room, we use this to check cylinder temperatures - if they are all firing the same, their temperatures will be similar. The same check can be made on the exhaust manifold at each cylinder. We also use it on the turbo air intakes, alternators, fuel supply, CV axles, engine heat exchangers, alternator diodes, and hydraulic pressure pumps. At least once per watch we give everything a quick check.

These guns are also helpful with the fridge box (looking for gasket or insulation leakage) with air conditioning, to check battery temperature, and to even check hull temperature. You can find a loose electrical connection because it will be warmer than tighter connections, and check wiring for correct sizing (if it is too warm, you know the loads are higher than should be the case for a wire of that size.

Now that we're used to this little device, it would be hard to go back to the old-fashioned system of checking heat by hand.