The water injection elbows on the exhausts of Wind Horse’s engines and genset are fitted with temperature sensing bands supplied by AquaAlarm. If these exceed a preset temperature they close a circuit which triggers an alarm. In theory, this is an early warning of salt water flow failure. We are also fitted with sensors on the water flow itself upstream of the engines. None of these devices has ever given us a warning signal.

Last week the genset exhaust alarm went off. We checked the transom and there appeared to be good water flow, and the gauges did not indicate higher than normal temperature. We shut down the genset, the alarm reset, and we started the genset without problem.

When this happened again two days later, with the same operating conditions, we assumed a faulty sensor, and loosened the band.

Shortly thereafter we moved the boat 30 miles. This was  our first “passage” in several weeks. The engine exhausts sounded slightly different, but we chalked this up to our not being used to the frequency after sitting so long.

An hour later we were in the engine room doing our usual check underway. The watermaker had tripped off on low feed water pressure, usually a sign of a dirty filter. But we could see it was clean. The remote temperature sensing gun showed normal on all the usual places. Steve happened to brush against the starboard engine Aqualift in the exhaust line and it felt warmer than usual. Water flow from the exhaust out the transom seemed robust. But just in case we shut down both engines to check the strainers and… both were totally plugged with weed.

The engine pumps had the muscle to pull through the weed but the genset obviously was not getting sufficient flow for cooling for the exhaust.

Net time we get an alarm like this we’ll pay closer attention!