For the last few weeks, we were unable to see our speed displayed. Craig checked all the wiring and assorted Raymarine codes and all were fine. That led us to believe that the problem was in the actual transducer and it needed to be cleaned. Who knew how nerve wracking it would be to open up a hole in the boat and have water surge through it in a geyser. We now know that feeling…but at least it was a controlled geyser. Now our knot meter is working and all is good. We videoed the cleaning, see below.