Tag: Blue Opal
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Sending engine RPMs to the NMEA bus, 2/x
It turns out that iNavX doesn’t support rendering ERRPM; it only supports the NMEA 2000 variant, PGN 127488. This led me down the path of trying to work out if I could send PGNs to the MiniPlex3 via the WiFi interface. The answer is sort of yes – you can send a specially crafted 0183…
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Sending engine RPMs to the NMEA bus, 1/x
Whilst Dad was visiting, we put his portable oscilloscope across the two terminals on the back of the tachometer, and found a very nice mV signal that changes frequency with engine revolutions. This means that a bit of circuitry plus a microcontroller will enable me to push the rev count to the boat data network.…
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Finding the right cable size for the water pump
Given the voltage drop at the pump, yesterday evening’s project was to wire the pump with 8 AWG (10mm sq) for the positive feed, and a bit of 2 AWG (35mm sq) for the negative feed. Unsurprisingly, the pump worked very happily, and the clamp ammeter gave me glimpse of ~10 – 11 amps of…
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Reconnecting the GPS
A casualty of the wiring locker re-wire was the GPS connection for the Raymarine Autohelm system. The previous install was temporary, and used two chocolate blocks to bridge the three wires for the ground. The existing cable to the GPS uses red (+12V), yellow (data), and black (power ground and signal ground). The Raymarine gear…
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Wanted: non-paddlewheel speed log that doesn’t break the bank
In a recent post, I mentioned wanting to replace the paddle wheel on Blue Opal with something that isn’t a paddle wheel. The two options appear to be ultrasonic and electromagnetic. On the ultrasonic front, the main contenders appear to be nke and AIRMAR. On the electromagnetic front, nke show up again, as do NASA…
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More anodes, and a quick hull clean
When Blue Opal was launched back in April, the yard in Pwlhelli had installed a cone-type anode on the end of the prop for me. With Blue Opal on the slip this weekend gone, I figured it was worth checking that the anode was still present. Spoiler, it wasn’t. A quick visit to the local…