Living the dream
The original alternator driven tacho/hourmeter on my boat never worked properly. Replaced it with a not inexpensive alternator driven digital tachometer/hourmeter with analogue display and it doesn't work properly either. Not sure if faulty or if there's something wrong with my alternator. I have contemplated the idea of a second tacho at the helm too, because the engine control is in the cabin and my thoughts now are if I do this to definitely use a magnetic / optical pickup variant to eliminate problems that may be caused by the alternator. I did purchase a cheap non contact tachometer off Ebay and use it to calibrate, or rather attempt to calibrate, the new tachometer. At the moment I set engine revs by sound and throttle position, but the tool remains on the boat allowing me to do spot checks if needed.