When having two of everything helps
As a follow up to my post about fuel gauge senders, I ultimately determined that the issue lies with the gauge at the helm, not the sender itself.
A seldom discussed benefit of catamarans is that most often we have two of each mechanical item, allowing us to swap one for another during troubleshooting exercises. I have found this to be extremely helpful. In this case, after ruling out the senders as the source of the trouble, I simply swapped the gauges. Voila! Now the port side tank reads full, as it should.
Testing the sender with a multimeter.
Quick clip recorded on our iPhone.
In our particular case, until we get a replacement gauge, it’s more important that I have the proper reading for the port tank than the starboard one as it feeds both the engine and the generator. Because of that, it always goes down faster than the starboard tank.
A bit of advice for anyone shopping for a replacement gauge: make sure that the resistance rating of the gauge matches that of the sender. While I found VDO brand gauges in stock here on the island, none of them properly matched the ones on the boat.