We use the smart craft Gauges .... and think they are great .... But fuel gauges on a boat are useless and should never be trusted , as there are two many variables that will alter the contents in the tank, and how the gauge reads. our tank sender wire is disconnected .
We use the 'fuel used' counter on the smart craft system, when we put in 100L we know that we are Ok until fuel used hits hits 100L (we allow 10% for error) and them we put in another 100L etc etc ...... we write down what we put in the tank ,on a water proof slate and check before we put to sea , I wouldn't leave the harbor unless I had 50L in the tank as a safety margin .....Just in case . we carry a spare 20L on the deck , in a portable petrol tank.
We have never run out of petrol , and if you do on a boat , you should hang your head in shame!!!!!!
Also the new suziki smart gauge system only records how much you are burning at any given moment , and doesn't record fuel used !!!!!
NOT THE SHARPEST KNIFE IN THE DRAWER