How do I know if my boat’s fuel gauge is reading right?
Check it against the pump. At your next fill, note the gauge before and after, and the litres the pump says went in. If the two disagree, it is the gauge that is wrong.
At Bermagui on 19 September 2026, Shimbiri’s port diesel tank took 162 litres at the pump while its gauge rose 129. The Chief Engineer flagged it: either the tank is larger than its profile says, or the sender reads low.
So keep a fuel log: litres in, engine hours and the gauge at every fill. Shimbiri keeps it for you, and measures the burn per engine hour from your own fills. Then carry the reserve: MAST Tasmania recommends the rule of thirds, one third of your fuel for the way out, one third for the return and one third in reserve.
The Chief Engineer compares the litres the pump put in with what each tank sender showed, records each fill with its engine hours, and measures burn per engine hour from the fills.
General information for Australian operators, current as of 6 October 2026. Rules change and recreational rules vary by state. Always confirm against the source(s) linked above (your AMSA, Australian Sailing or state maritime authority). This is not legal advice.