Big fuel tanks that are rarely baffled.
Most are an odd shape to fit the hull.
Ribs Bounce around a lot (If you are driving it the way you should).
The sender is a lever float or vertical float type that only gives a linear reading in a tank with parallel sides.
The height of fuel at the sender changes with the trim of the boat.
The sender terminals will constantly be exposed to Salt water.
The environment in which we use our boats will over time find its way up the wires insulation effecting the resistance of cables.
The fuel Gauge lives outside in all temperatures.
Etc.
As suggested by Nick, a dipstick if you have access is the only safe answer, particularly if your boat is more than a year old.
In your case i would check the floating piece of your sender inside your tank. Maybe it has come loose or got stuck.
In case of bad wiring it would not give half empty.
Try to empty (realy empty) your tank once a year to get the left water out.
This litlle amound of water sometimes gives rusty parts on the sender.
You could fit a fuel flow meter, this way you'll know how much you've used. The one on my Opti is surprisingly, very accurate, whereas the tank meter generally shows that I've got less fuel than what I actually have, which is no bad thing I suppose.
__________________ Steve G If In Doubt, Go Flat Out!!
I have just seen this featured in PBO. Pneumatic tank guage
It wont help with a shaped tank, but an interesting concept. www.sterling-power.com/
__________________ Mark H "A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools" Douglas Adams
