how much fuel do you have when guage hits red.

[Nick_H]

So he should clean the tank if he's concerned, rather than only half empty it all the time. Filling up a boat is a PITA as there's usually a queue, so who'd want to do it twice as often as necessary, plus you severely limit your range if you're only prepared to half empty the tank. Also, you often get the diesel cheaper if you take more, so another reason to empty it each time.

To answer the original poster, it depends on your boat. My tanks are 1,400 litres each, and I can get 1,000 in when the guage shows 3/8 full. The red is at 1/8 full, so i'd expect to have very little fuel left once i'm in the red. Compare that to jfm, similar size and age of boat, and he has the opposite situation and runs into the red all the time, knowing he has plenty of fuel left.

 

[ian38_39]

Baffels wont stop the crud or if they do then you have been buying your fuel from all the wrong places and will run out of fuel with full tanks, well apart from the section with the pick up in and it wouldn't have got to that section unless the fuel filler hose is in the same bit.
The baffels are about 15mm to 25mm from the bottom of the tank just to stop the fuel sloshing from side to side.
If the tanks are full then there is a much lower concentration of dirty fuel and a bit of sloshing just mixes it up into floatation higher in the tanks, if the tanks are nearly empty there is no where for the crud to go other than up the pick up pipe.

 

[KevB]

We hold 550 ltrs and still have 200 litrs left when the gauge is in the red.

 

[Wiggo]

About the same. We have the much maligned plastic tanks and their redeeming feature is that you can see the fuel level in them, so I know that

full = full
2/3 = 3/4
1/2 = 2/3
1/3 = 1/2+
1/4 (start of red) = 1/3

So when I get just into the red, I know that I have maybe 350 litres, and even allowing for a 20% reserve on the tank capacity, that's still nearly 200litres of usable fuel, or 50 miles cruising.

 

[Stoaty]

I hardly ever see my gauge move. The tanks are 380 gallons together. The gauge is only for the reserve of 80 gallons, so mostly it reads 100%. I have sight gauges on the tanks to keep an eye on the non reserve level. When you burn less than a gallon an hour 80 gallons should easily give 500Nm range.

As for the should you fill them up or keep them low debate. My tanks are steel and I get a lot of condensation in them. Both filler caps always have water in them if you unscrew them and look into the cap. I have a regime of draining the sumps on the tanks on the first trip every month. When the tanks are full I can expect about half an egg cup full of water from each one. When the tanks are less than a third full I might get as much as a quarter pint each and summer seems to give more water as well.

I have a friend who has two 1000 litre plastic tanks and I have been impressed by how little (read virtually Zero) water he gets in his fuel. If it wasn't so much work I would swap to a plastic tank tomorrow.

 

[A_8]

My experiance is similar, when the gauge hits nill or the back end of the red I've still got 10% left.

 

[Renegade_Master]

Re: how much fuel do you have when gauge hits red.

Always keep a strict log, so each time I fill up start new log for that tank, have worked out the range based on average fuel consumption gleaned from monitoring several tank fill's, always allow at least a 25% reserve and dont go into it.