Fuel Storage when Laying up you boat for long periods of time.

So it’s come around to Autumn and everyone is thinking of laying up their boat for the winter – what you are going to do? fill up your tank with expensive diesel?

First off, DON’T TOP UP YOUR FUEL TANK… here’s why.

The rules have changed.

For decades the general consensus was to fill the fuel tank 100% full in an effort to reduce as much as possible the exposed tank area above the level of fuel which gave rise to condensation that would sink and lie as free water on the bottom of the tank, that’s the water you can see under the diesel, so leading to the very real potential for diesel bug contamination to proliferate.

So topping up the tank made a lot of sense given that diesel bug live in water and like all bacteria, double their number every twenty minutes!

You could return in the spring, fire up the engine and head out for a days cruising only then to find all the dead diesel bug and their excrement stirring up from the bottom of the tank the minute you hit the breakwater, blocking the filters, stopping the engine and certainly ruining your day. Even more so if you have to call out RCR or RNLI, we hear this scenario a lot.

So why don’t we recommend topping the tank up any more?

All the oil majors collectively agree you should not store diesel longer than 6 months but lets face it that is totally impractical on a boat. Especially given the time it takes to get to you, the end user, it is often up to 2 months old anyway.

Both Red and white Modern diesel is highly unstable, it’s been refined to within an inch of it’s life to remove the Sulphur and now has min 7% plant oil along with animal and cooking fats.

It degrades very quickly producing sludge that ends up on the bottom of your tank.

The stability improver and antioxidant blended into Marine 16 Diesel Fuel Complete (DFC) additives helps slow some of the degradation – but it cannot be stopped!