Winter Lay-up - New Zealand Conditions

To fuel or not to fuel

 

So, it’s come round to Autumn and everyone is thinking of storing their boat - but what are you going to do about all that costly diesel in the fuel tank?

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

For decades, the general consensus was to fill the fuel tank to 100% capacity in an effort to minimise the exposed tank area above the fuel level, which could lead to condensation. This condensation would sink and settle as water at the bottom of the tank, visible beneath the diesel, thereby increasing the risk of diesel bug proliferation.

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 day's cruising, only to find all the dead diesel bug and their excrement stirring up from the bottom of the tank the moment you hit the breakwater, blocking the filters, stopping the engine, and certainly ruining your day. Even more so if you have to call out the Coastguard; we hear this scenario a lot.

So why don’t we suggest filling the tank up any longer?

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

Modern diesel is highly unstable; it’s been refined to remove almost all the sulphur.

It degrades rapidly, forming sludge that settles at the bottom of your tank.

The stability improver and antioxidant we blend into Marine 16 Diesel Fuel Complete (DFC) helps slow down some of the degradation - but it cannot be stopped!

Here at Marine 16, we advise running the fuel tank down to as near empty as possible. Remove as much water as you can, if possible, and add a kill dose of Diesel Bug Treatment (DBT) to eliminate any bugs that might seek refuge in your tank during lay-up. You can prevent moisture from entering the tank by fitting a desiccant breather on the vent. This will dry the air as it is drawn into the tank, preventing condensation on the sides.

Additionally, add a dose of Diesel Fuel Complete (DFC), even if you have been using it. Based on our research with fuel testing laboratories, we have enhanced DFC with an additional antioxidant in the blend to help reduce ongoing FAME (the bio component in diesel) degradation, which leads to the formation of carboxylate acids.

We can’t prevent the degradation, but along with the dispersant in the blend, this will help reduce deposit formation at the bottom of the tank.

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