With the new diesel heater project it came to the discussion table that our fuel needs would increase during winter and the thought of carting jerrycans of fuel (we didn’t want to connect the diesel heater to the existing engine tanks) in the cold and possible wet days of winter is something none of us could look forward too.
At the same time, we were about to visit Montenegro where we could top up on duty-free fuel on our departure (price in June 2019 was 0.64€ per litre). With the knowledge that there are a few other places in the Mediterranean (Gibraltar, Morocco, Tunisia) with fuel prices more attractive than the current price of around 1.30€ a litre of most Southern European countries the idea that we could benefit of increasing our fuel capacity started growing in the back of our minds.
Originally The Dream, a 2013 Dufour 500GL was fitted with 500 Litres of diesel and on top of that we carry 100 Litres of emergency fuel in jerrycans but the possibility of expanding our capacity meant not only a good savings opportunity when we crossed with better fuel prices but also our off the beaten track range would increase exponentially. With our plans for the future, that idea was becoming more and more attractive.
The decision was made, we were going to install another fuel tank, we just needed to see what capacity we could fit on the stern deep locker.
We decided on a 140 Litres model that would fit quite well centred on the available space and we could install a normal fuel inlet next to one of the existing ones, adding a new vent wouldn’t be a problem also.
The 140 Litres of diesel should provide 280 hours of heat at full output according to the diesel heater fuel consumption data but we are very unlikely to use that much over the winter so this new tank besides supplying the diesel heater would become a backup/long-range engine tank.
With the new tank fitted just like one of the original tanks, we could take full advantage of duty free fuel (it’s not possible to fill jerrycans when getting duty free fuel and a lot of the Marina fuel docks don’t fill them also) without any problem.
For a while we debated on how to connect it to the engine, should we add a new fuel intake to the existing system, should we connect the new tank to one of the existing tanks or should we leave it completely isolated (only connected to the diesel heater)?
We ended up deciding we would leave the tank isolated from the existing tanks and make use of a fuel transfer pump, allowing us this way to choose which tank we want to transfer the fuel into and also allowing us to transfer fuel to the emergency jerrycans and make space for more fuel at good prices when going to the fuel dock.
There was another reason behind this decision, with our history with fuel bug this would allow us more options in case of problems.
After a bit of work fitting the diesel heater in the deep stern locker and then installing the new diesel tank The Dream fuel capacity is now 640 Litres plus 100 Litres on emergency jerrycans and that allows us around a 1000 Nautical Miles range!