Is it good prcatice to fill up fuel tanks despite not needing to?

Thepipdoc

Thepipdoc

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Just returned from a 3 week trip to Guernsey, Jersey and various ports in northern France and I now have about 2/3rds of fuel on board.
Even though I'm not planning any long trips over the next few months, or for that matter over the winter period, should I fill both fuel tanks up now? Is this good practice or am I just storing diesel that will "go off"?
(fuel capacity approx 720 litres).

I will be using the boat every weekend but the engines will use only a very small amount of juice on each trip from the swinging mooring to the local town/s, Dartmouth and Totnes. The fuel I currently have is easily enough to see me right through the winter and into spring.
 
It is always best to keep the tanks full especially in the winter months as it helps to prevent condensation from forming on the empty part of the tanks and then running to the bottom to eventually give you the dreaded diesel bug.....
 
I know the accepted wisdom is to keep tanks full to reduce condensation, especially over winter if the boat is out of commission, but I've never done it in 20yrs and never had a problem the following spring. The other way to look at it is that if you are constantly topping up your tanks, you are always carrying extra weight around which will reduce performance and increase fuel consumption.
In your case, you plan to use your boat regularly at weekends so I wouldn't worry about it.
 
My understanding is to fill the diesel tank for the winter, as others have said to reduce the surface area above the fuel, which will ocndensate in the winter, introducing water into the tank, and creating the opportunity for the dreaded bug.
 
I'm with Deleted User

for most planning craft the best solution is to cruise with the minimum necessary to get you safely to the next fueling situation (safety, convenience etc all applying).

many don't have a lot of scope in this and just fill up.

winter storage, especially on the hard, is worthy of filling the tanks to avoid the build up of condensation and the resultant water sitting in the tanks for months as a breeding ground for micro-organisms.

personally I have large enough tanks to provide a degree of choice over where I fill up - so I don't leave St PP other than full!
 
Does diesel have a shelf life ? I was running low last week. Consoled myself that in an emergency there was a 10 litre can on board but then calculated that this must have been in locker since 2008 so presumably, like petrol it deterioates , and could have been very unhelpful to try and use ?
 
skua said:
Does diesel have a shelf life ? I was running low last week. Consoled myself that in an emergency there was a 10 litre can on board but then calculated that this must have been in locker since 2008 so presumably, like petrol it deterioates , and could have been very unhelpful to try and use ?
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No, petrol will go off, but diesel has a much longer shelf life. There are diesel dumps all over the country in the event of war.
 
since January this year red diesel now has a percentage of bio fuel in it, this will breakdown in your fuel tank after 3 months, there are addatives on the market that will prolong its shelf life, I use a product called exocet fuel save. I always keep my tanks full and most definetley make sure they are full to the brim in the winter, it saves the build up of condensation in the tank.
 
PRH said:
It is always best to keep the tanks full especially in the winter months as it helps to prevent condensation from forming on the empty part of the tanks and then running to the bottom to eventually give you the dreaded diesel bug.....
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I have read this many many times on the internet and the conclusion i have come to is that full or empty make no difference, i have had mine at both and never had an issue. There is also the arguement of fuel going stale, again i have never experienced it, untill a few months ago i had my generator sat outdoors for a few years, it started 1st time and ran all day untill i had to top up again.
 
My personal preference after a long passage is to always fill on arriving at a new ports. Reasons:
  • Leaves max options open when departing (eg weather diversions to non fuel locations)
  • Avoids delay on day of departure (eg no waiting for fuel truck)
  • During winter reduces water buildup in tanks
Last winter we left our boat in the water, tanks 80% full. BUT, the combination of an exceptionally cold winter combined with decent heating on to avoid frost damage caused very significant condensation buildup (ie warm boat, cold tank filler necks). We drained 6 liters of water from each tank in the spring. There was none in the tanks the previous autumn. Admittedly last winter was exceptional as this did not happen on previous years.
 
Whatever best practise used to be I think it is now to keep them as empty as possible if you have white diesel with FAME added in your tanks.
 
A_8 said:
Whatever best practise used to be I think it is now to keep them as empty as possible if you have white diesel with FAME added in your tanks.
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As well as driving trucks, I occasionally do some cash work driving the bigger combine harvesters, usually Claas machines. Yesterday I was at the maintenance yard of one of the big local contractors. I mentioned the problem of red diesel +bio to him, and he showed me the new layup procedures for Claas machines.

Firstly FYI modern combines are normally laid up in October, and re-awakened in May, so nearly seven months. The basic procedure which has just been issued as urgent, assumes all red diesel will have some bio content.

After some preamble describing the problems this is causing, the interim procedure is:-

All fuel to be drained from the tanks.

Feed and return fuel lines to be disconnected at the tank, and the injector pump and blown through with compressed air to remove and remaining fuel.

Both in-line fuel filter cartridges to be removed and discarded and replaced with Claas cartridges designed for layup (Silica Gel thing's). Ends of fuel lines to be plugged with another claas part (basically plastic plugs)

Fuel tank water trap to be removed blown through with compressed air and dried. The fuel tank filler to be replaced with a silica gel cap. The fuel drain cock is to be left open but covered with gauze to prevent ingress of insects.

ADDITIVES (Mandatory)

When in service Claas fuel additive must be added at the rate of .5 litres per 350litre tankful to ensure adequate lubrication of injectors and pump. This additive also dissolves any water or flocullant in the fuel to pass through the fuel system without damage.

There are then dire warnings about warranty limitations if you don't follow this procedure.

SO I know the above is purely agricultural but seems we are not the only ones who have problems, makes for a lot of work and expense at both ends of the season though.

(Stolen from another forum - please don't shoot me!!)
 
Winterising your boat

If that is the case ...Bio Fuel in red diesel you will have to lay your boat engine up the same way.as the winter lay up is 6 months..the other way is run your engines up in the winter every month...easy if your vessel is on a mooring but you will have to remove all raw water Jabsco pump impellors if your are on the hard and only run engines for a short time and not up to working temperature,that should keep fresh fuel flowing through the system...this is only if the life of the fuel can be extended to a 6 month period if is not then you will have drain the system.....this is does not seem real progress..or has not been fully thought through unless you are a marine engineer and it could be a real bonus....:rolleyes:
 
I was told (and my Sealine manuals states this as well) by a marine engineer to keep my tanks full during winter as keeping them empty over long periods of time (winter being the biggest culprit) can cause condensation build up in the tanks however you can buy a chemical to dissolve the water in diesel which is called aquasolve.

Never used it myself.
 
As i said earlier it would seem there is no better way, personally i would fill them as the cost is only going one way and in the new season you have a full tank to burn off having fun ;)
 
The issue is not the diesel, its the bio element, this is actually biodegradeable and will rapidly break down if water is introduced into the equation.

The only safe option is to keep the tanks full as this reduces the condensation from forming in the first place, basically its insurance.
 
Assassin said:
The issue is not the diesel, its the bio element, this is actually biodegradeable and will rapidly break down if water is introduced into the equation.

The only safe option is to keep the tanks full as this reduces the condensation from forming in the first place, basically its insurance.
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This is my understanding too.
 
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