cmedsailor
Well-Known Member
Is it a good practise to keep the fuel tank as full as possible all the time so to avoid water concentration (humidity?) or any other negative effects or it doesn't really matter?
Thanks
Thanks
Fuel tank - keep it completely full all the time?
- Thread starter cmedsailor
- Start date
Gin
Well-Known Member
Those who know about such things recommend that, as part of your winterising tactics, fuel tanks should be filled to the brim for the very reason you refer to so it follows, I suppose, that when leaving the boat for any time, it makes sense to do the same if practicable.
I don't know about you but I use very little of the stuff and I certainly can't be bothered topping the tank up even infrequently.
I don't know about you but I use very little of the stuff and I certainly can't be bothered topping the tank up even infrequently.
ytd
Well-Known Member
You'll get a few looks at the fuel dock when you buy 20l alongside a Mobo buying 2000l.
Gin
Well-Known Member
Too right. I have 2 x 13litre fuel cans which I refill once a season at a nearby garage selling red diesel, so I top up from those cans, which I keep at home, and it is a PITA as I always spill some on the deck.
I also keep another can as a spare on board but I've never used it and now after 3 seasons I know what my usage is, I shall take that off the boat this winter and free up a bit of locker space as I've never needed it
I also keep another can as a spare on board but I've never used it and now after 3 seasons I know what my usage is, I shall take that off the boat this winter and free up a bit of locker space as I've never needed it
alan
Well-Known Member
Gin, a bit off the original theme but FYI.
There is a "magic tube" with a valve in the end which can use to transfer fuel. They are on sale at most boat shows by a Dutch guy who has a small stand. In Italy there is a chandler that stocks them. You just stick the the end with the valve in the container, the other end in the filler hole on the boat, and "pump" it and down a few times to get the fuel flowing and bob's yer uncle. No more spilt fuel. Cost about €20 in Rome and worth every eurocent!!!!!!!!!!!!!!
Alan.
There is a "magic tube" with a valve in the end which can use to transfer fuel. They are on sale at most boat shows by a Dutch guy who has a small stand. In Italy there is a chandler that stocks them. You just stick the the end with the valve in the container, the other end in the filler hole on the boat, and "pump" it and down a few times to get the fuel flowing and bob's yer uncle. No more spilt fuel. Cost about €20 in Rome and worth every eurocent!!!!!!!!!!!!!!
Alan.
ctelfer38
Well-Known Member
No need to spend money on a valve thingy. Two pieces of tube - one longer than the other- one end of longer tube in the can the other end in the tank filler. One end of the shorter tube in the can also - the other end clean and ready to blow into. Cloth in hand - grip the two tubes at the can, sealing the can opening and give one short blow until fuel starts flowing through longer tube. Hands off and fuel will keep flowing through the longer tube and keep on doing so until can is empty. /forums/images/graemlins/cool.gif
Oldhand
Well-Known Member
Air in a fuel tank is as useful as runway behind you on take-off?.....
Twister_Ken
Well-Known Member
Beware of overfilling a tank, lest you get fuel escaping through the breather, and depositing itself in hard-to-clean places.
PeterGibbs
Well-Known Member
Trouble is that frequent filling increases the chances exponentially of overflowing fuel in the nice clean (hopefully!) briney. And spillage costs these days.
Is your tank metal or plastic? Condensation risks are much lower with plastic.
Winterwise - good practice to leave filled, reduces your contamination risks. And this year it will save on next year's fuel costs when they gallop up with taxation changes this November!
Fuel in cans - if left any length of time, you will notice it contaminates, goes mucky coloured and sludgy. So 20 Litres down the drain - you wouldn't risk putting that in your main tank!
Above all, you're out there for sun and fun. Friendly advice is to worry about something else, and take a relaxed view about saving your tank from contamination - it's one of the lesser risks in sailing! Changing your fuel filter at better intervals is arguably more to your advantage!
PWG
Is your tank metal or plastic? Condensation risks are much lower with plastic.
Winterwise - good practice to leave filled, reduces your contamination risks. And this year it will save on next year's fuel costs when they gallop up with taxation changes this November!
Fuel in cans - if left any length of time, you will notice it contaminates, goes mucky coloured and sludgy. So 20 Litres down the drain - you wouldn't risk putting that in your main tank!
Above all, you're out there for sun and fun. Friendly advice is to worry about something else, and take a relaxed view about saving your tank from contamination - it's one of the lesser risks in sailing! Changing your fuel filter at better intervals is arguably more to your advantage!
PWG
Petronella
Well-Known Member
In these days of rapidly escalating fuel prices it makes sense to keep topped up from a financial point of view too. Filling an empty tank before more tax is imposed on the fuel or before a significant general fuel increase takes affect can make quite a difference - especially from the end of one season to the start of the next.
John
John
santeana
Well-Known Member
Also leave small air space - maybe just the filler pipe - to allow for fuel expansion and to avoid consequential breather overflow.
tinkicker0
Well-Known Member
My old flying instructor always told me to top off the fuel tank at the end of the day to stop condensation forming in the tank. If the tank is steel it will also stop corrosion forming internally over winter.
To top up my boat, I have 2, 6 gallon outboard tanks fitted with self sealing valves and an outboard fuel tube with primer bulb.
Fuel can above boat tank.
Put the outlet end of the tube into the boat fuel tank, connect the two halves of the valve and if the petrol has built up a little pressure in the can, I dont even need to pump the bulb, the fuel flows by itself.
If not, a couple of pumps to start the siphon.
Empties a 6 gallon can in about 5 mins without spilling a drop or any fuel vapour in the bilge.
I do this whenever I go to the boat, even if not planning on taking a trip. This way the tank is always topped up and a reserve on board to top up post trip, although having 12 gallons in (ships wheel / CE approved) cans stowed away may not be the safest thing.
Never top up in the marina though. Hate my boat to catch fire and burn my neighbours.
Too mean to pay marina petrol prices. Priced at swindlery prices.
To top up my boat, I have 2, 6 gallon outboard tanks fitted with self sealing valves and an outboard fuel tube with primer bulb.
Fuel can above boat tank.
Put the outlet end of the tube into the boat fuel tank, connect the two halves of the valve and if the petrol has built up a little pressure in the can, I dont even need to pump the bulb, the fuel flows by itself.
If not, a couple of pumps to start the siphon.
Empties a 6 gallon can in about 5 mins without spilling a drop or any fuel vapour in the bilge.
I do this whenever I go to the boat, even if not planning on taking a trip. This way the tank is always topped up and a reserve on board to top up post trip, although having 12 gallons in (ships wheel / CE approved) cans stowed away may not be the safest thing.
Never top up in the marina though. Hate my boat to catch fire and burn my neighbours.
Too mean to pay marina petrol prices. Priced at swindlery prices.
1955patric
Well-Known Member
The reason for keeping the fuel tank as full as possible is to prevent the tank sweating. The air space in the tank will contain water vapour and this will condense out on cold surfaces i.e the tank walls, especially on steel tanks. A prerequiste for microbial contamination of fuel is the presence of water in the tank, either by sweating or being introduced into the tank when filling. The bugs live in the water and feed on the fuel at the fuel /water interface, so in order to minimise the chances of contamination all water needs to be excluded from the tank, and keeping your fuel tank topped up minimises the amount of sweating. Unfortunately, there is not much you can do about water in the supplier's fuel tank when you are taking on fuel so I always use a supplier who has a large turnover to minmise the risk of getting a slug of water
when fuelling up.
There are three types of bug and all of them are bad news.
For filter clogging, the worst culprit is a fungus which forms a mat at the interface but does not have any other detrimental effect - it just means you will have to keep changing/ cleaning the filter.
Worse are the bacterial infections. The aerobic bacteria form a jelly like substance which coats the bottom of the tank and can also cause filter problems, and also produces a mildly acidic solution which after some time can destroy fuel injection components.
Worst is the anaerobic bacteria which produces sulphur compounds as a by product of its metabolism. When these combine with the water in the base of the tank the result is sulphuric acid, which can be strong enough to rot the base of the tank right out and destroy your engine. Because they only thrive in anaerobic conditions, even stainless tanks will not survive for long.
It is worth almost any effort to minimise the chances of this happening.
We suffered from contamination on one ship I worked on a few years ago - engines ran on red diesel, and three months later when the tanks were sterilised and the fuel laundered, we had gone thorugh 900 fuel filter elements, 12 fuel, injection pump elements and 64 fuel injector nozzles. The bottoms of the fuel day tanks, made from 8mm mild steel were down to 2 - 3 mm thick in places and had to be replaced.
My advice would be to keep the tanks reasonably full if you can, and top up completely before laying the boat up for any length of time, especially in winter when tank sweating will be worst. Also try to obtain fuel from suppliers who have a large turnover to minimise the chances taking on contaminated or stale fuel.
when fuelling up.
There are three types of bug and all of them are bad news.
For filter clogging, the worst culprit is a fungus which forms a mat at the interface but does not have any other detrimental effect - it just means you will have to keep changing/ cleaning the filter.
Worse are the bacterial infections. The aerobic bacteria form a jelly like substance which coats the bottom of the tank and can also cause filter problems, and also produces a mildly acidic solution which after some time can destroy fuel injection components.
Worst is the anaerobic bacteria which produces sulphur compounds as a by product of its metabolism. When these combine with the water in the base of the tank the result is sulphuric acid, which can be strong enough to rot the base of the tank right out and destroy your engine. Because they only thrive in anaerobic conditions, even stainless tanks will not survive for long.
It is worth almost any effort to minimise the chances of this happening.
We suffered from contamination on one ship I worked on a few years ago - engines ran on red diesel, and three months later when the tanks were sterilised and the fuel laundered, we had gone thorugh 900 fuel filter elements, 12 fuel, injection pump elements and 64 fuel injector nozzles. The bottoms of the fuel day tanks, made from 8mm mild steel were down to 2 - 3 mm thick in places and had to be replaced.
My advice would be to keep the tanks reasonably full if you can, and top up completely before laying the boat up for any length of time, especially in winter when tank sweating will be worst. Also try to obtain fuel from suppliers who have a large turnover to minimise the chances taking on contaminated or stale fuel.
santeana
Well-Known Member
Neat idea - for 5/8 vent. Thanks.
Gin
Well-Known Member
Alan,
I have got one of those and I tested at the boat jumble and at home to ensure i could use it, and it seemd OK.
I tried it out before I launched this year and your post has just reminded me that I struggled to get it to syphon and I remember now that I brought it home to practice again- which of course I've forgotten to do.
Must try again, thanks for kickstaring the memory!
I have got one of those and I tested at the boat jumble and at home to ensure i could use it, and it seemd OK.
I tried it out before I launched this year and your post has just reminded me that I struggled to get it to syphon and I remember now that I brought it home to practice again- which of course I've forgotten to do.
Must try again, thanks for kickstaring the memory!
brianhumber
Well-Known Member
As far as possible yes. General rule has been this helps starve the pesky bugs. As one other poster has said bugs can be a real pain. I know some swear nowadays by dosing to kill 'em off but my employer drummed into us when I was a young engineer that using prevention always was better than a cure. /forums/images/graemlins/grin.gif
Brian
Brian
fishermantwo
Well-Known Member
[ QUOTE ]
My old flying instructor always told me to top off the fuel tank at the end of the day to stop condensation forming in the tank.
[/ QUOTE ]
This was because of the fumes above high octane fuel make for a big bomb. The fuel is not the dangerous part. Think of an aircraft carrier hangar full of aircraft, they have to have full tanks to make them safer.
My old flying instructor always told me to top off the fuel tank at the end of the day to stop condensation forming in the tank.
[/ QUOTE ]
This was because of the fumes above high octane fuel make for a big bomb. The fuel is not the dangerous part. Think of an aircraft carrier hangar full of aircraft, they have to have full tanks to make them safer.
tinkicker0
Well-Known Member
>This was because of the fumes above high octane fuel make for a big bomb. The fuel is not the dangerous part. Think of an aircraft carrier hangar full of aircraft, they have to have full tanks to make them safer. <
Err No.
It was because the tanks on many light aircraft are bladders laid in the wings.
These develop wrinkles over time and trap water in them. you can do a water test in the preflight and find nothing, then during flight manouvres, the water gets into the fuel system and fills the carb.
Not good at 6000 feet over mountainous terrain.
Err No.
It was because the tanks on many light aircraft are bladders laid in the wings.
These develop wrinkles over time and trap water in them. you can do a water test in the preflight and find nothing, then during flight manouvres, the water gets into the fuel system and fills the carb.
Not good at 6000 feet over mountainous terrain.