Fuel Tank dilemma

[CliveG]

Sirenia ( 25 ft lift keel with 10 hp Beta inboard) has a 5.5 gallon Aluminium fuel tank fitted in the cockpit locker.
This is not big enough as far as I am concerned.
This gives about 10 hrs endurance at most
I would like at least 30 hours
Our continental cousins do not like us carrying red diesel from the UK in portable containers only in the boats fuel tank.

I have 3 options:-

Get the tank enlarged.
A friend has a company the employs an aluminium welder so this should not be to hard to sort.

Fit an extra tank with about 11 gallon capacity
A plastic tank I think.
It would be fitted directly above the existing tank
This could be plumbed in two ways.
Cut into the existing filling pipe so that the engine pipe work stays connected to the existing tank
Or plumbed separately with some change over valves for the flow and return.

Any comments on these options
Any other suggestions.

 

[lw395]

Change over valves would have the advantage of keeping a reserve of clean diesel if you happened to buy some dirty diesel. But running onto reserve could involve bleeding the system. Personally I have a big tank plus a few gallons in a can, which I will pay the french duty on if they ever ask... Probably cheaper than fancy plumbing, if possibly more hassle.
But then our endurance is limited by me not wanting to hear
the engine for more than an hour if it can be reasonably avoided. perhaps the ideal would be dual tanks with separate primary filters and something to warn of first tank running out?
Cheers,
Chris

 

[bazobeleza]

I'd go for an additional separate poly tank with its own filter / watertrap and stop cock so you always have a clean supply of diesel in case of contanimation plumbed in so you can change filters on the move if necessary. this also alows flexibility in draining tanks for cleaning etc Twin tanks and twin filters have saved the day for me when water got into the stbd tank in rough seas, enabling me to switch tanks, change wet filter all without stopping the engine or even slowing down

 

[photodog]

Have you thought about how the additional weight of the fuel in this location will affect the trim of the boat...
might be better to spread the weight around abit by locating a seond tank elsewere, or simply using gerry cans.

30 gallons on 25footer seems an awfull large amount of fuel to carry! Certainly nearly 3 times what we carry, and I can do a 2 or 3 week cruise on one tank!

/forums/images/graemlins/smile.gif

 

[Talbot]

your arithmetic is a bit suspect - he talks about 30 hours endurance which is nearer to 15 gallons = 150 lb

 

[photodog]

doh! Not so much my maths, more my reading/comprehension skills....

/forums/images/graemlins/smile.gif

 

[FullCircle]

Talbot...
Nearer 100lbs surely?
8 pints in a gallon, each pint just short of a pound, so about 7 and a bit pounds a gallon?


Anyway. Clive: Beta 10 should be doing over 3 hours on a gallon, my 30hp Yanmar does 2 hours at cruise 5.5kts to the gallon, so really 10 gallons is realistic.
In the space you have in the Evo, there is plenty of room for a replacement 10 gallon
around 75 quid in Eltex.

http://www.imsupplies.co.uk/product.php?productid=992&cat=73&page=3

 

[Leighb]

Water weighs 10lbs/gallon, petrol 8lbs/gallon.
Remember the old rhyme.
"A pint of pure water weighs a pound and a quarter"

I guess diesel is a little denser than petrol, so perhaps around 125lbs for 15 gallons.

 

[Bejasus]

[ QUOTE ]
I guess diesel is a little denser than petrol, so perhaps around 125lbs for 15 gallons.

[/ QUOTE ]
122.5lbs/15gal /forums/images/graemlins/smile.gif

 

[JackFrobisher]

Apropos of going foreign and the duty on red, just carry white. The actual difference in cost for a trip across the water is quite small.

 

[Talbot]

[ QUOTE ]
Talbot...
Nearer 100lbs surely?
8 pints in a gallon, each pint just short of a pound, so about 7 and a bit pounds a gallon?around 75 quid in Eltex.

[/ QUOTE ]

I was adding in weight for the tank!

 

[ditchcrawler]

As Full Circ says are you sure your consumption is correct.My 28HP Volvo averages about 1.4 litres per hour & when I had a 1GM10(9HP) this did 1 litre per hour.Your 25 litre tank should give you at least 20 hrs I would have thought.

 

[CliveG]

Hi

The documentation for the engine give a consumption figure of 2.5 ltr/hr at full revs On our Oostend trip last year we used about 3 gallons on 9 hours.
That is about 1.5 ltrs/hr.
I don't want to get to close to the bottom of the tank at sea.

I did let the tank get quite low on weekend last year and than had to use the engine in some rough water and managed to block the fuel filter with sediment from the tank.

I would like some reserve.

1.5 ltr/hr for 30 hours is 45 ltrs or 10 gallons.
I would like at least 2 gallons in reserve.
I think that I will try to get the existing tank enlarged 1st.

 

[conolan]

I have a Bukh 8hp engine and reckon it uses less than a litre per hour. So agree with others above that you may have more range than you think (you don't do full revs do you?).
Rarely bother with red diesel. Quicker to buy white in a petrol station than try to find out where I can get red in unfamiliar places. Always have reserve in a jerrycan.
I'd be inclined not to mess around with the tank unless you think it needs to be replaced.