Tam Lin
Well-Known Member
What are the chances of even having the boat in ten or twenty years time?
When I cleaned my tank I managed OK with using the filler pipe.
Replacing a fuel tank
- Thread starter Jokani
- Start date
What are the chances of even having the boat in ten or twenty years time?
When I cleaned my tank I managed OK with using the filler pipe.
sarabande
Well-Known Member
every time you fill up, you risk the bug being there, unless the dosing regime is faultless. And we are all too familiar nowadays with the effect of biodiesel in bug promotion.
I think the consumption cycle and diesel return will mitigate against any bacterial development in a new and well managed tank, but a couple of really warm weeks in summer, with the boat not used, could alter that.
Prevention less expensive than cure, perhaps ?
rogerthebodger
Well-Known Member
As I said " I would incorporate a large bolt on hatch" You seem to disagree so lets just agree to disagree.
After I posted I noted the OP did include an inspection hatch on his sketch so my comment had been included by the OP.
My diesel tanks are much larger then the OP and I have access hatches in all 3 tanks. I have also had the need to get inside my tanks to fix a level float switch to alarm when the tank is getting full. The float switch helps prevent the tank overflowing and thus causing pollution by diesel in the sea.
pvb
Well-Known Member
If the top of the tank was easily accessible, I'd have no problem with having an inspection hatch. It's simply that the OP's tank is shoe-horned in to a space right under the cockpit and so would have to be removed completely to use an inspection hatch. With such a small tank, if you've removed it completely it would be perfectly feasible to clean it via the filler hole. This is a Practical Boat Owner forum, and my comment is all about practicality.
rogerthebodger
Well-Known Member
A friend of mine was rebuilding a Nauticat had the diesel tanks right up under the deck head so like the OP no point in having an access hatch on the top of the tank but the original fitted tanks had access hatched in the side.
This would not be my favorite way of fitting access hatches but allow anyone to get inside once the diesel had been removed.
This has been discussed a lot and now it up to the OP to decide what he is going to do.
If you give 5 design engineers a problem they will come up with at least 5 different acceptable solutions.
lw395
Well-Known Member
That's my view too.
A hatch is cost and another thing to go wrong. It's also not very useful if you only have one tank, whereas a boat with three tanks might well be able to empty one to clean it mid season. A boat with serious tankage is also likely to be used differently and might need to clean its tanks more?
For a typical UK boat with one tank, the cost would be better spent on a good filter and the means to extract water/fuel from the bottom of the tank easily. Maybe even a simple polishing set up, or at least have the connections in place.
At least the OP's tank is a good shape, any water will collect at the lower edge.
rogerthebodger
Well-Known Member
Ok Ok i'll stop digging.
Chris_Robb
Well-Known Member
I may have missed something, but there is an absence of a drain tap at the bottom. Considering that the tank is deeper at the forward end, all the water/crap would go to the front. As there is no room for an inspection hatch, put a tap in at the lowest point possible in the tank. I think it would be wrong not to have one.
I understand that UK Red diesel does NOT have FAME (Fatty Acid Methyl Esters- Bio) in it, so you should not worry there BUT if you fill with road diesel which has FAME in it, then I think the tank is best left as empty as possible over winter, as the fuel degrades (3 month shelf life) and a waxy substance falls to the bottom. This is the reason why FAME is not allowed in Marine diesel.
I understand that UK Red diesel does NOT have FAME (Fatty Acid Methyl Esters- Bio) in it, so you should not worry there BUT if you fill with road diesel which has FAME in it, then I think the tank is best left as empty as possible over winter, as the fuel degrades (3 month shelf life) and a waxy substance falls to the bottom. This is the reason why FAME is not allowed in Marine diesel.
sarabande
Well-Known Member
CR - my understanding (from our red diesel farm supplier) is that red does have a Bio component.
Is it just marine red that is FAME free ? I'd hate to put some tractor diesel into the boat's tank, by acccident, of course
The waxy substance, again in my bitter experience, is caused by part of the diesel "recipe" condensing bcs of cold - usually below about freezing. It's like candlewax in the glass fuel filter of the tractors, and can be changed back into liquid, by heating it up with a hairdryer (yes, I keep one in the sheep shed for that very purpose)
I'd be grateful for more details about red and Bio, please.
Is it just marine red that is FAME free ? I'd hate to put some tractor diesel into the boat's tank, by acccident, of course
The waxy substance, again in my bitter experience, is caused by part of the diesel "recipe" condensing bcs of cold - usually below about freezing. It's like candlewax in the glass fuel filter of the tractors, and can be changed back into liquid, by heating it up with a hairdryer (yes, I keep one in the sheep shed for that very purpose)
I'd be grateful for more details about red and Bio, please.
lw395
Well-Known Member
Better to have a standpipe with a connection at the top of the tank, or high up on the side, drawing from the lowest point.
Drains at the bottom are often hard to connect to, a leak risk, prone to damage etc. I've had a bit of fun with an ancient fuel tap weeping diesel.
If all the connections are high up, you can work on them with the tank partly full.
IMHO, the main take off should also draw from pretty close to the bottom. That way the crud and water are mostly going straight to the filter, not lying in the bottom breeding bugs.
My first boat had a tank which needed to be nearly 1/4 full to be sure of drawing diesel not air, there are some curious designs out there!
lw395
Well-Known Member
CR - my understanding (from our red diesel farm supplier) is that red does have a Bio component.
Is it just marine red that is FAME free ? I'd hate to put some tractor diesel into the boat's tank, by acccident, of course
The waxy substance, again in my bitter experience, is caused by part of the diesel "recipe" condensing bcs of cold - usually below about freezing. It's like candlewax in the glass fuel filter of the tractors, and can be changed back into liquid, by heating it up with a hairdryer (yes, I keep one in the sheep shed for that very purpose)
I'd be grateful for more details about red and Bio, please.
AFAIK, there are other bio components than FAME. So FAME-free is not the same as bio-free.
Diesel waxing pre-dates bio.
I think there are several issues, some things just precipitate out when it's too cold, and dissolve again when warmed, others are products of degradation and are permanent.
The permanent degradation of road diesel does not seem too bad if the container is sealed, but IMHO any fuel in any vented tank degrades to some extent these days.
Chris_Robb
Well-Known Member
CR - my understanding (from our red diesel farm supplier) is that red does have a Bio component.
Is it just marine red that is FAME free ? I'd hate to put some tractor diesel into the boat's tank, by acccident, of course
The waxy substance, again in my bitter experience, is caused by part of the diesel "recipe" condensing bcs of cold - usually below about freezing. It's like candlewax in the glass fuel filter of the tractors, and can be changed back into liquid, by heating it up with a hairdryer (yes, I keep one in the sheep shed for that very purpose)
I'd be grateful for more details about red and Bio, please.
Sarabande - I will try to find out - that was certainly the case 4 years ago when all the controversy was going on about our fuel discount with the EU. The case for keeping red diesel was significantly driven by the perceived dangers of FAME breakdown.
The drop out that I have observed in Greece where FAME is about 10%, is a black wax substance - and this of course is present at Med temperatures, and very different from the freezing drop out you refer to. I was recovering fuel pumped out from the tank bottom, that had settled in large water bottles. I accidently poured some of the black wax (it just looked like dirt) into the Racor water separator funnel, and it instantly blocked the cooper filter. It was then that I realised it was not dirt but wax. So just imagine what will happen when there is sufficient accumulation of this muck, to a filter in a rough sea!
I have not heard of anyone else reporting this effect - perhaps we are all in blissful ignorance.........
Mister E
Well-Known Member
I have a Westerly Pageant that has a similar fuel tank set up. If I was replacing the tank I would try to ensure that the tank was reasonably easy to slide forward into the rest of the engine bay.
I think I would even look into moving it forward into the big unused space above the prop shaft. Then I could have a bigger off the shelf tank.
I think I would even look into moving it forward into the big unused space above the prop shaft. Then I could have a bigger off the shelf tank.
