Fuel tank leak

[Freebee]

You are ruling out syphoning because you think that the returns just enter the top of the tank but what if they don't???????? you cannot be sure unless you have looked inside!! I seem to recall the boat did not come with a generator this was added later so how were the feeds returns connected were there blanks already there waiting maybe they do go down into the fuel?? You need to rule out everything before you go slicing and dicing the tank!

 

[Freebee]

I agree that it looks well built in the pics, but are you saying it's aluminium from them, or because Bouba said so?
I've seen s/steel tanks (non/polished, obviously) whick looked very similar.
Which brings me to the next question to Bouba, what made you say it's aluminium?

look at the pic of the tank top you can tell its alu by the look of the welding on the top and the use of fabricated tube and brackets for the right angle outlet -its aluminium!

 

[Portofino]

Why not just disconnect the pipes attached for a few days .See what happens .

 

[Portofino]

look at the pic of the tank top you can tell its alu by the look of the welding on the top and the use of fabricated tube and brackets for the right angle outlet -its aluminium!

It’s Al as you say the welds are the give away .

 

[Bouba]

I agree that it looks well built in the pics, but are you saying it's aluminium from them, or because Bouba said so?
I've seen s/steel tanks (non/polished, obviously) whick looked very similar.
Which brings me to the next question to Bouba, what made you say it's aluminium?

Well it just looks like it, but it could also be brushed stainless. I did a scratch test today using a screwdriver and it scratch quite easily. Also the welds don’t look stainless more aluminum, but I have nothing definitive

 

[Mistroma]

Stunningly obvious now you've mentioned it.

No need for dye, simply wait to see if the flow stops.

 

[Portofino]

How did you fuel up the geny ?
Your pic shows two fuel lines LHS one cocked red handle presume the Cummins feed and adjacent it’s return ?
ps confirm .

Rhs top is the sender and another electrical sensor ? Fuel temp for Cummins or alarm level or WIF ?

No third geny feeds .

How is that fed and returned ?

 

[Bouba]

You are ruling out syphoning because you think that the returns just enter the top of the tank but what if they don't???????? you cannot be sure unless you have looked inside!! I seem to recall the boat did not come with a generator this was added later so how were the feeds returns connected were there blanks already there waiting maybe they do go down into the fuel?? You need to rule out everything before you go slicing and dicing the tank!

Yes I was only guessing. There was a spare outlet stopcock and the inlet on the tank for the optional genny

 

[Scarron]

I agree that it looks well built in the pics, but are you saying it's aluminium from them, or because Bouba said so?
I've seen s/steel tanks (non/polished, obviously) whick looked very similar.
Which brings me to the next question to Bouba, what made you say it's aluminium?

It’s definitely aluminium, you can tell from the welded on upstands and ports on the top.

 

[Portofino]

Uri Geller been on board and touched the tank . He‘s a dab hand with stainless FWIW .

Hate to think what he could do with AL .

Sorry couldn’t resist .

 

[Bouba]

How did you fuel up the geny ?
Your pic shows two fuel lines LHS one cocked red handle presume the Cummins feed and adjacent it’s return ?
ps confirm .

Rhs top is the sender and another electrical sensor ? Fuel temp for Cummins or alarm level or WIF ?

No third geny feeds .

How is that fed and returned ?

Yes there is another inlet outlet to the port of that picture.
There are wire connectors to each red stopcock handle for the remote fuel shutoff. The sender is to starboard, not sure what that other part is that’s connected to the sender

 

[Mistroma]

How did you fuel up the geny ?
Your pic shows two fuel lines LHS one cocked red handle presume the Cummins feed and adjacent it’s return ?
ps confirm .

Rhs top is the sender and another electrical sensor ? Fuel temp for Cummins or alarm level or WIF ?

No third geny feeds .

How is that fed and returned ?

I had assumed that the generator feed was quite thin and inside the plastic protector. The outlet was similar to the ones for the engine and I discounted a sensor as it wouldn't be in contact with the fuel. Could be another sensor if it extends down into the tank.

Just a matter of disconnecting any pipe and waiting several days as you suggested. A leak from engine or generator will stop after a litre at the most. A tank leak will continue and require removal of a much larger volume.

Of course sod's law says that the fuel level will have just dropped to the level where the tank doesn't leak any more. I'd suggest pouring in another 20 litres of fuel if the leak does stop. That will confirm that the leak stopped because the pipes were disconnected, not because the tank level had dropped.

 

[MapisM]

Folks, I didn't say it's NOT aluminium, just that I wouldn't be so sure.
And neither the weldings nor the fabricated brackets are so clear-cut, imho.
Out of idle curiosity, I checked this website of Bouba's tank builder, and aside from confirming that they build tanks in both alu and s/s, there are some pics which show what I meant when I said that the material ain't so obvious, without touching the thing.
That said, Bouba's scratch test is probably better than any pics, so aluminium it must be, I reckon.

Another question for Bouba, I don't see any bonding wires in the pics, is there one somewhere?
And did you check its good connection with whatever cathodic protection the boat is equipped with?
It's hard to believe that such modern and recent tank can be corroded with no "external" factor/culprit...

 

[Bouba]

Folks, I didn't say it's NOT aluminium, just that I wouldn't be so sure.
And neither the weldings nor the fabricated brackets are so clear-cut, imho.
Out of idle curiosity, I checked this website of Bouba's tank builder, and aside from confirming that they build tanks in both alu and s/s, there are some pics which show what I meant when I said that the material ain't so obvious, without touching the thing.
That said, Bouba's scratch test is probably better than any pics, so aluminium it must be, I reckon.

Another question for Bouba, I don't see any bonding wires in the pics, is there one somewhere?
And did you check its good connection with whatever cathodic protection the boat is equipped with?
It's hard to believe that such modern and recent tank can be corroded with no "external" factor/culprit...

I didn’t check for cathodic protection. I didn’t even think about it. It would be ironic if it is bolted somewhere on the tank and it was the thing leaking ??

 

[MapisM]

Can't speak for your boat specifically, but I've never seen anodes directly bolted on tanks.
So, it's unlikely that you have one hidden somewhere that was never replaced.
A bonding cable or an earth strap is more likely, but potentially also that could detach, corrode, whatever.
But it's also possible that there's nothing...

 

[petem]

Bouba, I wouldn't panic yet. I think it's pretty unlikely a relatively new tank like this would leak. And even if it does, I'm sure the professionals will find a way of extracting the tank or repairing it without demolishing the boat.

Have you asked someone else to take a look at it? A fresh pair of eyes and all that...

 

[MapisM]

Good suggestion from Petem.
I would just add that I'd ask a good/big Beneteau dealer, if possible.
Shouldn't be too hard to find one, in France...

 

[Fr J Hackett]

Good suggestion from Petem.
I would just add that I'd ask a good/big Beneteau dealer, if possible.
Shouldn't be too hard to find one, in France...

I think he's going to one today.

 

[Portofino]

Bouba, I wouldn't panic yet. I think it's pretty unlikely a relatively new tank like this would leak. And even if it does, I'm sure the professionals will find a way of extracting the tank or repairing it without demolishing the boat.

Have you asked someone else to take a look at it? A fresh pair of eyes and all that...

Poor quality AL fabrications and poor installations as the professionals have said have gone in 6 yrs .

Seems they should be mounted on a frame with air circulation around all sides and strapped down as I said to allow hull flexing not to be passed through the tank .
They certainly need anodic protection as AL itself will dissolve say if a S Steel washer, self tapper or what ever touches the AL .
Its part build I am afraid and part the original quality - thickness and weld etc of the construction.

They either last 10 yrs , 20 yrs or outlast the boat if done right and fitted better .It’s a how longs a piece of string answer .

Boubas has no air gaps so damp will fester where there is no drying gap .
I hate liner boats as you know and this includes “grids “ glued down between the inner liner and outer hull .
Because you never know what’s going on between the two layers , the integrity of the grid , the integrity of the adhesive , or in this case what’s soaking up , sitting under the inner skin / liner .

Has the tank pin holes bust out of sight then seeped between the two layers , run back and popped up remote from the hole ??
God knows there’s no air gap to carry out endoscopy !

Oh I have three all on beds , strapped down on frames + air flow and earthed to a remote anode which is in the sea .


This is my long range ( optional fitment extra ) …..note the bolt top rhs that’s connected to the general anodic protection strap that runs the L of the ER . It a welded square with a bolt as opposed to a bolt through the actual tank .Which I think Bouba was worried about ?
Taps / cock is at the bottom as well .Which I did pull the pipe off once to drain off and check for clarity / water / etc etc

The two mains are bigger fitted to the V and identical in construction but with sight glasses ( cocked ) from the bottom so basically I can see what’s at the bottom near as a dam it by opening then up and viewing the bottom of the pipe .Or just drain some off from the bottom plug .

As said first remove the 4 pipes plug them off ,talc up that yellow line I indicated then reassess in a few days .
This will determine./ eliminate
- Machinery from the tank .
- This soaking up between the liner possibility.

Next tank mount it on a frame with flexible straps + suitable air gaps + cocks low down + sight glass(s) + drain plug .

Next boat always start viewings in the ER first ……..after looking at the hull shape
Get a feel for the gen build integrity.

 

[Portofino]

I agree that it looks well built in the pics, but are you saying it's aluminium from them, or because Bouba said so?
I've seen s/steel tanks (non/polished, obviously) whick looked very similar.
Which brings me to the next question to Bouba, what made you say it's aluminium?

Whilst AL can act as an anode and fiz a pin hole if something like a steel washer or self tapper comes in contact SS is not without issues ,
The welds on SS are far higher temp than AL and all sorts of nasty reactions can latently occur down the line .Basically poor welds fail .Poor welds are easy to inadvertently end up with .

SS is stiffer as well so not as flexible as AL so if it’s subjected to the same forces ( an instal issue ) more likely to pop a seam .

Devil is in the details of manufacturer and the installation.

Intuitively sure SS - yes please sir / madam as it’s does not corrode like my kitchen spoons .What can possibly go wrong ?
Buts it the welds and the flexing ( install) that undoes it as tank material in a boat .

AL welds are easier to get right , AL is more flexible , and can be anodic protected .

How ever does not like standing moisture sitting on salty damp surfaces that’s it’s undoing in a boat = air gap mount them .