fuel in the bilge

[Dino]

Bavaria 38 Cruiser 2004 end.
I have founf liters of fuel in the bilge, but I'm not able to trace the leakage source. I'm in search of a bilge structure sketch, to properly trace the leak.
It seams the leack is active when the engine is running, but the fuel filters, relevant pipes and exposed portion of fuel tank do not show any leack. Whail sailing the fuel arrive in the bilge but could not understand if the fuel is captured in bilge pockets or....
Thanks

[Dino]

Just few more info, the fuel arrive in the bilge area where the bilge pumps are located, and where the keel bolts are visible.
There is no fuel in the portion of the bilge located under the stairs, or where the engine salt water pump is located.
The portion of bilge located under the engine is difficolt to reach and check, and could not verify if this portion of bilge is in some way connected the the "central" bilge.
Thanks

[Brian]

I had a similar problem, eventually traced it to a small split in the fuel tank. 

[kavok]

I had a leack in the tube immediately out of the tank. The fuel come in the longitudinal structural frame on the engine side, to other  parts of structural frame and arrives in the bigle pumps bigle. I dismounted florr in adt right cabin and all floor from engine and bigle pump zone. The fuel entered in the structural frame, and was a big job to clean! But before you must find lthe leak.

[Dino]

Yesterday, open all floor and cleaning inside the ribs, not really cleaning, but suction the inside with a pump, up to 7+ liters of diesel. The gasoline close to the bilge pumps where clean, while as I moved to stern ribs, or closer to the engine, the gasoline is not clear, and the last rib suction show a dark grey liquid. Pretty strange.
Today I'm planning to run the engine and re-check any leaks.
But the amount of collected waste drive my mind to better inspect the fuel tank, here have the choice to overfill or simulate the sailing tilt.

[sy_Anniina]

Since there is no fuel in engine compartment bilge, the only logical source would be tank or it's immediate fittings.

If you can confirm the leak happens only when engine is running, I would suggest looking at tank outlet pipe and any valves & connections (especially the electronic fuel valve if you have one).

BR,

Tommi
s/y Anniina

[symphony2]

The first place to look is around where the fuel filler pipe goes into the tank. Then inspect all the visible external parts of the tank. Unlikely the leak is from the fuel system to the engine as all the pipes and connections are visible. With that volume of fuel leaking suggests a split in the tank. Once fuel gets in the bilge it slowly works its way down to where the bilge pump is through the limber holes in the grid placed exactly for that purpose. However the grids are hollow so it does not drain straight away but gets trapped. So when you sail and the boat heels the liquid move side to side until some gets through the holes into the next bay. Even when you have found the leak and stopped it there will still be liquid sloshing around until it all works its way down. Not too bad with fresh water which is more common, but horrible with diesel. Therefore priority to get the leak fixed - which may ultimately mean cutting the tank out and replacing it.

[Moodymike]

I had a leak in my B32 which was traced to a badly fitted filler pipe from manufacture, first showed its self when tank was overfilled..

[mowa]

I had the same problem (2005 39Cr) the last year. The problem was the rubber grommets connecting the pipes to the fuel tank. Solved provisionally using Ceys Total Tech. I cannot find the grommet replacement so I made a 3D printer copy but, given the provisional sealing still works, not probed yet.

[Dino]

Thanks to all comments.

@mowa: did you have a picture of the part subject of your comment?

Today 1/2 hour motor running with no leaks detected on all pipes, filters, pumps, etc. and excluding the tha tank and filling pipe.
Drained as mutch as possible the bilge and ribs, very useifull a small electrical pump for oil/diesel from Lidl (purchased the past year).

I would avoid to overfill the tank, next move is to sail for an hour witch should appen this weekend
Ciao

[mowa]

Here is the picture. The leak only happens when heeling. It is difficult to detect because when the boat recover the horizontality the fuel evaporates without leaving any mark on the plastic tank.

Thanks to all comments.

@mowa: did you have a picture of the part subject of your comment?

Today 1/2 hour motor running with no leaks detected on all pipes, filters, pumps, etc. and excluding the tha tank and filling pipe.
Drained as mutch as possible the bilge and ribs, very useifull a small electrical pump for oil/diesel from Lidl (purchased the past year).

I would avoid to overfill the tank, next move is to sail for an hour witch should appen this weekend
Ciao

[Narragansett]

Your post sounds familiar. I had the same problem (2006 33 Cruiser), and have discovered that many Bavaria PE fuel tanks of this vintage are splitting at the seam at an awkward bend near the fuel fill hose, For some reason Bavaria supported these tanks with very little foam and they apparently bend and twist. When the boat heels to starboard the diesel pours out--when you heel to port if runs the length of the fuel tank and then out an opening cut through and into the bilge through a run beneath the engine. Frustrating. Good luck.

[IslandAlchemy]

My tank split many years ago, and I had a new Stainless Steel one made.  Seems a common problem.

[Dino]

The minor leack has been fixed, replaced the horizontal tubing, the lenght of the original was short and forced the side of the rubber bush.


But, after sailing found the main leak, it is close to te filling area, it looks like a joint failure or a installation stress.


This is the manufacturing stamp on tank  by manufacturer.


Is there a repair procedure available somewhere? Material tipe, etc.

[Yngmar]

Tank is HDPE and can be welded (with hot air or another heat source). There was a thread around here somewhere not too long ago about that.

[Dino]

Bavaria GmbH answer do not comment the issue, but offer a new tank as replacement for €560+VAT+Transportation, apart the work needed to remove and replace.

Meanwhile I decided to proceede with hot PE welding.
Purchased an electrical tool, PE sticks and an inox mesh.

A reference picture




Here the steps:
Side view
 

Top view, the other side has a minor deformation and I will not do any work


Electrical welder 80W
 

Detail of plastic welder and PE sticks.
  

Before starting the welding, polyhuretan foam was injected under the tank
 

Welding start


1st step completed


application of inox mesh, preformed to shape the tank surface
 

inox mesh, work in progress. Apply the welder to the mesh, it melt the PE and integrate in it
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Work almost completed, mesh covered with added PE (Light gray)
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Now the test, I have to decide if perform a moderate air pressure test o just fill with fuel.

Thanks to who contributed to this thread, and apologyze for my english

[Bubble32]

What a nightmare! It seems that every time I read this Forum I end up with more things to worry about!

Regarding those rubber grommets which are used at the entry and exit points for the fuel tank - I had a bit of weeping at some of mine and did manage to purchase some more, here: http://www.phoenixmarinesolutions.co.uk/Products/Parker-UCC-Return-Bushes/2802.

They were very easy to replace. The old ones came out easily. I was surprised how thick the plastic of the fuel tank was (I have a 2003 B32) and, until reading these posts, felt confident that the tank was strong. I did notice that the holes were not drilled square through the plastic so I guess this was why there were leaks. I probably did not need to replace the bushes but did so having sourced them, but I put a bit of gasket sealer on them too.