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fuel tank help needed

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 630
Forum Description: 630 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=2998
Printed Date: 27 March 2026 at 03:51
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com


Topic: fuel tank help needed
Posted By: panos
Subject: fuel tank help needed
Date Posted: 07 May 2009 at 19:33
Hi,
We have some problems with fuel management:

The 630 has two separate 380 lt fuel tanks and we can separately select where the engine and the generator feed from. Usually we use one to feed the generator and the other the engine to keep track of the consumptions.
Lately we noticed that diesel moves from one fuel tank to the other while sailing, but there is no obvious way this to happen. Any ideas?
Also there is no flexible tube inside the tank, to feed from the deepest point. So if the boat is heeled you run out of diesel with 60 or 70 lt in the tank. Many years ago I used to build model airplanes. We used to connect a flexible silicon tube inside the fuel tank-with a weight attached to the end, and the fuel feeding to the engine succeeded even with the airplane inverted. This flexible tube was called "fisher".Is there any similar device for boats?


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Panos

Hanse 630e - selling her -



Replies:
Posted By: TAIMA
Date Posted: 07 May 2009 at 20:27
Hi Panos,
 
do you actually know the fuel is moving from one tank to the other or do you take this information from what you read on the meters? I have made the experience that those meters are not really accurate and when you level the boat after heeling over  you get very different readings  so I just use them as a reference, but try to keep an eye on what really is in there.
 
We too have noticed shifting, but just confirmed by the meters. My boat has 3 tanks, 2 x 380 L + a 200 l reserve tank which are all 3 beeing filled by the same intake, so I guess we could have some trouble if the tanks and connection hoses are full, in a way that by sifon the fuel actually flows from one side to the other!
 
regards,


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Thomas Pollehne
Hanse 630/06 TAIMA


Posted By: panos
Date Posted: 08 May 2009 at 18:56
Hi Thomas,
Our only way to check what is inside is by the meters. After heeling one tank drops while the other shows more fuel, so I guess fuel is shifting. But of course this might be wrong readings. I will check better. I only read the meters when the boat is flat, but there is a possibility that the meters  float is sticking. This happens when I fill the tanks full! The float sticks to the tank top and doesn't drop, showing always full and suddenly falling to zero, but besides that they work fairly good.


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Panos

Hanse 630e - selling her -


Posted By: HarryNL
Date Posted: 09 May 2009 at 00:05
Hi Panos
 
Have the same experience on my Hanse 531. On this boat there is one fuel intake on SB-deck with about 0.5 meter lower an Y-pice that spits the fuel line to the 2 dieseltanks. When sailing the fuel moves from one to the other tank via this Y-joined. Since your set-up sounds like it is the same as in the 531, I suppose the same thing is happening in your case.
 
Next month I have one of the 4 water tanks rebuild into a fuel tank (need less water with my functioning watermaker:)). I have asked for valves in front of each of the 3 tanks, so I can chose which tank to fill up.
In this way I can prevent that contanimated fuel in one tank can infect the other tanks. In case of a not fully trusted station I will only fill up one tank. Especially water contanimated fuel that cause microbial growth will block fuel filters and stop the engine.
Probably this construction is overdone here in Europe, but planning longer trips to remote places I want to be on the safe site.
 
Regards
Harry


Posted By: panos
Date Posted: 11 May 2009 at 19:12

Hi Harry,

I am suspecting the same but in my 630 we have separate fuel intakes for the two tanks. Since I want to know how much I am spending for the generator and how much for the engine, I will have to separate the two tanks and remove the Y- piece (if there is one). The average consumption of a diesel engine I consider very important since between others shows that it needs servicing (replacing/cleaning the nozzles).



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Panos

Hanse 630e - selling her -


Posted By: ZENYACHT
Date Posted: 30 July 2009 at 00:16
Dear panos

Diesels return the unburned diesel to the tank

That is why the tank switch is twin.

You have to check where is going the RETURN diesel line

Good sailing

ZENCAP

Originally posted by panos panos wrote:

Hi Harry,


I am suspecting the same but in my 630 we have separate fuel intakes for the two tanks. Since I want to know how much I am spending for the generator and how much for the engine, I will have to separate the two tanks and remove the Y- piece (if there is one). The average consumption of a diesel engine I consider very important since between others shows that it needs servicing (replacing/cleaning the nozzles).



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ZENCAP


Posted By: panos
Date Posted: 30 July 2009 at 18:11
Hi,
No we have checked! The diesel returns to the tank it left from. Anyway the engine was not used. The diesel shifts by gravity to the lower tank. We dont know how this is possible since there is no obvious connection between the two tanks.


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Panos

Hanse 630e - selling her -


Posted By: ZENYACHT
Date Posted: 30 July 2009 at 20:54
Dear Panos

Have you though of siphoning at the tank refilling hoses. Both are connected at the fuel intake.

ZENCAP

Originally posted by panos panos wrote:

Hi,No we have checked! The diesel returns to the tank it left from. Anyway the engine was not used. The diesel shifts by gravity to the lower tank. We dont know how this is possible since there is no obvious connection between the two tanks.


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ZENCAP


Posted By: panos
Date Posted: 30 July 2009 at 22:51
Dear ZENCAP,

It is the most probable explanation but since we have two filling points it is very strange to have them connected under the deck. What would be the reason to have two filling points connected together?Ermm


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Panos

Hanse 630e - selling her -


Posted By: ZENYACHT
Date Posted: 31 July 2009 at 01:31
Dear Panos

You are probably right. if you have different port intakes this doesn´.t make any sense. Another Hanse Mystery?

In my case I have two sets of fuel tanks i.e. 2x 225 liters and another 2x 225 liters with a second fuel port intake. So the twin tanks (Port and Starboard) are fefueled with a common hose to the fuel intake.

A pump fills the rear twin tanks from the forward twin tanks.

So I have only one set of twin 2x 225 liters for water,

I don´t have problems of level exchange between fuel ports ( forward and rear) but I have my suspects about the twin tanks fed by the same fuel port as I have seen irregular readings on port and starboard sides

I have to say the Pilliphi meters produce very inconsistent readings.The second day after the delivery we ran out of fuel in Barcelona just half a mile from the marina when the tank reading was 46 liters. We were towed to enter the Marina.

The meter showed 46 liters when it should read ZERO!.

Good luck locating the origin

ZENCAP

















Originally posted by panos panos wrote:

Dear ZENCAP,It is the most probable explanation but since we have two filling points it is very strange to have them connected under the deck. What would be the reason to have two filling points connected together?[IMG]smileys/smiley24.gif" align="absmiddle" alt="Ermm" />


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ZENCAP


Posted By: ZENYACHT
Date Posted: 31 July 2009 at 01:47
Dear Harry

In my 531 I had several engine stops after refueling in Marseille: I think they gave us the bottom of the reservoir or something worst.

To enter the Marina I checked the fuel filter in order to start the engine it was full of black tar.

I replaced the Delphi filter cartridge for my spare and we could restart the engine to get into Port.

In Barcelona we asked why the filter clogged so easily.

They told us that the Delphi filter was a low capacity automotive filter not very forgiving for contaminated fuel.

We have replaced the Delphi filter for a Racor Marine filter. It is four times the size of the Delphi. We never had problems again.

By the way we have placed the Racor filter in the engine room so we can check the filter at sight. the place where the delphi filter was located originally in the 531 under the floor is a nightmare if you have to change this filter at sea..... second time in my life about to get seasickness...I had to get four pills of ginger root to get the job done in one piece.

ZENCAP




Originally posted by HarryNL HarryNL wrote:

Hi Panos
 

Have the same experience on my Hanse 531. On this boat there is one fuel intake on SB-deck with about 0.5 meter lower an Y-pice that spits the fuel line to the 2 dieseltanks. When sailing the fuel moves from one to the other tank via this Y-joined. Since your set-up sounds like it is the same as in the 531, I suppose the same thing is happening in your case.

 

Next month I have one of the 4 water tanks rebuild into a fuel tank (need less water with my functioning watermaker:)). I have asked for valves in front of each of the 3 tanks, so I can chose which tank to fill up.

In this way I can prevent that contanimated fuel in one tank can infect the other tanks. In case of a not fully trusted station I will only fill up one tank. Especially water contanimated fuel that cause microbial growth will block fuel filters and stop the engine.

Probably this construction is overdone here in Europe, but planning longer trips to remote places I want to be on the safe site.

 

Regards

Harry


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ZENCAP


Posted By: keith goodall
Date Posted: 31 July 2009 at 06:11
Hi Panos
 
I think your earlier post as on the money - that is, a problem with the meters. We have exactly the same problem on our 531 that Harry reports. I cannot see any way for the fuel to physically move between the tanks and the Y split filling point is just under the SB deck so I have concluded that it is not syphoning. I think that when on a heel the meters must get a false reading and then hold that reading until the boat as at rest and level. The unusual aspect of this is that the meters do not quickly return to give what I think are the correct readings - they may be correct the following morning. So sticking meters are the problem in my view. As a consequence I never let the tanks drop below around 160 litres so I am not gambling on the meter accuracy.
 
 


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Keith Goodall

Savarna 531#36



www.sailblogs.com/member/savarna



Posted By: panos
Date Posted: 09 August 2009 at 17:56
Hi,

Running out of gas case possibly solved : I suspect that the fuel level gauge is a 4-20mA instrument while the Phillippi instrument is setup as a voltage meter!. I need some instruments to check it, but for sure when the level meter is at the lowest (empty) position the instrument was showing 45 lt.

Also the charger was setup wrongly and the charging stopped when one of the battery banks was full (so that the other never charged). I changed the charger settings and the charger works perfectly. I am disappointed that Hanse doesn't setup the instruments that they install in the boat.


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Panos

Hanse 630e - selling her -


Posted By: Andreas
Date Posted: 18 October 2009 at 13:59
Hello

The problem of the fuel moving  from one tank to the other might be through the breatherhose. If the hoses are interconnected and the boat heels, this could easily happen!
 



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