Sheffield to Anderton on Rallentando

[Rob-M]

We didn't get water in the fuel filters until moored near a lock and when the lock was operated and the levels dropped we sat on the bottom and listed quite a bit.  This was enough to bring the water level in the bottom of the tank high enough to reach the fuel take off and as the engine was running because we were about to set off it sucked quite a bit of water through the system given a cloud of white smoke and the engine cut out.  As soon as the levels came back up and the boat leveled out it wasn't an issue.  We then had quite a bit of water drained out of the tank.

[Midnight]

20 minutes ago, Rob-M said:

We didn't get water in the fuel filters until moored near a lock and when the lock was operated and the levels dropped we sat on the bottom and listed quite a bit.  This was enough to bring the water level in the bottom of the tank high enough to reach the fuel take off and as the engine was running because we were about to set off it sucked quite a bit of water through the system given a cloud of white smoke and the engine cut out.  As soon as the levels came back up and the boat leveled out it wasn't an issue.  We then had quite a bit of water drained out of the tank.

That's more or less what happened to me. A friend was steering but came into a plastic wooden landing stage too fast and the boat wedged under the walkway at a steep angle. 

 

Another possibilty is a fuel cap that wasn't fully sealed. There's a lot of water pouring over the gates behind you when desending into Manchester especially on the nine. If it washed onto the stern and over the filler enough could have found a way into the tank. @IanD suggested the rubber seal on the screw cap was intact, but does water settle around the filler, is the fitting siliconed into the top of the tank and the four screws sealed? If there was an issue with the centre rope causing the boat to heel over at some stage it would fit with @Rob-M 's theory.

 

 

 

Edited October 19, 2023 by Midnight

[nicknorman]

1 hour ago, IanD said:

 

It's just occurred to me that we drew a gallon or so out of the bottom of the tank and left it to settle and there was no sign of diesel floating on water -- but could it *all* have been water? It looked like red diesel but we didn't actually run any between two fingers to check...

I guess that is possible. The red dye does to some extent leach out into water although I would have thought it a lot paler than diesel. If your tank is directly under the filler then do check the filler is well sealed to the deck.

[IanD]

1 hour ago, nicknorman said:

I guess that is possible. The red dye does to some extent leach out into water although I would have thought it a lot paler than diesel. If your tank is directly under the filler then do check the filler is well sealed to the deck.

AFAIK it's well sealed  but I'll check again  when I get back to the boat -- on the way to pick the car up from Sheffield now.

 

The generator started playing up when we were cruising along, and there hadn't been anything to tip the boat over sideways previously.

 

It all looked like red diesel. But this was after we'd filled the tank up with 100l of fresh diesel from Moany Karen at Hesford Marine, so maybe this stirred everything up?

Edited October 19, 2023 by IanD

[nicknorman]

10 minutes ago, IanD said:

AFAIK it's well sealed  but I'll check again  when I get back to the boat -- on the way to pick the car up from Sheffield now.

 

The generator started playing up when we were cruising along, and there hadn't been anything to tip the boat over sideways previously.

Of course the other possible point of water ingress is the tank vent, which from the photo is one of those up the middle of the dolly. We don’t have one like that so I’ve no experience of them, however it doesn’t seem unfeasible that water could get in there if there was a torrent cascading onto the deck from a lock etc.

[cuthound]

2 hours ago, Rob-M said:

We didn't get water in the fuel filters until moored near a lock and when the lock was operated and the levels dropped we sat on the bottom and listed quite a bit.  This was enough to bring the water level in the bottom of the tank high enough to reach the fuel take off and as the engine was running because we were about to set off it sucked quite a bit of water through the system given a cloud of white smoke and the engine cut out.  As soon as the levels came back up and the boat leveled out it wasn't an issue.  We then had quite a bit of water drained out of the tank.

 

Those are exactly the symptoms I had when my shareboat was filled with diesel and water from a contaminated bulk tank.

 

The boats filled earlier than mine took diesel from above the water contaminated level. I was unlucky in getting the last of the diesel and the first of the water!

 

When I persuaded the supplying boatyard to check their bulk tank for water contamination, it was found to contain 25% water because they had never drained the bottom of the tank.

[Ken X]

This is assuming Hesford Marine actually gave you 100% diesel.  Wouldn't be the first time a supplier  has uplifted contaminated fuel.

 

I see Cuthound has beaten me to it.  Must learn to type faster.

[IanD]

10 minutes ago, nicknorman said:

Of course the other possible point of water ingress is the tank vent, which from the photo is one of those up the middle of the dolly. We don’t have one like that so I’ve no experience of them, however it doesn’t seem unfeasible that water could get in there if there was a torrent cascading onto the deck from a lock etc.

We had a couple of locks like that, but it seems unlikely that enough water could get in this way, it looks quite well designed to prevent this (shape, height above deck).

[beerbeerbeerbeerbeer]

Good job this didn’t happen on the Trent,

might have had to deploy the anchor 

[David Mack]

On 18/10/2023 at 11:15, nicknorman said:

 

Of course the other point is that a totally empty tank doesn't suffer from a build up of condensation. As the temperature and relative humidity vary, some condensation may form on the tank insides. But then later when conditions change, it will evaporate again. There can be no nett gain of liquid water.

You only get a build up if the condensation runs down the side of the tank or drips from the roof, and then falls below the level of diesel so that a layer of diesel on top of it prevents evaporation, and then a change of air brings in new moisture.

Not sure I agree with that. Certainly, with any diesel in the tank, any water is trapped beneath it and can't evaporate. But with a closed tank containing only water, with a sealed filler cap and just an open vent connection for ventilation, evaporation of water will result in a some water vapour in the air inside the tank, but only a small proportion of that will be blown out through the vent as the air inside heats up during the daytime, and as the air cools again in the evening/night, damp air will be drawn in and water condense out. So in the right conditions the net effect could well be an increasing amount of water in the tank, just not increasing as fast as if there were also diesel present.

[Tracy D'arth]

Was it BP diesel?

[nicknorman]

31 minutes ago, David Mack said:

Not sure I agree with that. Certainly, with any diesel in the tank, any water is trapped beneath it and can't evaporate. But with a closed tank containing only water, with a sealed filler cap and just an open vent connection for ventilation, evaporation of water will result in a some water vapour in the air inside the tank, but only a small proportion of that will be blown out through the vent as the air inside heats up during the daytime, and as the air cools again in the evening/night, damp air will be drawn in and water condense out. So in the right conditions the net effect could well be an increasing amount of water in the tank, just not increasing as fast as if there were also diesel present.

You are citing the rate of loss of water from a tank already containing water, and I’d agree that this will be very slow. But this is not the same as a tank that starts off empty. As the ambient temperature and relative humidity fluctuates, condensation will form and evaporate but there is no mechanism to create an increasing reservoir of water in the tank.

[BoatinglifeupNorth]

The puzzling thing here is how quickly the water has got into the water trap filter/Generator, your talking since picking the boat(new build) up a week ish before contamination/generator fail. The fuel tank is a standard Narrowboat fuel tank from what I know, with fuel outlet/tap near the top and pick up pipe a few inches from bottom of the tank. 
 I don’t know if there’s a drain plug near the bottom of the tank, but the only reason I can see for such a short period of running 48hrs before water contamination is that the generator fuel line maybe could of been plumbed into this and not the correct fuel line outlet??

  All a bit puzzling with just 48hrs generator running time.

Edited October 19, 2023 by BoatinglifeupNorth

[cuthound]

1 hour ago, David Mack said:

Not sure I agree with that. Certainly, with any diesel in the tank, any water is trapped beneath it and can't evaporate. But with a closed tank containing only water, with a sealed filler cap and just an open vent connection for ventilation, evaporation of water will result in a some water vapour in the air inside the tank, but only a small proportion of that will be blown out through the vent as the air inside heats up during the daytime, and as the air cools again in the evening/night, damp air will be drawn in and water condense out. So in the right conditions the net effect could well be an increasing amount of water in the tank, just not increasing as fast as if there were also diesel present.

 

^^^^

This. i used to get about 15 litres of condensation over winter in my bow thruster compartment until I realised that leaving the access to it open allowed the condensation allowed the condensation to evaporate rather than collect.

[Paul C]

Could it be the builder filled the diesel tank with water at some stage during the build (to do some welding) then didn't do a terribly good job at draining it and reverting it to using diesel?

[David Mack]

1 hour ago, nicknorman said:

You are citing the rate of loss of water from a tank already containing water, and I’d agree that this will be very slow. But this is not the same as a tank that starts off empty. As the ambient temperature and relative humidity fluctuates, condensation will form and evaporate but there is no mechanism to create an increasing reservoir of water in the tank.

Each time the air in the tank contracts in the late afternoon/evening/night, humid air will be drawn in through the vent. If the night is cold enough, some of that water will then condense out as liquid. For there to be no buildup of water over time as you contend, all of that water will have to evaporate the following day as the tank warms up. If this was an open puddle on the ground that could easily happen, but with most of the now damp air remaining in the tank, very little of that water actually gets out. The next evening/night more damp air is sucked in, and so over 24 hours there has been a small increase in the amount of water in the tank. 

[nicknorman]

41 minutes ago, David Mack said:

Each time the air in the tank contracts in the late afternoon/evening/night, humid air will be drawn in through the vent. If the night is cold enough, some of that water will then condense out as liquid. For there to be no buildup of water over time as you contend, all of that water will have to evaporate the following day as the tank warms up. If this was an open puddle on the ground that could easily happen, but with most of the now damp air remaining in the tank, very little of that water actually gets out. The next evening/night more damp air is sucked in, and so over 24 hours there has been a small increase in the amount of water in the tank. 

By that analysis, given enough time the tank would become full of water. But that doesn’t happen. So I disagree with your analysis but there is no point in arguing about it as it’s just my opinion against your opinion.

[Tacet]

Can we have some numbers?  Hours travelling and hours generator running would be interesting.  As would volume of diesel consumed

 

[Paul C]

1 minute ago, nicknorman said:

By that analysis, given enough time the tank would become full of water. But that doesn’t happen. So I disagree with your analysis but there is no point in arguing about it as it’s just my opinion against your opinion.

 

Assuming no water evaporates out of the tank, but it enters, it would still be only a very small amount per day/cycle, thusly: consider the volume of the air above the liquid in the tank (tank capacity - contents); then consider the volume in the air, of the water vapour at daytime temperature and low relative humidity, vs night time temperature and high relative humidity. This difference would be what is condensed each day, and trickles towards the bottom of the tank. Both reducing/eliminating the volume of air above the diesel (eg by keeping the tank as full as possible), and reducing the temperature swing (ie if it were a car, by storing the car in a heated garage) would minimise the issue.

 

The amount of water would build up over time, but it would also be gathered and occasionally drained by the water separator; and/or some water go through the cylinders (water is not completely immiscible in diesel, after all).

 

We're talking small amounts, which is why I don't think the quantity required to stop the generator could have built up in a year or so during the build. Some other "event" needed to occur to introduce water into the tank.

 

tank capacity of 

[nicknorman]

11 minutes ago, Paul C said:

 

Assuming no water evaporates out of the tank, but it enters, it would still be only a very small amount per day/cycle, thusly: consider the volume of the air above the liquid in the tank (tank capacity - contents); then consider the volume in the air, of the water vapour at daytime temperature and low relative humidity, vs night time temperature and high relative humidity. This difference would be what is condensed each day, and trickles towards the bottom of the tank. Both reducing/eliminating the volume of air above the diesel (eg by keeping the tank as full as possible), and reducing the temperature swing (ie if it were a car, by storing the car in a heated garage) would minimise the issue.

 

The amount of water would build up over time, but it would also be gathered and occasionally drained by the water separator; and/or some water go through the cylinders (water is not completely immiscible in diesel, after all).

 

We're talking small amounts, which is why I don't think the quantity required to stop the generator could have built up in a year or so during the build. Some other "event" needed to occur to introduce water into the tank.

 

tank capacity of 

 

The discussion with David was re. a tank with no diesel in it. If there is diesel in it then as I said before, water that runs down the sides and falls below the diesel won't evaporate again.

But as a general point, the mechanism by which condensation occurs is reversible. When the relative humidity is less than 100% liquid water in contact with the air evaporates. Condensation only happens when the air reaches 100% relative humidity. However most of the time, the air is at less than 100% relative humidity and so there will be more tendancy to evaporate than to condense. Only if there is sufficient condensation for surface tension to be broken and droplets to run down under the diesel would the water slowly build up.

It does of course depend on where your diesel tank is located. If above the water line then temperature fluctuations will be significant and the propensity for condensation to occur will be relatively high. If like ours, the tank is entirely below the water line then the propensity will be low. Diurnal variation of air temperature is much greater than that of water temperature, especially a foot or so below the surface.

[Paul C]

Our tank is the back of the stern, so most of it is above the waterline. 

[BoatinglifeupNorth]

2 hours ago, Tacet said:

Can we have some numbers?  Hours travelling and hours generator running would be interesting.  As would volume of diesel consumed

 

Not hard 48hrs, it’s an electric boat, generator has been drawing diesel for 48hrs.

Edited October 19, 2023 by BoatinglifeupNorth

[IanD]

10 hours ago, Ken X said:

This is assuming Hesford Marine actually gave you 100% diesel.  Wouldn't be the first time a supplier  has uplifted contaminated fuel.

 

I see Cuthound has beaten me to it.  Must learn to type faster.

The problem happened before the fillup at Hesford, and went away afterwards...

 

I checked today and the diesel filler is well sealed, and I've been assured that the tank was pressure tested.

 

There has been a small amount of diesel in the tank for a long time during build, then it was filled up before delivery. Maybe the water (condensation?) got in before this?

8 hours ago, beerbeerbeerbeerbeer said:

Good job this didn’t happen on the Trent,

might have had to deploy the anchor 

Which is still sitting in the bow locker, not having been needed on the trip... 😉

Edited October 19, 2023 by IanD

[BoatinglifeupNorth]

15 minutes ago, IanD said:

The problem happened before the fillup at Hesford, and went away afterwards...

 

I checked today and the diesel filler is well sealed, and I've been assured that the tank was pressure tested.

 

There has been a small amount of diesel in the tank for a long time during build, then it was filled up before delivery. Maybe the water (condensation?) got in before this?

Which is still sitting in the bow locker, not having been needed on the trip... 😉

Bow locker??, Thought it was a totally enclosed  “Potters Cabin” front end, or Front/Bow Cabin as the builder says? 

Edited October 19, 2023 by BoatinglifeupNorth

[IanD]

7 minutes ago, BoatinglifeupNorth said:

Bow locker??, Thought it was a totally enclosed  “Potters Cabin” front end, or Front Cabin as the builder says? 

In front of the cabin is a locker with the bow thruster and ballast (and bilge pump!) at the bottom, with a false floor above it to give storage space for hose, anchor, rubbish etc. The hatch over it is a very good fit, even under a veritable waterfall we only got a few drops inside.

Edited October 19, 2023 by IanD