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Water and Rust: How I Thought We Were Sinking


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Hi again, 

 

I'm back with another old boat problem.. 

 

Yesterday we noticed water in the cabin near the front. I checked under the well deck, it was about an inch deep on top of the concrete ballast. Panic set in, could this be canal water? It certainly looked murky. 

 

I hand pumped a few buckets out, and it didn't seem to be getting worse, so we pressed on to our destination where I could do some further investigation. 

 

Then in particular shallow pound, the boat sat on the bank and listed as I filled the lock. I looked under and noticed water coming out of the hole marked below in red. Some also seemed to be coming from the blue area. 

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Behind this bulkhead is my water tank. I've been assuming that it's a separate stainless steel vessel, but could it just be open liquid behind the bulkhead?? 

 

If it is a separate tank, I'm guessing there would be a breather that overflows when I fill the tank up. If that's the case I can't see how I would ever fill my tank without getting water into this area. 

 

Finally, in this photo you can see where the water was pooling. When I wet vac it, it looks like water is oozing from the rusted iron. This is upsetting.. (it's upside down for some reason) 

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1) Does it seem likely my tank is separate stainless steel or just water behind the bulkhead?

 

2) What would the correct action be too fix this issue?

 

3) The rust looks quite bad to me, does it need professional treatment or can I do it myself? 

 

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If this is a riveted boat, then professional repair will be required, by someone who really does know what they are doing.

 

Bod,

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50 minutes ago, Bod said:

If this is a riveted boat, then professional repair will be required, by someone who really does know what they are doing.

 

Bod,

It's an old riveted iron hull. Could you suggest what sort of repair I should look for? Iron hull rust repair?

 

 

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13 minutes ago, spicemouse said:

It's an old riveted iron hull. Could you suggest what sort of repair I should look for? Iron hull rust repair?

 

 

 

Rivetted Iron hulls are not DIY, and not even handled by the majority of boatyards. It is a very old system of boat building little understood these days,

You will need to find an 'Iron-Boat' specialist and get the boat to them. Sooner rather than later.

 

It doesn't take long for a 'weep' to be come a 'dribble' to become a flood.

It may be worth looking to find somewhere you can be lifted out whilst you try and find a specialist.

Whereabouts in the country are you ?

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9 minutes ago, Alan de Enfield said:

 

Rivetted Iron hulls are not DIY, and not even handled by the majority of boatyards. It is a very old system of boat building little understood these days,

You will need to find an 'Iron-Boat' specialist and get the boat to them. Sooner rather than later.

 

It doesn't take long for a 'weep' to be come a 'dribble' to become a flood.

It may be worth looking to find somewhere you can be lifted out whilst you try and find a specialist.

Whereabouts in the country are you ?

Currently just north of Hemel Hempstead. Hull survey didn't pick up anything bad.. 😞

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It looks like you have poured concrete in the bottom of the hull. Often used as a last resort. What does your survey say about the hull? I would not try to remove the concrete whilst in the water. There are plenty of yards that can deal with riveted hulls. Don't panic old boats do leak  sometimes, it could just be a rivet that needs welding. I am surprised the surveyor didn't notice the concrete in the hull. I am assuming it has a steel bottom and not  a wooden one. Other repairs would normally be overplating the damaged section or better still cutting out and rewelding in a new section.

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3 minutes ago, Mike Adams said:

It looks like you have poured concrete in the bottom of the hull. Often used as a last resort. What does your survey say about the hull? I would not try to remove the concrete whilst in the water. 

The survey did note the poured concrete yes. 

 

Survey also recommended a small section of overplating around the area in question, which was carried out as part of the work pre-sale. 

7 minutes ago, Mike Adams said:

There are plenty of yards that can deal with riveted hulls. 

 

There aren't many yards around here, I'm heading for London right now. Other than asking if they know what to do with iron hulls, is there anything I could ask them?

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I would suggest you get a full hull survey.  What started out as a small patch of rust on our historic boat turned out to be a much more serious matter.  I don't wish to be a Job's comforter, but maintaining an iron hull can be very expensive.  Whoever does the work for  you should also check that none of the rivets have blown. 

 

P&S at Watford did some good work on the iron hull of our other boat - very sound and professional.  Good luck.

 

 

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4 minutes ago, koukouvagia said:

P&S at Watford

I'm quite close to them, so I'll give them a ring on Monday. Thanks! 

 

5 minutes ago, koukouvagia said:

I would suggest you get a full hull survey

My full pre-purchase survey did suggest the section of overplating that was carried out. The rest of the hull was reported as good. 

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9 minutes ago, spicemouse said:

I'm quite close to them, so I'll give them a ring on Monday. Thanks! 

 

My full pre-purchase survey did suggest the section of overplating that was carried out. The rest of the hull was reported as good. 

I'd had a full hull survey done on the boat pictured above.  No significant problems were identifed. Huh!

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I fear that you do have a problem. You also have a 'Historic' boat. I would rather have an historic boat with corrosion than a modern boat as when repairs are done you will still have a more interesting boat than a very ordinary boat. That said I think it is likely that the lower 12 -18" of the sides will need to be replaced and the bottom could well be an issue as well. Joining iron to steel is OK, Its not something I could do with my ancient Clarkes welder but a proper welder could do it. I think they use stainless welding rods but I am very happy to be put right on that. Good luck.

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If this area has been covered by an inch of water only yesterday it will take a while to dry out even if the source of the water is removed.
Both concrete and scale hold quite a bit of water that will seep into the open in an alarming manner when the surface is hoovered and it can take a few days to dry with good air flow (fans).
Whilst you do need to take this seriously, I'd also want to look at your original theory - the hole circled in red in the initial picture is quite high up - where was that water coming from? Can you see anything through that circular hole?
With a converted old boat the water tank could be in any form or any material, so learning more about it, with a torch, a phone camera, and some contortions (!) could be useful.
 

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2 minutes ago, twooh10 said:

where was that water coming from? Can you see anything through that circular hole?

No, I tried with my phone yesterday and the angle make it very hard to see anything. Looks like an open space such leads me to think the stainless steel tank is a lie, and I have an integral tank. Than hole being an overflow(?). 

 

4 minutes ago, twooh10 said:

Both concrete and scale hold quite a bit of water that will seep into the open in an alarming manner when the surface is hoovered and it can take a few days to dry with good air flow (fans).

I plan to keep it hovered if it fills and use my stove the try dry or all out a bit. I did wonder if it could just drying out. Fingers crossed eh. 

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Did you have a hull thickness survey? If so how did the surveyor measure the hull thickness with the concrete? Some surveyors are not experienced with iron hulls. You really need to see both sides of the plating if possible. It looks as if the footings have been replaced in steel to me as the frames seem to be cut off. I think you may need to take the boat out of the water, remove the concrete and go around it with a heavy hammer. If you are lucky it might be just a local problem where water accumulates. How much of the hull has concrete in it?

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25 minutes ago, Mike Adams said:

Did you have a hull thickness survey? If so how did the surveyor measure the hull thickness with the concrete?

 

Hammered the iron parts. 

Screenshot_20210711-111634.png.e71a4aa279d1ab397e6fca5407728ee0.png

 

30 minutes ago, Mike Adams said:

How much of the hull has concrete in it?

Seems like all of it to me. 

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Has the area outlined in red been replaced or overplated since the survey? Where is this in relation to the leak?

 

The survey talks about the hull side construction but doesn't describe the bottom.  Nor are any bottom thicknesses given. I assume that on the bow section this is also riveted plates. The presence of concrete may be because this was already leaking, and concrete would seal it as well as acting as ballast.  Which is fine until the concrete and ironwork separate and leakage can creep along the interface (causing corrosion in the process), until the water escapes at the edge of the concrete.

 

 

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3 minutes ago, David Mack said:

Has the area outlined in red been replaced or overplated since the survey? Where is this in relation to the leak?

 

The survey talks about the hull side construction but doesn't describe the bottom.  

 

 

The section was overplating yes. 

 

Bottom is in a separate section. It's newer steel, 5.4 - 6mm thickness. 

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The boat is overlapped butt rivetted and just been on dock, where localised repairs have been carried out.

The heat and interference ( twist in dock may  have distorted the overlap joint leading to the weeping.

it might take up with local rusting if you are lucky.

Ive had a few plates weep post docking that have taken up over time, away from areas of repair, bcause of flex in the dock.

Keep a close eye, put in an auto pump, and try not to go aground.

It could also be a rivet damaged during welding or failing.

If you are sure the bottom is good you could run her into soft mud ( a technique we used with composite boats to encourage the leak to slow down and allow it to take up , but its your risk!

 

 

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OK,  Its a bit hard to tell but it looks as though the bottom is indeed new, it overlaps the sides to make what surveyors like to call a 'sacrificial edge' . It is actually just a sensible way of welding the sides to the bottom. It looks like there has been a strip of newish plate fitted  (Outlined in red)  but it seems to have been rivetted along the bottom so 'newish' is in fact quite old. Overplating is OK for most repairs but personally I would like to cut this piece out, it will not disturb the fit out of the boat (?) and it would be a better repair of this gnarly, lumpy, previous repair. Hard to tell of course and a proper welder with a grinder and stuff could tell you differently but that's what I think is going on.

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11 hours ago, spicemouse said:

 

There aren't many yards around here, I'm heading for London right now. Other than asking if they know what to do with iron hulls, is there anything I could ask them?

 

When you say that have you actually checked?

 

Winkwell dock, Middx & Herts boatyard, by winkwell swing bridge. That's just north of Hemel which is where you said you were.

 

 

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Edited by blackrose
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Whilst it’s certainly possible, I’m not yet convinced that this water is actually coming in from the outside, and that needs to be established before you get too excited about the right now. 
Whatever’s happened during today may have given you a better idea, but if you’re still unsure I would suggest completely emptying your water tank, then doing as much as you can to dry the area out - as mentioned above this the concrete and scale wil retain some water so it will stay damp for a while. 
Once you’ve solved your immediate problem you do have some thinking to do as poured concrete ballast can lead to a world of pain:

 

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26 minutes ago, twooh10 said:

Whilst it’s certainly possible, I’m not yet convinced that this water is actually coming in from the outside, and that needs to be established before you get too excited about the right now. 
Whatever’s happened during today may have given you a better idea, but if you’re still unsure I would suggest completely emptying your water tank, then doing as much as you can to dry the area out - as mentioned above this the concrete and scale wil retain some water so it will stay damp for a while. 
Once you’ve solved your immediate problem you do have some thinking to do as poured concrete ballast can lead to a world of pain:

 

 

 

If you do a google search for "concrete ballast in steel hulls" you get 9,480,000 hits, and looking at the first few they are pretty much all saying NO, don't do it.

 

On boats concrete was primarily used as a cheap form of ballast – however in Europe (for new builds) the use of cement based products in steel boats HAS BEEN BANNED. There is a reason for this.

1. The inside of the hull cannot be maintained against corrosion.

2. The slightest crack allows water ingress. Corrosion occurs with moisture between the steel and the cement.

3. The problem is compounded with cement coverings as whenever the hull is deformed e.g. during haul out or the vessel takes the ground. The deformation of plates creates tension in the cement, which it cannot withstand and it cracks, allowing even more moisture to become trapped between the cement and the hull (more water and oxygen = more corrosion).

Cement is relatively easy to remove compared to concrete, however you have to gain access to it if it is underneath a floor and/or holding tanks and/walls etc. Then it is a major problem.

What should be used is hull plating grease as it protects the steel from corrosion, penetrates any gaps between the ribs and plates and it is flexible.

What also happens with the older boats, the rivets can start to weep, allow more water in, which is tolerable if the moisture can be removed. Condensation is water, causing corrosion.

The problem is you cannot see it and cannot get to it and you do not know what is going on there – it is a silent killer on a hull.

Someone asked if we are talking about ballast or just cement/concrete in the bilge that doesn’t matter. The point is that cement/concrete is on the steel, creating the above problems.

The Technical Expert at a well known insurance company was very helpful in our concerns. We telephoned him to discuss the situation and he said:

  • You should avoid concrete in the bilge, we recommend that loose ballast is used.
  • Without the grease on the inside of the hull, there is always a problem with rusting between the ribs and hull plating.
  • Grease is the best thing to use, it is much better than paint. It should be used on all boats of this type as it seals between the ribs and the plating and it is flexible whereas cement is not and it cracks when the boat is lifted or the boat is on the ground.
  • With older hulls there is the problem with rivets popping out (becoming loose).
Edited by Alan de Enfield
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