8mm bottom and poured concrete ballast

[MtB]

Saw an elderly boat for sale a while ago which we quite liked, but we were put off buying it by the thin base-plate (8mm) coupled with poured concrete ballast. Having looked at LOADS of boats since, we are coming to the conclusion that this boat has a lot about it that we like and can't find in other boats.

 

Should we consider buying it after all (at the right price)? Or is a 15 year old hull with a thin base filled with poured concrete simply asking for trouble?

 

All opinions most welcome.

 

Cheers, Mike

[denboy]

heres a story of a friend who`s gas lockers on his cruiser stern were getting a bit rough so he poured a couple of inches of concrete in them to make them nice and presentable and 2 years later there was 2 perfect cuts through the steel at the fill level from the inside

[Keeping Up]

8mm is not thin for a 15 year old boat, that was pretty much the standard around then. Many were still being built as 6mm; and 10mm was usually an optional extra at extra cost so was not often chosen.

 

Can't comment about the poured concrete though

[FORTUNATA]

My boat is over 30 years old and I only just bought it. When it was built I'd have been about 11 years old. Naturally, with regard to the hull, whatever needs fixing will have to be fixed. For that you need a survey and professional advice. Sounds to me like what you could do is try and knock the price down and find out how much a bottom hull replate would come to. Many many old boats have the bottom hull replated but you need a really good boat builder.

My belief is any old boat that's cast by the wayside can be given a new hope of life on the waters if someone is willing to finance the necessary work. How far can you get the sale prive down and how much would it cost to sort out the hull?

 

 

Saw an elderly boat for sale a while ago which we quite liked, but we were put off buying it by the thin base-plate (8mm) coupled with poured concrete ballast. Having looked at LOADS of boats since, we are coming to the conclusion that this boat has a lot about it that we like and can't find in other boats.

 

Should we consider buying it after all (at the right price)? Or is a 15 year old hull with a thin base filled with poured concrete simply asking for trouble?

 

All opinions most welcome.

 

Cheers, Mike

[alan_fincher]

As Allan says, the 8mm bit in itself is fine.

 

Personally I wouldn't touch a boat with poured concrete in it, as there is very little chance of assessing what it might be hiding.

 

I would have thought it highly unlikely it was built that way, so there must be some story behind the decision to lay wet concrete in it.

 

Not what you want to hear, but I'd walk away.

[Timleech]

As others have said, there's nothing intrinsically wrong with an 8mm bottom.

 

You need to find out why the concrete was put in.

IF it was done with proper preparation, and not just poured into rusty steel, it might be fine. Concrete was used as part of the normal construction by some 'old' boatbuilders, as a way of ensuring that 'difficult' areas were sealed. Even some Joshers had concrete in from new

There can be problems if water is allowed to lie on top of the concrete, there can be localised corrosion around the top.

 

On balance, in a buyers' market, there may be too many uncertainties to make it worth bothering with.

 

Tim

[Iain_S]

I would have thought it highly unlikely it was built that way, so there must be some story behind the decision to lay wet concrete in it.

 

Not what you want to hear, but I'd walk away.

 

Some were built this way : Our canal society trip boat has concrete ballast cast into the hull.

 

http://www.ann.street.btinternet.co.uk/b19...bluebellpix.htm

 

No good pictures of the floor, but there is concrete under the junk, honest !

 

Iain

[MtB]

As Allan says, the 8mm bit in itself is fine.

 

Personally I wouldn't touch a boat with poured concrete in it, as there is very little chance of assessing what it might be hiding.

 

I would have thought it highly unlikely it was built that way, so there must be some story behind the decision to lay wet concrete in it.

 

Not what you want to hear, but I'd walk away.

 

 

Hmmmm good point. I hadn't considered that it may not have been built like that.

 

However, there IS thick plastic sheet (like the builder's DPC) under the slabs of poured concrete, laid before the pouring so there is at least a cat in hells chance of removing it should it turn out to be necessary. Everything else about the boat has been done with considerable care and attention to detail (which is one of the attractions about this boat!) so I'm inclined to think it hasn't been done to conceal a disaster.

 

Maybe I'll go and have another look, and see if I can find out how much of the floorspace is loaded with poured concrete. I dunno why but I suspect it may only be in the back of the boat. There are a lot of broken paving stones lying around in the back too, so I wonder if they had trouble getting it low enough in the water with just 8mm base thickness and an engine room 15 ft forward of the stern.

 

I have no burning desire to buy this particular boat, other than it is the ONLY boat we've ever seen that is exactly what we want. Other than the poured concrete!

 

Cheers, Mike

Edited October 15, 2008 by mike bryant

[Malarky]

Get a quote for a new base and sides up to where the concrete ends, and knock that off the price, then you'r covered. Get the cash, explain you don't like the concrete and , make it clear you won't change you'r mind and don't want to haggle, take them to the pub, offer the cash and walk away, with or without the boat!

[John Orentas]

Again, 8mm was and still is good practise, ballasting with wet concrete was not an uncommon method at the time this boat was built, the main contemporary criticism was that the ballast was not adjustable at a later stage, probably not too valid as very few people change the ballast after the build stage.

 

Perhaps surprisingly concrete and bare steel are a good mix, can't remember the detail but both the materials protect one-another chemically, you only have to think about the steelwork within 'steel reinforced concrete'.. Bridges, buildings and other structures have a design life measured in centuries.

 

I have heard people try to make a case that concrete in some way encourages steel corrosion, it is simply not the case and if you are imagining water creating a gap between the two materials that doesn't happen either, they always form an effective bond.

[RobinJ]

Perhaps surprisingly concrete and bare steel are a good mix, can't remember the detail but both the materials protect one-another chemically, you only have to think about the steelwork within 'steel reinforced concrete'.. Bridges, buildings and other structures have a design life measured in centuries.

Its because rust occurs in a slightly acidic environment (presence of CO2), whereas concrete creates a slightly alkali environment (lime)!

Only stops working when rain (or any water) washes the alkali (lime) away - as happens with some old bridges when the tar cracks!

[MtB]

I have heard people try to make a case that concrete in some way encourages steel corrosion, it is simply not the case and if you are imagining water creating a gap between the two materials that doesn't happen either, they always form an effective bond.

Hi John, thanks for your answer.

 

I think corrosion is my primary concern because the concrete and steel in this particular boat are most definitely NOT bonded effectively. They are deliberately separated by a PVC membrane, laid by the builders in each space before pouring the concrete.

 

This, I suspect, creates plenty of scope for corrosion if the bilges ever get wet, as capillary action will draw the water into the whole of the steel/PVC interface where it could remain for extended periods of time supporting corrosion until it has dried out again.

 

Not that the bilges on this boat appeared wet or damp in any way, but if a minor leak occured unnoticed, from a window seal for example (which could easily drain directly into the bilges behind the panelling) I suspect the first the owner might know about it is when the boat sinks. What do you think?

 

Cheers, Mike

[MtB]

Get a quote for a new base and sides up to where the concrete ends, and knock that off the price, then you'r covered. Get the cash, explain you don't like the concrete and , make it clear you won't change you'r mind and don't want to haggle, take them to the pub, offer the cash and walk away, with or without the boat!

1) Good suggestion but it ain't as easy as that! Adding two or three tons of steel in the form of a new base and side plating requires the removal of the same weight of ballast or the boat will sit stupidly low in the water after the work. Not so easy to remove when it's poured concrete...

 

2) Tried that already, sort of. The boat is on brokerage and the broker (understandably) won't let me speak directly to the owner. Broker is unskilled salesman and not interested in explaining to the owner the reasons for our low offer, they just ring the owner and says 'we have an offer of £x, and the owner says NO (also understandably).

 

The boat is clearly overpriced in today's market but the brokers have a vested interest in reassuring the vendor that a higher price can be achieved than mine. The brokers valued it in the first place and now appear to be struggling to retain their credibility, and are very defensive about their valuation.

 

I think I now have to play the long game. Wait and see as it remains unsold and gathering cobwebs. My offer (the only offer) makes the broker's valuation look plain foolish. The most likely outcome the way the market looks now is that the broker gets sacked and the boat vanishes from the market. Far more likely than it getting sold anywhere near it's current asking price!

Edited October 16, 2008 by mike bryant

[bottle]

Steel..................concrete...........................concrete cancer.

 

 

http://en.wikipedia.org/wiki/Concrete_cancer

[stuart]

won't let me speak directly to the owner. Broker is unskilled salesman and not interested in explaining to the owner

 

I can see the reasoning behind it, however why not make it part of your offer? You will only make an offer after talking to the owner.

 

 

If you are concerned over the concrete, get a survey done. If the steel's okay - you could remove the concrete (as its seperate from the hull by the PVC membrane) not an easy job but a good ground breaker will remove that in no time.

 

You'd have to replace it with bricks/slabs afterwards though.

[alan_fincher]

If it's as you describe, effectively using the shell as a mould, but with plastic sheeting between concrete and metal, I'd be fairly concerned.

 

As you have worked out yourself, there is a small but definite water trap there, and over the whole area it covers. If water does get in for any reason, (and as this forum demonstrates both window and plumbing leaks are very commonplace), then it ain't going to dry out.

 

Others may disagree, but it would worry me.

 

If you do pursue it further, you need tio get a clear understanding of why it was put there, and when.

[Malarky]

1) Good suggestion but it ain't as easy as that! Adding two or three tons of steel in the form of a new base and side plating requires the removal of the same weight of ballast or the boat will sit stupidly low in the water after the work. Not so easy to remove when it's poured concrete...

 

2) Tried that already, sort of. The boat is on brokerage and the broker (understandably) won't let me speak directly to the owner. Broker is unskilled salesman and not interested in explaining to the owner the reasons for our low offer, they just ring the owner and says 'we have an offer of £x, and the owner says NO (also understandably).

 

The boat is clearly overpriced in today's market but the brokers have a vested interest in reassuring the vendor that a higher price can be achieved than mine. The brokers valued it in the first place and now appear to be struggling to retain their credibility, and are very defensive about their valuation.

 

I think I now have to play the long game. Wait and see as it remains unsold and gathering cobwebs. My offer (the only offer) makes the broker's valuation look plain foolish. The most likely outcome the way the market looks now is that the broker gets sacked and the boat vanishes from the market. Far more likely than it getting sold anywhere near it's current asking price!

Oh for a simple life!

 

Best find the owner for the sake of the boat.

[Tony Brooks]

As Allan says, the 8mm bit in itself is fine.

 

Personally I wouldn't touch a boat with poured concrete in it, as there is very little chance of assessing what it might be hiding.

 

I would have thought it highly unlikely it was built that way, so there must be some story behind the decision to lay wet concrete in it.

 

Not what you want to hear, but I'd walk away.

 

 

I seem to remember reading that a well known Fens narrowboat builder used poured concrete as standard and some used asphalt directly on top as the flooring. goodness knows where I got it from though so it could be imagination.

[Big Steve]

My 1976 Hancock and Lane has 6mm bottom and poured concrete ballast, no problems (yet!)

[Mick_B]

Just to put a differant slant on this... When some old GCCC barges (60' x 13') were bought for conversion, if the hulls were dubious and not expected to survive being moved concrete was poured in to strengthen them for the trip. This was then removed in dry dock with a Kango and replating carried out.

The concrete reinforced the hull and plugged holes. I have seen a few with a foot of concrete for ballast.

[Guest]

I seem to remember reading that a well known Fens narrowboat builder used poured concrete as standard and some used asphalt directly on top as the flooring. goodness knows where I got it from though so it could be imagination.

I have heard of the ashphalt on concrete too, but have no idea who employed this method.

[alan_fincher]

I have heard of the ashphalt on concrete too, but have no idea who employed this method.

I want to see a video of them reversing the roller up and down the length of the boat........

[John Orentas]

I want to see a video of them reversing the roller up and down the length of the boat........

 

 

An internal asphalt floor is that shinny brown stuff you often seen in council flats and school classrooms.. It is applied very hot and simply smoothed out.. Waterproof and hard wearing, not a bad material for the inside of a boat.

[richardf]

I had an even worse scenario - many years ago I bought a pretty tired old David Piper that had been part of the Twin Ram hire fleet (anyone remember them?). It had concrete ballast and in fact that was the floor of the boat - I can recall having carpet fitted onto it. Worst of all was the fact that polystyrene sheets had been laid on the base plate and then the concrete floated on top of that. I'm sure there was a real corrosion problem - but I latterly found out that it's many trips up the Llangollen had worn each corner away to almost nothing and I ended up having it replated. Why on earth they did it this way was beyond me!