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Poured concrete as ballast

Napton

By Napton
in General Boating

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blackrose Veteran II

blackrose

Posted
Posted (edited)
3 hours ago, Pluto said:

I have seen a concrete wash applied to the inside of the bows on a number of L&LC short boats. It appeared to have been done by Yarwoods, and was, perhaps, a standard anti-corrosion finish at the time.

 

Liverpool Boats used to apply a thick layer of epoxy concrete to integral water tanks - at least they did with my widebeam. After 10 years I finally got down there to have a look. It had protected the steel really well apart from an area at the bottom of the tank (top of the baseplate) where water had got underneath and there was some pitting. 

1 hour ago, Machpoint005 said:

 

The water doesn't evaporate, it becomes chemically combined within the concrete.

 

Concrete doesn't dry, it goes off.

 

I intuitively knew there was something wrong with that water evaporation theory but didn't know why. Seems obvious now you've said it. Thanks for the informative post.

Edited by blackrose
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magnetman Veteran II

magnetman

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Posted

Ballast in canal boats is interesting. Generally speaking it is installed under the floor of the boat.

 

If you get into a situation where you are seriously worried about the status of the inside of the hull are you really going to be taking all the floor up, removing the ballast and inspecting the hull from inside?

 

I mean realistically. OK one might want to do this on an old nackered out narrow boat shell for a full refit but if we're talking about a new boat does it seem likely that poured concrete would actually reduce the lifespan of the hull?
 

It is interesting. I'm not convinced it is good for a canal boat which bashes into things quite a lot but it may well be no worse than loose ballast locked away under a floor.

 

It seems to me the main thing is to avoid condensation running down the sides, use lots of grease on any exposed steelwork and avoid leaks by doing things like having water pumps above the tank rather than below it.

 

The general idea with boats is to avoid letting water get in from above.

 

It is sort of the whole point that the water stays outside. Any water getting into the internal structure of the boat is Bad News regardless of what the ballast is.

 

Also steel is an easily repairable material. I think if the ballast was concrete you could probably get away with cutting out rotten steel from outside and welding on new plates rather than overplating existing material.

 

Maybe a bit of a bodge but I never liked insurance in the first place.

 

 

 

 

 

14 minutes ago, roland elsdon said:

On Taggs island?

 

It was near there. Actually Platts Eyot.

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David Mack Veteran II

David MackDonate to Canal World

Posted
Posted
2 hours ago, Machpoint005 said:

 

The water doesn't evaporate, it becomes chemically combined within the concrete.

 

Concrete doesn't dry, it goes off.

Concrete needs more water than is required purely for the chemical reaction, in order to get a workable mix that can be properly compacted. Thus while some of the water does chemically combine with the cement, some of it needs to dry out by a process of evaporation from the surface and diffusion through the concrete matrix to get to the surface. 

The chemical setting reaction takes time, and can be adversely affected if the concrete dries too quickly (leaving insufficient water for the reaction), which is why concrete should be kept covered for a few days after pouring, particularly in hot, dry or windy conditions. 

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BoatinglifeupNorth Rising Star

BoatinglifeupNorth

Posted
Posted (edited)
4 hours ago, Napton said:

Many thanks for all your comments both for and against concrete and integral tanks. You’ve sort of reinforced the impression I got that this was a load of bull. I guess if I won that boat, I’d sell it and get a decent one. But I haven’t bought a ticket! 🤣

Take your time,  no one has used that type of ballast or tank for many years, maybe they’re trying to make money on the job. Stay clear. 

 

 

Edited by BoatinglifeupNorth
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MtB Veteran II

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Posted
Posted
3 hours ago, howardang said:

There is nothing too problematical about integral tanks as long as they are coated properly and maintained regularly. When i first went to sea and for many years after, most ships had integral fresh water tanks which were cement washed every year. 

 

 

That's one helluva big "as long as".

 

Who here would get inside their integrated narrowboat water tank and cement-wash it every year, if they had one?

 

C'mon, hands up! 

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BEngo Veteran II

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Posted
Posted
4 hours ago, cobaltcodd said:

The above comment refers to concrete boats, the inference being that if not maintained, they are not insurable, presumably because something happens to it? - but how many of us maintain our ballast (I don't)?  Would you have to set up a maintenance regime for it if it was concrete?

 

Generally what happens is mechanical damage which exposes the steelworks. Yachties can from time to time hit things, ranging from semi-submerged containers to passing quays.  If this damage  is  patched up properly then no probs.  If the steel is allowed to go rusty the bond between concrete and steel is weakened.  In bad cases the concrete spalls, aka comes off in chunks.

 

Maintain ballast?  Few do, but once  water either as condensation  or from leakage gets onto the bottom plate then corrosion  is going to happen unless and until the bilge is thoroughly dried.  The tiny gaps between brick or slab ballast and the baseplate are ideal for trapping water and very hard to fully dry. This is  a home from home for corrosion.

 

N

 

 

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howardang Influencer

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Posted
Posted
32 minutes ago, MtB said:

 

 

That's one helluva big "as long as".

 

Who here would get inside their integrated narrowboat water tank and cement-wash it every year, if they had one?

 

C'mon, hands up! 

Quite right. I wasn’t for one second suggesting that for canal boats but rather mentioning it for context and possible mild interest for some people. When I was a cadet I spent many happy hours in fresh water tanks scraping and then cement washing tanks and I’m sure everyone is pleased that there are better ways of doing this essential maintenance which is required by law each year.

 

Howard

 

 

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David Mack Veteran II

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Posted
Posted
28 minutes ago, MtB said:

Do wooden boats ever get graced with poured concrete?

I'm aware of wooden (and composite) narrowboats having poured concrete over soft bits of the bottom planking. Supposedly a bit longer lasting than a lump of clay with a brick on top, but still really only a temporary solution.

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Machpoint005 Veteran II

Machpoint005

Posted
Posted
2 hours ago, David Mack said:

Concrete needs more water than is required purely for the chemical reaction, in order to get a workable mix that can be properly compacted. Thus while some of the water does chemically combine with the cement, some of it needs to dry out by a process of evaporation from the surface and diffusion through the concrete matrix to get to the surface. 

The chemical setting reaction takes time, and can be adversely affected if the concrete dries too quickly (leaving insufficient water for the reaction), which is why concrete should be kept covered for a few days after pouring, particularly in hot, dry or windy conditions. 

 

You do need enough water to hydrate the mixture, but it combines with the chemicals in the cement.

MtB was suggesting that the "evaporation" takes "a year or two", which is incorrect. 

 

This may help:  about concrete

 

 

 

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magnetman Veteran II

magnetman

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As was alluded to earlier if a boat fabricator is offering to install concrete ballast one ought to do due diligence and be there when it is poured. 

 

I don't know how the law works on dismembered bodies but yes it is quite a handy disposal method. 

 

It would be rather rude to be lumbered with someone else's body parts later on when using the kango to alter the ballasting due to installation of something like a more modern lavatory. 

 

Always know what is in your boat. 

 

 

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MtB Veteran II

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Posted
Posted
13 minutes ago, magnetman said:

I don't know how the law works on dismembered bodies but yes it is quite a handy disposal method. 

 

Dunno about you, but I'm inclined to think the law says it's mildly illegal! 

 

 

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magnetman Veteran II

magnetman

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Posted
17 minutes ago, MtB said:

 

Dunno about you, but I'm inclined to think the law says it's mildly illegal! 

 

 

I imagine it is illegal to place the parts in the mix but I was wondering about the status of a boat owner who later finds that their ballast contains missing persons. 

 

It could be quite an interesting transfer of responsibility. 

 

I harbour suspicions that my boat has something dodgy in the concrete ballast as the man who made the boat was a stone mason. 

 

A little bit of extra income perhaps. 

 

We pay good money to get rid of bodies. 

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