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Bricks in bow.


Brian_of_Bozeat

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30 minutes ago, PaulJ said:

Not sure how much these were helping with the trim

 

20230306_115648.jpg

 

 

Ah now that reminds me of when we had an African Grey parrot. 

 

We spent ages trying to teach him to shout "HELP HELP - They've turned me into a parrot." 

 

Somehow he didn't seem to to think it was all that funny...

 

 

 

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2 hours ago, MtB said:

For 'money no object' boats, expect pieces of steel. Steel is at least twice the density of bricks and 20 times the price, weight-for-weight! 

I don't know about 'money no object' but steel ballast was the easiest to fit under Fulbourne's floor to reduce the height at the bow and to make boating in the wind with an unloaded fully clothed up boat considerably easier!

https://www.pbase.com/timlewis/ballast_installation

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48 minutes ago, MtB said:

 

 

Ah now that reminds me of when we had an African Grey parrot. 

 

We spent ages trying to teach him to shout "HELP HELP - They've turned me into a parrot." 

 

Somehow he didn't seem to to think it was all that funny...

 

 

 

Funny things African Greys-all the ones I can remember either really loved you or really hated you.

As a Saturday boy I worked in a Bird Farm. One African Grey trained me to hold bits of food in the cage which gave him a good chance to bite my fingers 😀

 

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3 hours ago, MtB said:

And to expand on the point, gold and depleted uranium make better ballast because they are both denser than bricks, steel or lead. 

 

Gold bars can be purchased on line, here: https://www.bullionbypost.co.uk/

 

But I have to admit I've never seen depleted uranium for sale, not even in the really big branches of Wickes. 

 

 

 

Why does it have to be depleted? 

😁

 

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3 hours ago, mrsmelly said:

Soon to be a surplus  from the HS2 white elephant.

 Currently receiving 30 trucks full of concrete a day in the Stockton area, which is why no-one else can source concrete easily.

If they dont use all the trucks, it is just dumped in an ever growing mountain behind the works.

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23 minutes ago, Machpoint005 said:

 

Why does it have to be depleted? 

😁

 

Less radioactive than the normal mix of isotopes, plus you'll want the 235U for your bomb, and/or to convert your boat to nuclear reactor propulsion.

 

Edited by Jen-in-Wellies
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1 hour ago, Owls Den said:

Me nd my old man had a debate about 6 bricks we found in the Bow.


Him thinking it’s ballast, me thinking what are 6 bricks really going to do!

 

Guess he was right ?

It is possible these were Throwing Bricks. Some people with anger issues find throwing bricks is quite therapeutic. 

 

Obviously one must be cautious about the legality of throwing them directly at the target of one's ire but the action of throwing a brick, even if it is at an inanimate object, can help. 

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6 minutes ago, magnetman said:

It is possible these were Throwing Bricks. Some people with anger issues find throwing bricks is quite therapeutic. 

 

Obviously one must be cautious about the legality of throwing them directly at the target of one's ire but the action of throwing a brick, even if it is at an inanimate object, can help. 

A recent commute was on the canal tow path during the cold snap in January, when the cut froze. There is construction work going on and bricks from the previous buildings were scattered and partially embedded in the ice, in an obvious attempt to break through. They were there for several days, before the ice melted and they sank to the bottom.

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Real bricks are worth money. Not checked but London stocks (yellow ones) were a pound each at one time.

 

A lot of boats are ballasted with worthless engineering driveway bricks so not worth digging the floor up. 

18 minutes ago, Brian_of_Bozeat said:

I've been on a boat like that. Didn't float that well...

It wasn't called Kursk was it?

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10 minutes ago, Nightwatch said:

We viewed a boat for sale many moons ago. It had a concrete floor instead of boarding. We didn’t buy it.

Concrete can be good and bad. 

 

Put it in an old boat as a bodge and its bad news but put it in a new boat and it can be brilliant if done right as it seals right up against the steel and stops corrosion. 

 

Of course on a canal boat clattering around in locks it could be problematic. 

 

Concrete is not all it is cracked up to be

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1 hour ago, magnetman said:

Concrete can be good and bad. 

 

Put it in an old boat as a bodge and its bad news but put it in a new boat and it can be brilliant if done right as it seals right up against the steel and stops corrosion. 

 

 

I'm not sure what the difference is? Even on a new boat done right, with the differential thermal expansion & contraction poured concrete ballast can separate from the steel. It only needs a hairline crack and then any water that you do get in the bilges can get between the two creating a rust trap. It might have been done right but who's going to know whether it's separated or not? And even if you find out it has what can you do about it? Having had a boat with poured concrete ballast I'd always avoid it.

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2 hours ago, matty40s said:

 Currently receiving 30 trucks full of concrete a day in the Stockton area, which is why no-one else can source concrete easily.

If they dont use all the trucks, it is just dumped in an ever growing mountain behind the works.

At chipping warden there’s a large batching plant in the compound but the concrete units to make the cut and cover tunnel seem to have stopped being placed. When I drove  a truck mixer any left over concrete was sold to the local farmers who always had a use for it. Not allowed to do that now apparently so tipped in the quarry or some where handy.

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17 minutes ago, blackrose said:

 

I'm not sure what the difference is? Even on a new boat done right, with the differential thermal expansion & contraction poured concrete ballast can separate from the steel. It only needs a hairline crack and then any water that you do get in the bilges can get between the two creating a rust trap. It might have been done right but who's going to know whether it's separated or not? And even if you find out it has what can you do about it? Having had a boat with poured concrete ballast I'd always avoid it.

Out of interest what problems did you get with the boat which had concrete ballast which caused you to dislike the idea? 

Did it sink? 

 

I think the concrete would probably stick to new steel better than old steel unless the latter was incredibly well prepared which is why I assume an old boat ballasted later with concrete would be likely to be worse. 

 

 

I wonder if anyone actually has had any severely negative outcomes from using poured concrete or if the unknown factor kicks in and makes people nervous. 

 

 

Edited by magnetman
typo
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I was informed (by a builder of concrete boats) that the biggest problem is the alkalinity of the concrete attacking the surface layer of the steel and from then corrosion of the steel quickly takes place.

 

This is a very well known problem in the steel reinforced concrete market where the rebar corrodes, the rust expands by about 8 to 10 times the size of the steel causing big cracks in the concrete which then allows contact with atmospheric CO2 which exacerbates the situation.

 

His (and my) worry was that the concrete will 'react' with the steel hull and bring on rapid corrosion.

 

There are a lot of scientific papers on the subject

 

The two main causes of the corrosion of the rebars in concrete are (i) localized failure of the passive film on the steel by the chloride ions and (ii) general failure of the passivity by neutralization of the concrete alkalinity due to the reaction with atmospheric CO2 (carbon dioxide). 

 

Concept-of-electro-chemical-proess-of-steel-corrosion-in-concrete.jpg

 

Fig 1 Concept of electro-chemical process of corrosion of rebars in concrete

At the anode, metallic iron (Fe) is oxidized and electrons are generated. Since the metal is to remain at a state of electron equilibrium, an equal amount of electrons are consumed at the cathode to form hydrogen (H2) gas. The H2 gas tends to remain near the surface of the rebar and the reaction becomes self-inhibiting. The cathode is then said to be polarized and no further reaction is possible unless the protective H2 film is removed (depolarized). H2 can be evolved as a gas, but this process is normally quite slow. More important is the breakdown of the H2 film by the depolarizing action of oxygen (O2). In this case, O2 acts to prevent the buildup of H2 gas by consuming the free electrons. Once the H2 layer is broken, the corrosion reactions are free to continue

Since sodium and chloride ions do not participate in the reaction, the total reaction can be expressed as the sum of anodic and the depolarization reactions. Making use of the reaction H2O = H(+) + OH(-) gives the principal corrosion reaction as Fe + H2O + 0.5 O2 = Fe(OH)2. The compound precipitating is ferrous hydroxide, a form of rust with whitish colour. However, in oxygenated solutions, ferrous hydroxide is further oxidized to ferric hydroxide. The product finally formed is the familiar reddish-brown rust

Type of rebar corrosion

There are two types of corrosion which are observed in the rebars embedded in concrete. These are (i) crevice corrosion, and (ii) pitting corrosion. Crevice corrosion is a localized form of corrosion usually associated with a stagnant solution on the micro-environmental level. Such stagnant micro-environments tend to occur in crevices (shielded area). O2 in the liquid which is deep in the crevice is consumed by reaction with the metal. O2 content of the liquid at the mouth of the crevice which is exposed to air is greater. Hence a local cell is formed in which the anode (area under attack) is the surface in contact with the O2 depleted liquid. In case of pitting corrosion, theories of passivity fall into two general categories. The first one is based on adsorption while the second one is based on presence of a thin oxide film. Pitting corrosion in the first case arises as detrimental or activator species, such as chloride ion, compete with O2 or hydroxyl ion at specific surface sites. By the oxide film theory, detrimental species become incorporated into the passive film, leading to its local dissolution or to development of conductive paths. Once initiated, pits propagate auto-catalytically, resulting in acidification of the active region and corrosion at an accelerated rate.

 

 

This is a typical installation causing Rebar corrosion that I liken to having poured concrete ballast in direct contact with the hull steel. There will be inevitably be micro-cracks in the interface between the concrete and steel allowing access for the O2, Co2 etc.

 

General-mechanism-for-the-corrosion-of-rebars.jpg

Edited by Alan de Enfield
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3 hours ago, blackrose said:

 

I'm not sure what the difference is? Even on a new boat done right, with the differential thermal expansion & contraction poured concrete ballast can separate from the steel. It only needs a hairline crack and then any water that you do get in the bilges can get between the two creating a rust trap. It might have been done right but who's going to know whether it's separated or not? And even if you find out it has what can you do about it? Having had a boat with poured concrete ballast I'd always avoid it.

 

Poured concrete ballast is not accepted on boats on the Continent.

 

Tam

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