Overplating on Hull for a fairly new Boat — a red flag?

[Mad Harold]

That area that has been repaired may not be corrosion, but collision damage.

[roland elsdon]

Both sides? Bowthruster tube bodged over?

[GUMPY]

9 hours ago, roland elsdon said:

Both sides? Bowthruster tube bodged over?

That would make total sense as a rusted through tube on a boat that age is a high possibility. 

 

[MtB]

25 minutes ago, Loddon said:

That would make total sense as a rusted through tube on a boat that age is a high possibility. 

 

 

 

I'm inclined to disagree, as a rusted BT tube would only need a patch about 8" in diameter. Must be something else going on to warrant the extra work of cutting, shaping, forming and welding an overplate of that size.

[Murflynn]

On 20/06/2022 at 01:43, Lindapaws said:

I am sorry to totally disagree with you about bad steel.

Since British Steel closed down in England,  boat builders have had to buy new steel plate from Russia and China. But with Russia being at war with Ukraine, another market for steel had to be found in Brazil.

 

They have our UK boat builders over a barrel on cost of steel & every time a new order of steel is ordered it has gone up in price, making overplating more than double in price.

 

For many years the UK has been sending our scrap steel to Russia and now China, not just nbs, but Marine cargo boats too. Our steel has rustical corrosion in it - sent abroad for the steel to be smelted & corrosion removed.

 

However China & Brazil has been re-selling us mild steel with rustical corrosion still contained within the steel & that is the reason why 2 year old nbs are corroding so badly.  We can see rustical corrosion in the new steel plates.

 

You are better buying an older hull with British Steel, that has been well maintained.

 

yeah, everyone should be very cautious about recycled steel that has not had the rustical corrosion removed.  It's very pervasive and could well be spread by not cleaning your hands with alcohol gel.  A bit like Covid-19 really (until it suddenly dawned on Borax and Matt that fresh air is a thousand times more important, that is).  

 

 

 

.........................  coat ........................ 

 

 

Edited June 21, 2022 by Murflynn

[Alan de Enfield]

2 minutes ago, Murflynn said:

 

yeah, everyone should be very cautious about recycled steel that has not had the rustical corrosion removed.  It's very pervasive and could well be spread by not cleaning your hands with alcohol gel.  A bit like Covid-19 really (until it suddenly dawned on Borax and Matt that fresh air is a thousand times more important, that is).  

 

 

 

.........................  coat ........................ 

 

 

 

 

But, fresh air is not a good alternative to steel for a boat hull.

[MtB]

I've never heard this term "rustical corrosion", so I had a Goggle for it. 

 

No results whatsoever. 

 

So I conclude it is not a well known or widespread phenomenon. 

 

 

 

[doratheexplorer]

30 minutes ago, MtB said:

I've never heard this term "rustical corrosion", so I had a Goggle for it. 

 

No results whatsoever. 

 

So I conclude it is not a well known or widespread phenomenon. 

 

 

 

[IanD]

37 minutes ago, MtB said:

I've never heard this term "rustical corrosion", so I had a Goggle for it. 

 

No results whatsoever. 

 

So I conclude it is not a well known or widespread phenomenon. 

 

 

I suspect she means "rusticles", which are what the Titanic was covered in...

 

https://en.wikipedia.org/wiki/Rusticle

[Alan de Enfield]

Give the girl a break - she is a liveaboard boater and has been doing boat moving for 20 years so has a lot of knowledge.

 

She made a simple 'typo' with Rustical instead of Rusticle (not that Rusticle is particularly relevant either)

 

A rusticle is a formation of rust similar to an icicle or stalactite in appearance that occurs deep underwater when wrought iron oxidizes. They may be familiar from underwater photographs of shipwrecks, such as the RMS Titanic and the German battleship Bismarck. They have also been found in the #3 turret, 8-inch gun turret on the stern remains in place of the USS Indianapolis. Rusticles are created by microbial organisms that consume iron.

 

The word rusticle is a portmanteau of the words rust and icicle and was coined by Robert Ballard, who first observed them on the wreck of the Titanic in 1986. Rusticles on the Titanic were the first investigated in 1996 by Roy Cullimore, based at the University of Regina in Canada. A previously unknown species of bacteria living inside the Titanic's rusticles called Halomonas titanicae was discovered in 2010 by Henrietta Mann.

Rusticles can form on any submerged steel object and have been seen on other subsea structures such as mooring chains and subsea equipment. They form more rapidly in warmer climates and can form in water with little to no dissolved oxygen.

 

Edit to add - cross posted with Ian D so it must be correct !

Edited June 21, 2022 by Alan de Enfield

[Captain Pegg]

20 minutes ago, Alan de Enfield said:

Give the girl a break - she is a liveaboard boater and has been doing boat moving for 20 years so has a lot of knowledge.

 

She made a simple 'typo' with Rustical instead of Rusticle (not that Rusticle is particularly relevant either)

 

A rusticle is a formation of rust similar to an icicle or stalactite in appearance that occurs deep underwater when wrought iron oxidizes. They may be familiar from underwater photographs of shipwrecks, such as the RMS Titanic and the German battleship Bismarck. They have also been found in the #3 turret, 8-inch gun turret on the stern remains in place of the USS Indianapolis. Rusticles are created by microbial organisms that consume iron.

 

The word rusticle is a portmanteau of the words rust and icicle and was coined by Robert Ballard, who first observed them on the wreck of the Titanic in 1986. Rusticles on the Titanic were the first investigated in 1996 by Roy Cullimore, based at the University of Regina in Canada. A previously unknown species of bacteria living inside the Titanic's rusticles called Halomonas titanicae was discovered in 2010 by Henrietta Mann.

Rusticles can form on any submerged steel object and have been seen on other subsea structures such as mooring chains and subsea equipment. They form more rapidly in warmer climates and can form in water with little to no dissolved oxygen.

 

Edit to add - cross posted with Ian D so it must be correct !

 

I just took it she meant rust and was embellishing things, perhaps trying to give her post a bit of credibility.

 

What I'd like to see is some evidence behind these statements of 'bad steel' and 'poor quality'. I genuinely don't think the majority of people who use these terms really know what they mean by them. If someone has a sample of a poor steel product post a picture and proof of it's provenance.

 

I did wonder if the poster had some connection to boat building and had some useful knowledge but living on a boat and being a boat mover isn't going to give you that; I'd say you're more likely to hear tales of dubious origin.

 

What you have to remember is that the other end of this same market is building bridges and high-rise buildings with these products. If the global steel market were flooded with dubious imports it isn't the narrowboat community that is going to find it.

 

 

 

[Slow and Steady]

I'm too unknowledgeable to draw conclusions as to the reasons, but all this steel was bare metalled at the same time and the next day...

 

 

IMO you can say that technically, composition-wise, steel should be better these days but that's not my experience. OK the rusty bit is 1.2mm car panel, not 8mm rolled plate but rolled steel is rolled steel? I genuinely have no idea about this other than what I see. The old shelf material was also much more rigid and shrank less with welding despite being the exact same thickness.

Interestingly 50's-60's VW campers were a joy to weld compared to 70's ones for those reasons and the even later after-market panels worse still in terms of rigidity and shrinkage. It's hard to avoid the conclusion that steel is slowly getting worse and worse over the past 50+ years.

Edited June 21, 2022 by Slow and Steady

[Captain Pegg]

3 hours ago, Slow and Steady said:

I'm too unknowledgeable to draw conclusions as to the reasons, but all this steel was bare metalled at the same time and the next day...

 

 

IMO you can say that technically, composition-wise, steel should be better these days but that's not my experience. OK the rusty bit is 1.2mm car panel, not 8mm rolled plate but rolled steel is rolled steel? I genuinely have no idea about this other than what I see. The old shelf material was also much more rigid and shrank less with welding despite being the exact same thickness.

Interestingly 50's-60's VW campers were a joy to weld compared to 70's ones for those reasons and the even later after-market panels worse still in terms of rigidity and shrinkage. It's hard to avoid the conclusion that steel is slowly getting worse and worse over the past 50+ years.

 

Modern steels are tighter grained and harder than older steels. Hardness equates to increased yield strength so it gives a mechanically superior but harder to work product. You are not the first person on this forum to make the observation about the ease of working older steels.

 

The principles of primary iron and steelmaking haven't much changed since the basic oxygen steelmaking process was developed by a Swiss and commercialised by Austrians after WW2 but the sub-processes for elimination of hydrogen, sulphur and other inclusions in the finished product are vastly improved. You couldn't engage a metallurgist in a serious discussion about whether modern steel is better than older steel as an engineering product, it's not a point of discussion within industry. Those older steels will be riddled with hydrogen bubbles and prone to certain volumetric defects (internal cracking) when repeatedly heavily loaded that either can't or don't tend to occur in modern steels. That's because in the world of engineering and technology things never move backwards.

 

As for "rolled steel is rolled steel" that's not strictly true because there are three principle types of steel - carbon, alloy and stainless - and many different grades within each. However ordinary mild carbon steel (S275 or Grade 43A for the old timers) is by far and away the most prevalent and is what pretty much all narrow boats are fabricated with. All carbon or alloy steel will rust since it's surface is chemically unstable so we shouldn't be surprised by your example.  If you left those three samples for (another) 50 years they'd all be fine and probably in a very similar state (which begs the question as to what each looked like before they were cleaned).

 

Propensity to rust is linked to carbon content so it is possible that with subtle changes over the years that modern steels will react more quickly than older steels but I've inspected many tonnes of untreated steel of many different vintages and origins and never noticed this.

 

The notion that any steel rusts to a degree to cause boats to fail structurally in relatively short order - rather than it being an environmental factor - is very highly unlikely.

 

Edited June 21, 2022 by Captain Pegg

[Slow and Steady]

1 hour ago, Captain Pegg said:

Modern steels are tighter grained and harder than older steels. Hardness equates to increased yield strength so it gives a mechanically superior but harder to work product. You are not the first person on this forum to make the observation about the ease of working older steels.

I actually said exactly the opposite, I find that new car panels are soft, bendy and expand/shrink MORE than the old stuff when welded.

[Captain Pegg]

1 minute ago, Slow and Steady said:

I actually said exactly the opposite, I find that new car panels are soft, bendy and expand/shrink MORE than the old stuff when welded.

 Are they thinner?

[Slow and Steady]

10 minutes ago, Captain Pegg said:

 Are they thinner?

 I can only think the makers deliberately buy "soft" steel because it's easier to stamp out the panels? Some suppliers (makers) are much worse than others.

1 hour ago, Captain Pegg said:

If you left those three samples for (another) 50 years they'd all be fine and probably in a very similar state (which begs the question as to what each looked like before they were cleaned).

The 1968 was original VW painted steel, no rust(I cut the rusty bit out).

The old shelving was (smelt like) oil based paint and again no rust.

Both those were cleaned with a poly abrasive disc then degreased with cheap cellulose thinners (gun wash).

The 2010 was transit paint that washed off with same cellulose thinners leaving shiny new metal.

I can't really agree with your 50 year prognosis - a small paint chip in a 1.2mm thk sill I had (new) rusted to a hole in 2 years.

 

Edited June 21, 2022 by Slow and Steady

[Alan de Enfield]

11 minutes ago, Captain Pegg said:

 Are they thinner?

 

Over the years car panels have gone from 1.2mm thick down to 0.8mm thick and in many instances down to 0.6mm.

 

As each reduction was introduced we had to redesign the fastenings used to clip to the panels.

[Captain Pegg]

3 minutes ago, Alan de Enfield said:

 

Over the years car panels have gone from 1.2mm thick down to 0.8mm thick and in many instances down to 0.6mm.

 

As each reduction was introduced we had to redesign the fastenings used to clip to the panels.

 

Quite. The laws of physics say these panels must be thinner, be bigger or be a different material if they bend differently.

[Captain Pegg]

8 minutes ago, Slow and Steady said:

 I can only think the makers deliberately buy "soft" steel because it's easier to stamp out the panels? Some suppliers (makers) are much worse than others.

The 1968 was original VW painted steel, no rust(I cut the rusty bit out).

The old shelving was (smelt like) oil based paint and again no rust.

Both those were cleaned with a poly abrasive disc then degreased with cheap cellulose thinners (gun wash).

The 2010 was transit paint that washed off with same cellulose thinners leaving shiny new metal.

I can't really agree with your 50 year prognosis - a small paint chip in a 1.2mm thk sill I had (new) rusted to a hole in 2 years.

 

 

OK starting at 1.2mm they may struggle but a 10mm thick untreated steel plate just left on the ground in normal outdoor conditions will last decades. It'll rust very quickly initially (actually it'll be covered in mill scale and rust when it leaves the mill) but then very little change year after year after year.

 

Was this sill on a vehicle? That's an aggressive environment with road salts and other chemicals. My point is that if steel if rusting quickly it's because of the environment it is in and not because of the steel. I've seen plenty of untreated carbon and alloy steel sat outside working hard mechanically and lasting many decades.

 

As for 'soft' steel that's not achievable with the same product in the same thickness. Either they are a different thickness or they are a different steel. Are these panels you are talking about on used vehicles?

[Slow and Steady]

18 minutes ago, Captain Pegg said:

As for 'soft' steel that's not achievable with the same product in the same thickness. Either they are a different thickness or they are a different steel. Are these panels you are talking about on used vehicles?

New repair panels for old (70's) vehicles, both being 0.8mm (they are the worst). If one butt welds them together, the new panels expand more than the original steel and rumple up while the original stays flat. One makes allowances of course and frankly I'm glad I gave this up several years ago!

I really do think they must be "different" steel in some way. Maybe even the rolling process makes a difference but as I say I'm no expert.

 

On the sill thing, it took the originals, chipped here and there 40 years to rust through, it was shocking to find a hole after just 2 years. I would admit that VW had a better paint process than I did though, they had a very, very tough, very thin primer layer that seemed as hard as plating though obviously wasn't. Not sure what that was but I guess chips would possibly not get through that.

 

Anyway, the main point was the amusing surface corrosion picture I posted, I only mentioned the shrinking/bendy aspect in case it was somehow related.

 

...and of course I am very fussy when welding old vehicle half panels - fractions of mm's seem massive to me, though funny how the general public seem to think it's easy. 0.1mm height difference butt welding is a step in my eyes and very visible, it's a far more exact science than it's given credit for... much the same as boat welding - we laugh at the agricultural nature of it, but it must be very hard to make a good one.

Edited June 21, 2022 by Slow and Steady

[Captain Pegg]

1 minute ago, Slow and Steady said:

New repair panels for old (70's) vehicles, both being 0.8mm (they are the worst). If one butt welds them together, the new panels expand more than the original steel and rumple up while the original stays flat. One makes allowances of course and frankly I'm glad I gave this up several years ago!

I really do think they must be "different" steel in some way. Maybe even the rolling process makes a difference but as I say I'm no expert.

 

On the sill thing, it took the originals, chipped here and there 40 years to rust through, it was shocking to find a hole after just 2 years. I would admit that VW had a better paint process than I did though, they had a very, very tough, very thin primer layer that seemed as hard as plating though obviously wasn't. Not sure what that was but I guess chips would possibly not get through that.

 

Anyway, the main point was the amusing surface corrosion picture I posted, I only mentioned the shrinking/bendy aspect in case it was somehow related.

 

I think the welding thing may be to do with how thin those replacement panels are, possibly thinner than the originals on the vehicle. Also if the plates on the vehicle have been pressed to shape they will be work hardened to some or other degree which will add stiffness to them that you may not have in the new plate. The specification may also be a bit different. As you say protection is critical in road vehicles and improvements in that field are why the panels can be thinner in modern vehicles.

 

I did post my background earlier but removed it. I worked full time for 32 years as a railway infrastructure engineer and was latterly the lead engineer for Network Rail's track (permanent way) engineering policy and strategy. As NR is one of the country's leading steel buyers and it's demand underpins the existence of an entire steel mill I had to know some stuff but also worked with real experts on a daily basis, folks who had worked in the steel industry as material scientists on the mill floor, in research labs and in global assurance. I still do a bit of consultancy work including advising on prevention of rail failures and that does focus on the particular risks associated with older steels.

 

Probably the most comparable thing to narrowboat baseplates I experienced is that there are about 3 million steel sleepers on the rail network which are cold pressed from an 11mm rolled mild steel plate section. They are untreated and just sit in the stone ballast and are subject to the normal environmental conditions but obviously are subject to heavy loads. They have been standard since 1998 and there are trial products from a decade previous and some much older legacy designs. The projected life is 75 years and not long ago before I left I did some inspections on the earlier installations. 20+ years and they look pretty much like they did when installed i.e. covered in rust but sound with no significant loss of section. A very different story from what we hear in the narrowboat world, and frankly one where getting it right matters so much more.

 

As far as rail steel - a special alloy - is concerned there is no doubt that the best rails available are the ones leaving the mill right now.

 

I was never once engaged in a discussion about the propensity of carbon or alloy steels - old or new - to rusting. It's just not a factor compared to the many other things that the material scientist and engineer is concerned with when working steel to - and occasionally beyond - it's limits.

[Paul C]

Surface rust is a function of surface finish, since the imperfections are nodes where rust formation starts. Have fewer nodes, ie a more polished, smoother surface, and there's less rust anyway. Surface finish is a function of material hardness, if the same process is used to finish it, ie a rolling pass of the same pressure with the same weight and spec of roller, of the same thickness of material.

 

Also, of course, different batches of different steel (ie with different alloying compositions) are likely made in different places so the equipment and details on the process (ie rolling pressure, passes, etc) won't be the same. Even if they're made in the same place there will be variations.

 

It could simply be that a "bad batch" is actually, just a "different" batch which would have been perfectly fine for another application which uses thick sheet steel, but for the rather haphazard and non-ideal processes which go into constructing a narrowboat shell to a cost, its physical differences meant corrosion was able to take hold sooner.

 

Personally I think it might be an old bow thruster tube which was welded over, but there was something else too which meant instead of a small circular patch, a big sheet was put onto the boat. Maybe the repairer had a big sheet and simply CBA cutting it to size. After all it only very approximately fits the boat.

[john.k]

I know from doing refinery tanks that there is often one sheet in a whole tank that has corroded far worse than most of the others..the tanks are never repaired piecemeal,one  leak or thin sheet and its a complete resheet......incidentally ,these sheets corrode on the inside ,the outsides (weather side) are always perfect due to the painting schedule.

[ditchcrawler]

On 20/06/2022 at 06:41, LadyG said:

Sorry, but I've never heard of rustical corrosion,  

You need to watch the latest documentary about the Titanic, Its whats eating the hull over 2 miles below the surface NOAA Ocean Explorer: RMS Titanic Expedition 2003: Rusticles 

[Captain Pegg]

7 minutes ago, ditchcrawler said:

You need to watch the latest documentary about the Titanic, Its whats eating the hull over 2 miles below the surface NOAA Ocean Explorer: RMS Titanic Expedition 2003: Rusticles 

 

It might sink in another century or so.

 

Edited July 6, 2022 by Captain Pegg