Captain Pegg

Are you sure they were railway sleepers? Wrong wood and wrong dimensions for a sleeper. Jarrah or Ekki far more likely if they were intended to be sleepers. Outside possibility they were longitudinal timber rail bearers for a bridge. It does seem that 'sleeper' has become a garden centre term for a big slab of wood. Hardwood's are never treated for use as sleepers. JP

Not just in the olden days. Still two or three trains a day to Round Oak from Llanwern. I recall more than one derailment of those trains in the sidings at Round Oak. I see them regularly and more often feel and hear them from home which is about 100 metres away from where they pass. I would though hazard a guess those coils you saw were from Margam (Port Talbot) possibly heading to Llanwern, although there is a daily early morning train of coils from Margam to Corby. Llanwern is only rolling mills these days although all rail borne steel traffic is still staged there whether or not it unloads or loads any product. I was a guest in the cab of a 2400 tonne Llanwern to Dee Marsh (Shotton) steel train three of four years ago. That was an eye opener although it was unfortunately one of those American GM locomotives. It really struggled. JP

It depends how you define galvanising. In lay terms it might wash since the method by which the zinc protects the steel is still galvanic but in technical terms it is not equivalent to hot dip galvanising. Hot dip galvanising produces a chemical bond between the zinc and the oxidised surface layer on the metal and therefore has very strong adherence between the coating and the parent metal. Hot zinc spraying only produces a mechanical bond so the adherence between coating and parent metal is less strong. It also means the process is subject to similar requirements and risks as apply to two pack epoxy in terms of preparation of the surface. The finished coating is porous so it needs to be sealed, although I have seen one company claim this is advantageous as it allows the steel to "breathe". I wouldn't be using them if I wanted it done. JP

I suspect the answer to the first question is familiarity and certainty based on past experience. They are countries with a strong steelmaking tradition after all. That fact may also be the kind of thing an unknowledgable customer finds comforting. Nothing wrong with that but to suggest that those are the only countries producing steel of the designated quality today would be wrong. For starters one obvious omission would be Austria, a country whose steel producers have been at the forefront of technological advances in steel making since the end of the Second World War and remain so today. In terms of usage by a particular fabricator it could simply be lack of local availability of the required product that precludes use. There is lots of European steel happily doing the job it's designed to do all over the UK. I know of 40+ year vintage French and German steel that does exactly what it's neighbouring UK produced sections do. The same applies to more recent Austrian and Italian steels that have been imported to the UK. I work in the field of policy development and technical standards in relation to usage and assurance of these steels and I know of no circumstance in which steels from across Europe are managed any differently to one another or hold different expectations as to performance as UK steel and it really would matter if any of these steels were inferior. The same cannot be said of any steels of 40+ years vintage which suffer chemical segregation, impurities and gas inclusions on account of steel making processes that have long been superseded or improved. That's not to say modern steel is perfect but it's mechanical capabilities and assurance of performance are massively better than older steels if you require to use them to the limits of their capability. The key issue here being that you never do this on a narrowboat. However this situation has not always been the case with all European countries but things move forward as trade becomes more global. Although I don't have experience of them there are now significant quantities of Eastern European and Russian steel imported to the UK seemingly without major issue. Asia is following and unless something major changes in world trade (and that isn't impossible) we will be reliant on it in the foreseeable future. That's why Asian companies have bought UK and European steel producers. They take our expertise and marry it to their modern facilities and paint by numbers approach to process. For the past decade or so steel has been traded as a global commodity which requires adherence to a common Quality Assurance regime to enable export. The principle being that the product must be of the same basic standard no matter it's source. There is no dispute that Asian steel producers have had to up their game as a result. But if you operate a restrictive buying policy over a period of time at what point do you simply not know the state of the art? JP

Looks like a bog standard old school 12v 2D fluorescent light. Midland Chandlers still list replacement tubes on their website but it might be a caravanning shop or website you need to buy a complete replacement light. Perhaps you have tried and drawn a blank? Someone may be along shortly to say they have converted theirs to LED. JP

Joke or not, in terms of narrowboat building it's accurate. There is a massive difference between what technical standards exist, what is routinely manufactured, what is readily available to purchase and what is actually used. In terms of narrowboats it almost always boils down to one. There is good reason for that. There isn't really much need for this discussion. JP

I think some caution is required with scare stories about imported steel. 30 years ago there were similar stories regarding European steel as you hear today with Asian steel. There is a degree of protection of interests involved. I base my comments on speaking with professionals who are now experts in my industry and have previously worked as consultants in the quality assurance of steelmaking, in research developing new alloys, as shopfloor technicians in steel mills, as welders and as non-destructive testers. All of that is relevant to my daily work and I rely on these folk to do my work, part of which requires me to have a working knowledge of specialist steels in respect of their specification, testing and performance. Something I have been involved with for over 25 years although I consider myself a generalist and not an expert. Note that I didn't say steel is produced to the same quality standard worldwide. I said it is produced to a very consistent standard and to the same QA certification. There is a history of failure due to specific flaws in steel in my industry too and that involves steels of which the vast majority were produced in UK mills. That doesn't mean that UK steel is cheap rubbish though I could probably concoct a scare story to that effect from the collection of failed samples I have at my disposal if I wished. There also tends to be a lot of folklore associated with this sort of history so suspicions remain long after the causes have been eliminated. Just picking up on a couple of points you make, do you realise that practically all (if not all) steel reinforcing bar made in the UK is made from scrap? That's the standard process for producing steel by the electric arc furnace method which is used by Celsa in Cardiff to provide the semi-finished product for their rod mill. Also steel converters in integrated iron and steel works are always charged with scrap prior to addition of the pig iron. The thing with steelmaking is that the whole process is all about refining a 'dirty' product be it molten scrap or pig iron into a tightly specified product. You can't buy steel that doesn't contain scrap but it doesn't make any difference to the finished product. Higher grade steel is used in my world specifically to prevent fatigue cracking. Tensile strength isn't the sole issue in play but the general rule is that a higher strength material will exhibit more brittle failure, i.e. it will fail more suddenly, but that isn't the same thing as being more prone to cracking. Weathering steels (of which Corten is a specific product) generate their corrosion resistance by reaction of the surface with the atmosphere to form a specific protective oxide layer. There is no point using them underwater where they won't develop that layer or if you want to paint the steel. I am interested in your assertion that there is history in shipbuilding and offshore of corrosion being linked to correct composition. I inspect steel of varying vintage and origin on a regular basis and I don't see any observable difference in the way it corrodes other than where specific catalysts are present. Is this a personal or second hand experience of yours? JP

Not all mills would necessarily roll all products. 10mm is a standard plate size. BS EN 10025 is a technical specification for hot rolled products. Mild steel refers to a group of steels of which the basic product is S275 (or Grade 43A in old BS4360 speak). Other mild steel grades are available. JP

I fear you have linked to a paper from the internet that was written by a man who did his research on the internet. Note he is a marine surveyor and not a metallurgist or engineer. Much of what he writes isn't relevant to the subject at hand in any case and on first reading seems a little contradictory in itself. I think a fair bit of his steel making history is misguided. Not that it's particularly relevant since the main problem with these debates regarding narrowboats is that nearly all the properties of steel that matter to the metallurgist or engineer aren't relevant to narrowboats. All you need is something that has high fracture toughness and is relatively easy to fabricate and that is why almost all steel boats are built with ordinary grade S275 (43A) steel. That's basic mild steel of the sort that forms the vast majority of worldwide steel usage irrespective that are many other grades and alloys available. It will be more stressed as a result of the locked in forces caused by rolling and straightening than it ever will be by the exertions of cruising the inland waterways. You simply don't need a higher grade and weathering steels have nothing to do with anything in the context of boats. Steel is produced to very consistent standards to the same quality assurance certification around the world as it is a globally traded commodity. Most of what I see and hear in respect of the supposed superior quality of older steel and horror stories concerning imported steel is completely counter to my own professional knowledge and experience or that of the metallurgists I work with who are experts in their field (and that's industry not academia). The design of the shell and the preparation and welding are far more relevant than the steel itself but if longevity is your principal concern you need to think about the environment you keep your boat in, and how you are going to protect and maintain your hull. JP

What struck me about that piece of work when I cruised that section the day before Matty was the completely random line along which the stakes had been driven. The result is a constantly varying width of channel which randomly wanders around including points that jut out and narrow the channel considerably. The level of the bank protection really should be the same as the piling on the opposite bank and it clearly isn't from the photographs above. It doesn't look like it was properly specified and/or controlled. While I concur the result of this will be that the silt will get washed back into the canal when the levels are higher I am not sure about the argument that it is the cause of the level being low. The stakes are inside the line of the old eroded bank so if the level rises the water will flood over the silt to a point no further than where the line of the bank was before the work. It'll create a right mess but I can't see how water is being lost unless something daft has been done at an isolated location. I can corroborate the issue with the bridge holes. I churned up dirt in every one and had to kick back to free the crap from the prop wash after every one. JP

It may be for some but I equally think there are many deadly serious posts. I just saw the thread as the result of a slow news day on CWDF. I am sure there are folks on here who would take Ambridge to your playing of the Archers out loud. JP

I have to say I am a little bemused by the level of umbrage fomented by what seems to me to be a fairly trivial act. JP

My initial thoughts on the 10mm baseplate were that I believe that it is a requirement for a new build to have such whereas the side plates can be 6mm. That's the bit which seemed illogical other than it being a safety requirement around corrosion protection. In reality steel narrowboats have always had thicker base plates than side plates as the earlier ones were typically 1/4" baseplate and 3/16" side plates which is 6.4mm and 4.8mm respectively. Whether this is a carryover from carrying boats I don't now as there would be some logic in having a thicker baseplate in a working boat albeit overall weight was probably at a premium. I am not convinced that headroom would have been a major factor in early steel boats but ease of construction may explain why a thicker baseplate is used if the hull needs to be of a certain weight. The baseplate is one or more large plates welded together that sit on the floor and the boat is built on top of it. It has very little in the way of fabrication requirements in itself. The sides consist of numerous plates which at fore and aft are considerably bent, shaped and welded. Much easier to do that with a thinner plate. The difference in stability of a hull of 10mm base and 6mm sides versus say 8mm for both I doubt is even close to critical for a narrowboat. There must be a reason why no one builds the latter and I suspect it's the above. The point about ballast that gets missed is that the floor sits on the top of the knees (for want of a better word) which are part of the structure of the boat and aren't just there just to provide an air gap between the baseplate and the floor for the ballast to sit in. A thicker baseplate could only ever be economical if it allows the knees to be formed of a smaller section, say 50mm deep channel instead of 76mm, or less of them to be provided. There is naturally space for ballast whether it's filled or not. JP

But that weight doesn't have to be on the bottom of the boat. That same principal could apply to any part of the boat. If it was about weight then the most cost effective solution would be to build a hull of a predetermined weight using the same thickness of steel throughout. If there is an argument for a thicker baseplate on structural grounds it is probably so that the transverse stiffeners can be shallower and hence headroom can be increased. However the same could be achieved by having more stiffeners with the same baseplate thickness. Personally I am sceptical that these things are ever calculated in a scientific way for narrowboats. They are built rather than engineered. JP

The ballast fulfils that function and I suspect has a lot more to do with trim than it does stability given that stability is largely inherent in the design of a narrowboat. Using steel as ballast is an expensive way of doing things. I don't think it's the reason for a thicker baseplate. JP

A bow thruster tube is presumably made of thinner steel than the baseplate and may also be subject to the effects of cavitation which will repeatedly destroy the stable layer of rust and present unstable parent metal to continue an ongoing cycle of corrosion. It may also simply be a trap for dirt. The obvious conclusion from my assertion that environment is the principal cause of corrosion is that you should protect steel from its environment by painting it. It's a better bet than hoping your environment is friendly. The only logical reason I can see that a baseplate is thicker than the side plates on a conventional new build narrowboat is the expectation that it won't be painted. JP

I don't think anyone is assuming it is sound, just working on the basis that in the absence of facts a 19 year old boat with a 10mm baseplate that is currently floating is very unlikely to sink in the next 6 months. It is also probable that is perfectly sound and will remain so for the foreseeable future. I think some hardened boaters see sinking as an occupational hazard. I moor next to a guy who has had two go down and it doesn't worry him. And that's probably a good thing judging by the hull of his current boat. Taking the examples you give what's so reckless about it? Boat in marina sinks overnight, no one dies, no one injured, possibly nobody even aboard. If you live aboard you will probably see the signs before it sinks and haul it out. Dare I suggest it's a worry mostly for folks for whom a boat is their pension fund afloat? A bit of perspective is what Ivan needs from the forum, he's quite capable of doing all the worrying necessary on his own. JP

Ivan, It's nonsensical to worry yourself about things you chose not to establish when you had the chance. You made that decision so you have to live with it, it's doing you no good worrying about it and it's almost certainly unfounded anyway. This business about blasting the complete hull back for ultrasonic testing isn't necessary. No test can cover 100% and it doesn't need to. Rusting simply doesn't work that way. The bottom side should be pretty uniform since it's the same material in the same environment. On the top side of the baseplate there may be enhanced corrosion where water has stood and particularly if that is grey water as that could have some aggressive chemicals in it. If you want more certainty do more testing under the kitchen, bathroom and engine bilges. If you blast the hull you will see the evidence of any pitting and it should be clean and measurable. You won't see rust unless you have been had so I think Neil2 must be lumping rusting and pitting corrosion together. They are not the same process. Are you sure the survey you refer to said there was 1mm of wasting through rusting or that 1mm of pitting was evident all round? The former seems unlikely to me because natural oxidisation of steel under water is very slow unless there are undesirable chemicals in the water. 4 years used to be the normal timescale for blacking and it has become 2 in recent times. I very much doubt it will be a problem to wait until spring but if you do choose to blast it back to bare metal it would be a nonsense not to apply a 2 pack epoxy system. Nice link to railway tracks by the way. You could learn a lot by expanding that thought process. Rails are never replaced due to corrosion by normal environmental processes (i.e. by air and rain) and they are 11mm thick at the edge of the foot. They are however routinely replaced as a result of the impurities and inclusions inherent in older steels. They do suffer pitting on the underside where they are in contact with other materials but not on the exposed surfaces where only rain and air are in play. The steels are specific alloys designed for hardness rather than corrosion resistance. Standard mild steel is used for sleepers in the same environment and is also uncoated. These have a projected lifespan of 75 years. JP

I hope there is a plan for mooring. Could be fun with the trip boats. At least there is bound to be room for a little 'un. Overall though a finish in central Birmingham is a good idea. Hope the BCNS use it for a bit of publicity. JP Have reported my own post to propose the recent posts on this thread are put into a new 'BCNS Challenge 2019' thread.

I suspect you are right about unnecessary overplating. Steel of the same grade corrodes at different rates as a result of environment. A basic understanding of the science of steel composition and corrosion should lead to that conclusion. I could show you lots of evidence of uncoated steel of varying ages, origins and alloys in normal atmospheric conditions that doesn't corrode very much at all. That's because it's all basically iron and subject to the same chemical reactions. I could also also show you what happens when accelerants to corrosion are introduced. Whether a piece of mild steel (which almost all boats are fabricated from) is of good or bad quality in relation to it's specification will almost certainly have no significant bearing on its corrosion resistance properties. I can't see any scientific reason why it should. And all the metallurgists I work with know that modern steel is a far superior product than anything produced 50 years ago. More importantly they also know why. I see the empirical evidence of that on a daily basis. Of course for the reasons stated above that has no bearing on corrosion of narrowboats. JP

Not bad at all is it? I might be persuaded to take mine there one day soon. JP