NB lifespan?

[SoJo]

I had to chuckle when I read your comment Jason G as I started boating on a Springer more years ago than I care to remember and now have a brand new boat.Sam Springer did a great job of getting lots of people on the water,and I would guess a vast majority of his boats are still afloat.The key to buying a new boat is an established builder(they must be doing something right)and talk to previous customers,they have no axe to grind.There's also alot to be said for a builder who's a boater,they practise what they preach!

[Liam]

Believe it or not there were some narrowboats built of glass fibre too. I saw a 45 - 50 foot one on the Bridgewater Canal a couple of weeks ago, on one of the cruising club's moorings....

 

Aye. which goes by the name of "Venus". It was built by Fibreline and although it says "No. 1" on its side it in fact wasn't the first. An old couple own it and have done since at least 1999, although it was a bit shinier back then! Apparently it's all GRP apart from the rudder, skeg and prop shaft which is stainless steel.

 

I don't know how many Fibreline built but they are no longer trading.

[SoJo]

There's a fibreline boat called Ambition in Alvecote Marina.

[Deltaromeopapa]

I recognise this is a rather old topic but felt I had to add a little. As an engineer interested in buying a NB I have been reading everything I come across. So to be clear I am not a NB specialist. However steel is a generic term for a ferrous alloy which as a minimum contains iron and carbon. Particularly during the 90s and early 2000s there was a lot of imported steel and some of it was of dubious quality having been imported from less well developed nations who were manufacturing from scrap. Having changed job and not being involved in that branch of engineering I cannot comment on what happened after about 2006. The quality of the steel can have quite an impact on its resistance to corrosion. I somehow doubt it is possible to determine what a 20 or 30 year old, or older, boat is made from. But it may explain why some makes corrode more than others.

Further I watched a video about someone blacking their boat with 2 pack which is supposed to last for much longer than bitumen. Having dry docked the boat it was pressure cleaned and the epoxy applied. The boat was resting on several large balls of timber and them floated after blacking presumably to roam the canals for a few years before again receiving further protection. What about the area of hull not accessible due to resting on the timbers? Need I say more. All through this thread the advise has been that it is all about the maintenance. I concur whole heartedly!

[reg]

...... 

Removed irrelevant comment.

Edited December 12, 2021 by reg

[David Mack]

23 minutes ago, Deltaromeopapa said:

The boat was resting on several large balls of timber and them floated after blacking presumably to roam the canals for a few years before again receiving further protection. What about the area of hull not accessible due to resting on the timbers? Need I say more.

We used to always dock Fulbourne at Uxbridge. On the first time we put the boat as far forward in the dock as possible, next time as far back and so on. So at least the bits above the supports got blacked at alternate docking. But that was with bituminous blacking.

More recently, in the above water dock at Aylesbury the supports can be moved to allow full coverage of the bottom (albeit that the last bits to be painted don't really get long enough to harden before re-immersion).

Edited December 12, 2021 by David Mack

[Tracy D'arth]

Many yards now support the hull with clear space underneath even if this involves a relift and prop to get at the bits where the initial supports were.

 

Debdale for instance support on slender props which they move round as they grit blast, zinc spray and epoxy, a lot of work but that is what you are paying for, a proper job.

I have photos of a base plate being treated and they miss not a square millimetre.

 

Wincham Wharf use drums which they reposition the boat on with their container straddle crane.

[dmr]

 

I think most boat yards would agree with you, most boats rust slowly but there are a few that pit quite quickly which is likely to be due to poor steel.

 

The timbers that boats sit on in the drydock are called bostocks, but its currently normal not the black or epoxy the baseplate. "Officially" this is because there is less oxygen down there and rusting is slower. More likely its because it is just too difficult/unpleasant to do in most dry docks.  The boat builders are well on top of this, whist boat sides are in 6mm steel the baseplate is 10mm (or even 12) so it still gets a reasonable life even unprotected.

Edited December 12, 2021 by dmr
accidental quote

[blackrose]

Or don't bother prepping and painting the baseplate. Most people don't whether they're using bitumen blacking or epoxy.

 

Obviously the more paint you can get on the underwater areas of the hull the better, but at a lot of yards getting to the baseplate is impractical. 

[Captain Pegg]

1 hour ago, Deltaromeopapa said:

I recognise this is a rather old topic but felt I had to add a little. As an engineer interested in buying a NB I have been reading everything I come across. So to be clear I am not a NB specialist. However steel is a generic term for a ferrous alloy which as a minimum contains iron and carbon. Particularly during the 90s and early 2000s there was a lot of imported steel and some of it was of dubious quality having been imported from less well developed nations who were manufacturing from scrap. Having changed job and not being involved in that branch of engineering I cannot comment on what happened after about 2006. The quality of the steel can have quite an impact on its resistance to corrosion. I somehow doubt it is possible to determine what a 20 or 30 year old, or older, boat is made from. But it may explain why some makes corrode more than others.

Further I watched a video about someone blacking their boat with 2 pack which is supposed to last for much longer than bitumen. Having dry docked the boat it was pressure cleaned and the epoxy applied. The boat was resting on several large balls of timber and them floated after blacking presumably to roam the canals for a few years before again receiving further protection. What about the area of hull not accessible due to resting on the timbers? Need I say more. All through this thread the advise has been that it is all about the maintenance. I concur whole heartedly!

 

All steelmaking uses scrap.

 

In primary iron and steelworks the steelmaking vessel is charged with a significant volume of scrap in addition to the pig iron from the blast furnace, and in electric arc furnace steelmaking the primary feed is scrap. Both processes make steel that conforms to the same international specifications.

 

I have a 1968 built boat and I have no doubt the 'quality' of the steel produced then is not as consistent as that of today, but I also don't know of any measure of steel 'quality' used in engineering that is likely to have any impact on the performance of a narrowboat, even if the steel didn't actually conform entirely to the specified 'quality' to which it was produced.

 

Although there are many boats that never have the baseplate painted and seem to last decades I won't argue with the advice that it's advisable to paint (mild) steel in any environment if possible (or perhaps I should make that practicable as it's just struck me I've specified the use of unprotected mild steel many times).

Edited December 12, 2021 by Captain Pegg

[john.k]

Any canal boats made of ferro cement?.........dont laugh,this is a viable material for ocean going yachts and trawlers.....seen a great many boats made of no more than chicken wire and spraycrete.

[Tony Brooks]

1 hour ago, john.k said:

Any canal boats made of ferro cement?.........dont laugh,this is a viable material for ocean going yachts and trawlers.....seen a great many boats made of no more than chicken wire and spraycrete.

 

Maidline had some concrete hire cruisers on the Thames and it was not that uncommon to see the yard upriver with a bucket of wet concrete repairing the corner of the transom where it had been swung against a concrete bank. I have seen photos of concrete narrowboat but I think they were just dumb unpowered barges. Because of the narrow locks and amount of stone, concrete and steel edges I am not wholly convinced concrete would be a long lasting material. Too much opportunity for mechanical damage.

[roland elsdon]

I believe the Thames Conservancy had some concrete lighters as well.

I remember the odd concrete narrowboat in the 1980s in the London area.

our boat is 85 years old. She still has some original bottom and lots of sides.

However if she had carried on working as intended when built she would be gone now.

 

you can tell a real boat from a replica, simply by the pitting above the current waterline.

Grit blasting and two pack above the waterline keeps the bits that show ok, below the current waterline it’s a battle against the inevitable.

Personally I think the huge electrical systems both 12v and mains , and lack of movement ( same ph of water) cause corrosion.

[BEngo]

Some concrete narrow horse boats were built around the time of WW1.  There was an article about them in one of the comics, some while back.

I think one ended up on the Thames as a sort of veranda to a home on one of the aits.  There is a picture on the web somewhere.

 

N

[Stroudwater1]

There are seven (?) Ferrocement Barges among the Purton Hulks on the Severn by the G & B canal.

 

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

 

I think these ones are on the Forest of Dean side too? 

 

Edited December 13, 2021 by Stroudwater1
Adding the correct Forest spelling

[ditchcrawler]

3 hours ago, john.k said:

Any canal boats made of ferro cement?.........dont laugh,this is a viable material for ocean going yachts and trawlers.....seen a great many boats made of no more than chicken wire and spraycrete.

2 hours ago, Tony Brooks said:

 

Maidline had some concrete hire cruisers on the Thames and it was not that uncommon to see the yard upriver with a bucket of wet concrete repairing the corner of the transom where it had been swung against a concrete bank. I have seen photos of concrete narrowboat but I think they were just dumb unpowered barges. Because of the narrow locks and amount of stone, concrete and steel edges I am not wholly convinced concrete would be a long lasting material. Too much opportunity for mechanical damage.

Isnt that where the Concoform name came from at Weedon

[Captain Pegg]

Just for background knowledge for @Deltaromeopapa and to explain the context of my response above almost every steel boat ever produced is likely to be BS4360 Grade 43/BS EN 10 025 S275.

 

There is some talk on this forum of at least one stainless steel boat and a wide beam boat fabricated from Corten weathering steel was up for sale not so long ago. It looked terrible as the steel had weathered differently according to where water had drained from the cabin roof. Standard weathering steels are of course formulated to weather in air and not in water.

[john.k]

I wondered about corten ....its been stated on this forum by experts that the metallic impurities in steel cause pitting corrosion......if so ,then 10% or so of copper may /maynot be a good idea.................i might add ,I have a shipping container dated 1972  tagged corten  while having some rust stains on the paint ,is still quite sound .Never been painted by me..

[ditchcrawler]

39 minutes ago, Captain Pegg said:

Just for background knowledge for @Deltaromeopapa and to explain the context of my response above almost every steel boat ever produced is likely to be BS4360 Grade 43/BS EN 10 025 S275.

 

There is some talk on this forum of at least one stainless steel boat and a wide beam boat fabricated from Corten weathering steel was up for sale not so long ago. It looked terrible as the steel had weathered differently according to where water had drained from the cabin roof. Standard weathering steels are of course formulated to weather in air and not in water.

[Tam & Di]

5 hours ago, Tony Brooks said:

 

Maidline had some concrete hire cruisers on the Thames

As did Hi-Line on the Slough cut at Iver. They did suffer rather, as the Slough cut itself is relatively straight, but it then joins the GU mainline at 90º at Cowley Peachey, and most hirers hit the bank ahead of them before they worked out that they needed to move the rudder to go round a bend.

 

Tam

[dmr]

Corten is the ugliest material I have ever seen.  There is a bridge over the Thames in Reading, and also the new canalside Theatre? building in Stone.  Its just horrible.

[Captain Pegg]

17 minutes ago, ditchcrawler said:

 

Bizarre in that the hull is painted, although that's possibly because the steel won't develop the protective weathered layer underwater. I didn't recall that detail. Needs re-blacking mind.

 

 

[nebulae]

Last time I went past,somewhere on the B.C.N I remember two concrete narrow boats holding up the bank

[Captain Pegg]

1 hour ago, john.k said:

I wondered about corten ....its been stated on this forum by experts that the metallic impurities in steel cause pitting corrosion......if so ,then 10% or so of copper may /maynot be a good idea.................i might add ,I have a shipping container dated 1972  tagged corten  while having some rust stains on the paint ,is still quite sound .Never been painted by me..

 

I've never detected there are any true subject matter experts on the forum, I know some professionally against which I can judge I'm not an expert but can and do learn from. I've also never seen anything conclusive in respect of what causes pitting in canal boats.

 

What I do observe - both professionally where I see a lot of untreated steel and on my boat - is that rusting in normal ambient conditions doesn't cause pitting but introduce a catalyst to corrosion - such as abrasion, stray current or chemicals - and it does occur.

 

While I think it's probably true that the precise location of pits in steel is related to the chemical make-up at the surface I don't think it's the result of any specific manufacturing failure. Hence I believe the answer lies in identifying and eliminating the cause, and failing that just keep the thing well protected. Canal boats are already massively over engineered in any case.

 

As for your Corten shipping container, strip the paint off and let the steel do it's work. I can show you plenty of decades old uncoated steel that isn't specifically formulated to be corrosion resistant that's happily working away in serious load bearing conditions.

 

Edited December 13, 2021 by Captain Pegg

[Dav and Pen]

It was never the practice to black the underside of the working boats and we never even thought about it. We did try and keep the inside of the bottom red oxided as thought the rainwater would cause corrosion from the inside. The original bottom plates of the Town class were of 3/8th inch shipbuilding steel and in the case of Tadworth lasted nearly 40 years since then she has had 3 new bottoms so something has changed.

Our Dutch barge was built in 1917 and it was claimed that steel produced before 1920 was of higher quality before all the scrap steel from the First World War was available. The hull was 5.5mm steel and a lot of it was still above 4mm in 2001 but it had some overplating on the bilges and pitting on the waterline having been unused for some years in the brackish waters of Amsterdam harbour.  It is certainly the general practice to black the bottom of all the barges on the continent and they were always high enough when in dock for someone to get underneath. This was one job I was pleased to pay somebody to do.