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Why Aren't Narrowboats Built With ...


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13 minutes ago, Alan de Enfield said:

 

I think that the 'modern' availability of steel plate is just 2 metres (6'6") which is why NB's are now manufactured to 6'10" max beam (at the gunwale)

 

The boat built with that 7' plate has a beam of 6' 10" but it does have a square hull as do other shells I have seen from the same builder. I expect it may be economics that results in a 6' 10" beam boat being fabricated from a 2m wide base plate if that is indeed what is done. Modern boats tend to have a taper to the hull sides and also the rubbing strakes are welded to the outside meaning the hull sides are comfortably less 6' 10" apart even at the widest point. Obtaining a plate wider than 2m from a stockholder shouldn't be a problem for a steelwork fabricator but given 2m is a standard size kept in stock there would be sense in it's use for baseplates.

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1 hour ago, Captain Pegg said:

 

 

 

Out of interest how long do you think a steel narrowboat will last?

I am sure you are aware that it is a difficult question.

I think if a boat has a durable paint coating from new,and is regularly checked and any remedial action taken the hull should last indefinately.

If on the other hand the boat is only taken out of the water for attention when it changes hands,or is only blacked when the existing rust has taken hold,then anything from 25 to 40 years before it fails an insurance survey.

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1 hour ago, Mad Harold said:

I am sure you are aware that it is a difficult question.

I think if a boat has a durable paint coating from new,and is regularly checked and any remedial action taken the hull should last indefinately.

If on the other hand the boat is only taken out of the water for attention when it changes hands,or is only blacked when the existing rust has taken hold,then anything from 25 to 40 years before it fails an insurance survey.

 

It was indeed a loaded question but that's because the canal boating world seems to worry about steel in a way that the engineering industry doesn't. I don't have any better knowledge than you but the logic of applying basic protection and maintaining it is key. Even then I'd go so far as to say that unless a steel boat suffers from some form of accelerated corrosion that causes pitting it is likely to rust from the inside rather than the outside.

 

Again that can be avoided to a degree by simple maintenance but the design of boats so often precludes this. It is also an area where the design is key because the inside of most boats includes internal void spaces within tubular steel sections that are not fully sealed and are obvious corrosion traps.

 

I have a 53 year old steel boat with 35 year old over-plating. I've recently renewed the insurance for another year on a hull survey dating from 2015. It came out the water last year for an inspection at the yard of a well regarded fabricator and experienced overplateror. I remarked that I wanted both the boat and me to last for another 25 years boating and his response was "no reason why it shouldn't".  

 

I may need to have another hull survey soon and despite the reassurance from the above inspection I can't say I won't be a little apprehensive, not least because the rear swims are still the original 4mm equivalent thickness plate. However recognising there may be a need to spend money on the hull at some point was all part of weighing up the risk in deciding to buy what historically is a very distinctive and high quality boat at a budget price. Six years on and that balance of risk is working in my favour, fingers crossed for the next 24...

 

Edited by Captain Pegg
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1 hour ago, David Mack said:

2m wide plate is the norm for baseplates. Wider sheets are available, but anything over 2.5m would be an oversize load subject to movement restrictions. So its not surprising the fabrication industry (not just boatbuilding) avoids wider where possible.

 

 

That's interesting .

 

I would have thought one could arrange for the item to be loaded in such a way as to circumvent the road transport width problem. 

 

 

 

 

 

 

As for boat hull thickness it does seem intriguing that 4mm is viewed as a minimum acceptable to "pass" a survey. Rather conservative I feel. 

 

How does it work with a boat which was originally constructed using 1/8 plate and now shows some readings just above 2mm? 

 

The boat would probably last for ages but the survey will condemn it. 

 

 

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3 hours ago, magnetman said:

I would have thought one could arrange for the item to be loaded in such a way as to circumvent the road transport width problem. 

Well of course you can. But at a cost. For the average narrow boat builder tapering in the hull sides to fit a 2m wide baseplate is a much cheaper and easier option, and the average buyer is happy with the product. So why incur the extra cost?

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On 31/12/2021 at 15:50, waterworks said:

Stop making the Fuel tanks part of the stern, fit an insulated separate stainless tank with a v bottom and proper drain cock. This will stop rusting, codensation and will be easy to flush out the sediment on a regular basis.

… or at least fit an inspection hatch/ plate so that the inside can be got at. 

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7 minutes ago, Iain_S said:

… or at least fit an inspection hatch/ plate so that the inside can be got at. 

 

Which, strangely enough is an RCD requirement, but then, there are all those manufacturers who are not fitting one and yet signing off their boats as compliant.

 

One wonders if they actually have read any of the requirements.

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17 minutes ago, Alan de Enfield said:

 

Which, strangely enough is an RCD requirement, but then, there are all those manufacturers who are not fitting one and yet signing off their boats as compliant.

 

One wonders if they actually have read any of the requirements.

 

The truth is, as in the gas industry, with no policing a self-declaration that work done complies with the regulations is all that is needed. Not that the work actually complies.

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41 minutes ago, Alan de Enfield said:

 

Which, strangely enough is an RCD requirement, but then, there are all those manufacturers who are not fitting one and yet signing off their boats as compliant.

 

One wonders if they actually have read any of the requirements.

Got in first

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27 minutes ago, waterworks said:

If that is going to be on the stern deck then it will cause more problems than it will solve due to potential rainwater leaks.  

The obvious (to me) place to put such a hatch would be below the stern deck, on the vertical face of the fuel tank. It’s not a requirement that the inspection hatch can be used when the tank is full.

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41 minutes ago, Iain_S said:

The obvious (to me) place to put such a hatch would be below the stern deck, on the vertical face of the fuel tank. It’s not a requirement that the inspection hatch can be used when the tank is full.

 

 

Fuel system and fuel tanks

 

ER 5.2.1 The filling, storage, venting and fuel supply arrangements and installations shall be designed and installed so as to minimise the risk of fire and explosion.

 

ER 5.2.2 Fuel tanks -

Fuel tanks, lines and hoses shall be secured and separated or protected from any source of significant heat. The material the tanks are made of and their method of construction shall be according to their capacity and the type of fuel. All tank spaces shall be ventilated. Petrol shall be kept in tanks which do not form part of the hull and are:

(a) insulated from the engine compartment and from all other source of ignition;

(b) separated from living quarters. Diesel fuel may be kept in tanks that are integral with the hull.

 

Harmonised standard: BS EN ISO 10088:2013 Small craft - Permanently installed fuel systems BS EN ISO 21487:2012 Small craft - Permanently installed petrol and diesel fuel tanks

 

The requirements for installation of a fuel system on a boat with fixed fuel tanks are given in the harmonised standard BS EN ISO 10088 Permanently installed fuel systems and BS EN ISO 21487:2012 Small craft - Permanently installed petrol and diesel fuel tanks.

The requirement for petrol fuel tanks to be ‘insulated from the engine and all other sources of ignition’ is deemed to be complied with if

a) the clearance between the petrol tank and the engine is greater than 100 mm and

b) all electrical parts on the engine which could create a spark, and any other electrical components in the engine/fuel compartment, are ignition protected. To ensure that these components are ignition protected the boat builder should use a petrol engine that complies with BS EN ISO 15584 Inboard petrol engines - fuel and electrical system components (the engine manufacture should provide this confirmation) and for other parts, e.g. blower fan or electric bilge pump, use only components that have been CE marked in accordance with Annex II 1. The clearance between a petrol tank and any dry exhaust components must be greater than 250 mm, unless an equivalent thermal barrier is provided. For diesel engine installations, the engines used should comply with BS EN ISO 16147

Inboard diesel engines – Engine-mounted fuel and electrical components to ensure that the fuel components fitted on the engine by the engine manufacturer are safe. The engine manufacture should provide confirmation that the engine complies with this standard.

Fuel hose used in the system must be fire resistant if used in the engine compartment and Where fuel hose is used the standard requires that only fire-resistant hose to BS EN ISO 7840 may be used in the engine compartment. Such hose should be stamped to indicate compliance

 

The following is a requirement in  BS EN ISO 21487:2012

 

If there is a drain in a diesel oil tank, it shall be fitted with a shut-off valve having a plug that can be removed only with tools. Each tank shall have an inspection hatch with at least 150 mm diameter. The inspection hatch shall, as a rule, be located on top of the tank, but for diesel oil tanks it may also be on the tank side. There shall be access to the inspection hatch when the tank is in position.

 

Edited by Alan de Enfield
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How long will a steel narrowboat last?  A very, very long time indeed, Everything above the waterline will last many years with no special attention. Just normal maintanance is OK (A lot of boats actually get hopeless maintainance though) Whatever is below the waterline can be endlessly repaired, overplated, replated and so on. There are many, many ancient iron and steel boats in, for instance Holland that were built with far thinner steel and are still looking very good - as to how many bottoms they have received I do not know.  Interestingly there are many rivetted boats still working commercially, that must date  them to pre 1960's I guess. Again, what lies beneath the waterline is anybody's guess. It is all down to looking after the boat and making a serious effort to look after narrowboats is a very recent phenomonem. The usual way until quite recently was to launch it and slap a coat of black goo on it every 10 years or so.

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3 hours ago, Iain_S said:

The obvious (to me) place to put such a hatch would be below the stern deck, on the vertical face of the fuel tank. It’s not a requirement that the inspection hatch can be used when the tank is full.

That's going to virtually guarantee a fuel leak at some point if you're relying on a seal. 

 

A stainless fit and forget tank would not increase the cost of the shell more than a couple of hundred quid. 

Edited by waterworks
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2 hours ago, Alan de Enfield said:

Each tank shall have an inspection hatch with at least 150 mm diameter. The inspection hatch shall, as a rule, be located on top of the tank, but for diesel oil tanks it may also be on the tank side. There shall be access to the inspection hatch when the tank is in position.

 

The tanks fitted to the GU boats are located under the engine room floor but have a raised triangular section a good 2 ft high at the front end. They are fitted with a bolted inspection hatch in the top of the main underfloor section. So this is in one sense the top of the tank and in another is not. Good job they aren't required to comply with the standard.

7 minutes ago, waterworks said:

That's going to virtually guarantee a fuel leak at some point if you're relying on a seal. 

Same with the GU tanks whenever the vertical extensions are full.

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8 minutes ago, waterworks said:

That's going to virtually guarantee a fuel leak at some point if you're relying on a seal. 

 

A stainless fit and forget tank would not increase the cost of the shell more than a couple of hundred quid. 

 

Lol, where do you buy your stainless steel tanks for £200???!!!

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17 hours ago, waterworks said:

That's going to virtually guarantee a fuel leak at some point if you're relying on a seal. 

 

A stainless fit and forget tank would not increase the cost of the shell more than a couple of hundred quid. 

Not if engineered correctly, we never had a problem when I worked offshore and they were big enough to climb in 

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9 hours ago, ditchcrawler said:

Not if engineered correctly, we never had a problem when I worked offshore and they were big enough to climb in 

They won't be built to offshore level though, most narrow boats are not built to any discenable level than a skip.

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6 minutes ago, waterworks said:

A future big step up in technology will be when vacuum insulation panels become economical, then we can have multiple times the (r value) insulation levels with just 25/30 mm thicknessss. 

 

Currently it stands at around £80 sq/m.

How far off do you think that is? I ask because these thin panels may be useful in residential property which will have to comply with higher energy performance levels soon.

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58 minutes ago, waterworks said:

A future big step up in technology will be when vacuum insulation panels become economical, then we can have multiple times the (r value) insulation levels with just 25/30 mm thicknessss. 

 

Currently it stands at around £80 sq/m.

Can vacuum insulation panels be fitted to the irregular shapes and curved surfaces commonly found on boats? Can they be trimmed to fit on site?

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22 hours ago, David Mack said:

Can vacuum insulation panels be fitted to the irregular shapes and curved surfaces commonly found on boats? Can they be trimmed to fit on site?

No and maybe. The spacing of the framing would have to match the panels as they can't be cut and they can be curved in situ, no idea to what limits though, the cabin roof is not a huge radius. 

 

 

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28 minutes ago, waterworks said:

No and maybe. The spacing of the framing would have to match the panels as they can't be cut and they can be curved in situ, no idea to what limits though, the cabin roof is not a huge radius. 

 

 

On a building project with large rectangular surfaces to be insulated, the proportion of the area that may need less effective insulation at edges, joints, around penetrations etc will be a small percentage of the total, and won't much affect the overall insulation effectiveness. On a boat with smaller areas, irregular shapes, fitting around windows/portholes, dealing with hull penetrations etc. the areas which will have to use some other insulation will represent a much larger proportion of the whole, with the result that the overall effectiveness will be much impaired. And so the whole thing will be much less cost effective.

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