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Boat Stretching enquiry


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Hi all! I'm new to this forum.

I've joined to inquire about boat stretching as we're considering getting our narrowboat increased from 50' to 61'. We realise this makes a couple of canals off-limits – it's more the technical side that we are interested in – pitfalls and things we should be considering/asking first.

We'd also appreciate any recommendations you might have for reputable companies to do the stretch work.

Many thanks,

Vickie

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I've thought about it, I suppose I still am, but the biggest hurdle for me would be needing a new, more powerful engine/gearbox.  I think our prop would be big enough for a lengthened boat but that's something else to think about - if you needed to increase the prop diameter have you got enough clearance?  

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Are you absolutely sure about lengthening? I can imagine a stretch, electrics, plumbing, repaint and engine swop could cost you towards £20,000.

Why not consider selling your boat and buying another the length you want? Perhaps consider a 57' length. There are compelling reasons for this size especially if you are considering going up north.

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Welcome aboard. 

Thought about doing this myself but it would have necessitated the need for a new engine meaning it would be less costly and less hassle to just simply buy another boat. Had a quote for a new Beta Marine 43hp engine to be installed and that alone was £12k. Had I pursued it, I'd problably need to upgrade/replace:

- Water pumps x2 (£180 without labour)
- Eberspacher / Webasto replacement for bigger unit (£1000?)
- Radiators / plumbing (£????)

Not to mention a repaint (£7000+ otherwise it would look untidy) and as it would have been out of water, it would have been silly not to get it blacked. It didn't take long until I started seeing the pound signs!

Also, if you're in a marina, it may be worth checking the costs for a 61' boat. At a marina near me, someone with a 61' footer boat would pay the same rate as someone with a 70' boat, whereas someone with a 60' boat would pay substantially less. 

I would recommend R W Davis & Son Ltd for this kind of work. They have a sound reputation, have been around for decades and build boats themselves. They know what they're doing. As it's quite a major undertaking it's probably best to get the work carried out by a reputable yard even if it does mean paying a little more for it to be done. Doubt there's anything worse than having a wonky boat!

 

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1 hour ago, Neil2 said:

I've thought about it, I suppose I still am, but the biggest hurdle for me would be needing a new, more powerful engine/gearbox.  I think our prop would be big enough for a lengthened boat but that's something else to think about - if you needed to increase the prop diameter have you got enough clearance?  

why?

it is quite possible that the boat will travel just as fast with the same engine and prop - I would suck it and see.

 

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1 hour ago, Neil2 said:

I've thought about it, I suppose I still am, but the biggest hurdle for me would be needing a new, more powerful engine/gearbox.  I think our prop would be big enough for a lengthened boat but that's something else to think about - if you needed to increase the prop diameter have you got enough clearance?  

We've checked that the engine and gearbox will suffice, so all is well on that front thanks. :)

 

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1 hour ago, Peter-Bullfinch said:

Are you absolutely sure about lengthening? I can imagine a stretch, electrics, plumbing, repaint and engine swop could cost you towards £20,000.

Why not consider selling your boat and buying another the length you want? Perhaps consider a 57' length. There are compelling reasons for this size especially if you are considering going up north.

We've looked at changing boats, but none were patch on the build quality and condition of our own.
We've also looked at having a butty built, but after much investigation, we've decided that keeping our 'known quantity' and getting it lengthened is the way we'd like to proceed.

There are only two canals we can't use with a 61' boat, the rest of the network is accessible (we're currently on the Lancaster at the most northern point :)).

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It's odd how a subject like this suddenly turns all boat owners into sensible financial managers.

If the end result is exactly what you want, it really doesn't matter what it costs.  I know a couple who had a 55 footer built new, fitted out, then decided it was too small so they almost immediately had it stretched to 65'.  the eventual cost was obviously considerably more than if they had commissioned a 65 footer but they got what they wanted in the end.

8 minutes ago, Murflynn said:

why?

it is quite possible that the boat will travel just as fast with the same engine and prop - I would suck it and see.

 

It's possible, I suppose with a 50 footer you may already have enough engine.   We're only 45' though and I think the engine (Bukh DV24) isn't up to pushing (and stopping) another ten feet of boat. 

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1 hour ago, RichM said:

Welcome aboard. 

Thought about doing this myself but it would have necessitated the need for a new engine meaning it would be less costly and less hassle to just simply buy another boat. Had a quote for a new Beta Marine 43hp engine to be installed and that alone was £12k. Had I pursued it, I'd problably need to upgrade/replace:

- Water pumps x2 (£180 without labour)
- Eberspacher / Webasto replacement for bigger unit (£1000?)
- Radiators / plumbing (£????)

Not to mention a repaint (£7000+ otherwise it would look untidy) and as it would have been out of water, it would have been silly not to get it blacked. It didn't take long until I started seeing the pound signs!

Also, if you're in a marina, it may be worth checking the costs for a 61' boat. At a marina near me, someone with a 61' footer boat would pay the same rate as someone with a 70' boat, whereas someone with a 60' boat would pay substantially less. 

I would recommend R W Davis & Son Ltd for this kind of work. They have a sound reputation, have been around for decades and build boats themselves. They know what they're doing. As it's quite a major undertaking it's probably best to get the work carried out by a reputable yard even if it does mean paying a little more for it to be done. Doubt there's anything worse than having a wonky boat!

 

I can see why you chose not to – that all adds up!

Our engine and gearbox have been checked and are powerful enough to cope with the 61' length.
We were about to have a heating system plumbed on the 50', fed from a stove back boiler. So the extra radiator/installation shouldn't be too scary and the back boiler is plenty large enough to heat all rads. Hot water will continue to be fed from a Morco gas boiler.

The beauty of stretching the existing is it gives us the opportunity to alter the layout, improve and increase the existing somewhat jaded facilities, which we were intending to do in the near future anyway. We can also add in a good sized office area – which is what the butty idea was for in our initial thinking. We both work from home so this bit is important.

Many thanks for the recommendation, we'll follow that up. :) 

 

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11 ft  extra will not make any difference to engine/ prop/ gearbox, it might even be faster, but having done a small water bug stretch I'd forget all about it 

do as others have said buy one the length you want,Itl cost more to stretch and fit out than selling yours at a reduced amount to sell quick ,and putting it towards one that's right

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3 minutes ago, Crow said:

11 ft  extra will not make any difference to engine/ prop/ gearbox, it might even be faster, but having done a small water bug stretch I'd forget all about it 

do as others have said buy one the length you want,Itl cost more to stretch and fit out than selling yours at a reduced amount to sell quick ,and putting it towards one that's right

How much do you think it would cost to add 10ft and fit out, in a straightforward area like the saloon. Kedian charge £700 a foot for adding the steelwork with a coat of blacking and primer, as appropriate, so £7k before fitting out.

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Then ,transport costs 2 ways.+ a crane.   Unless your near a yard.   £700 / ft  well ,  labour / overheads and insurance are always going up so is steel plate,plenty of people use him so that means a lot

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11 hours ago, Richard10002 said:

How much do you think it would cost to add 10ft and fit out, in a straightforward area like the saloon. Kedian charge £700 a foot for adding the steelwork with a coat of blacking and primer, as appropriate, so £7k before fitting out.

that pricing doesn't make any sense to me.  I would have expected to receive a quote like: £5k plus £500 per foot.  After all, most of the work is preparing to cut, cutting, and matching up the new steel at both ends, which is all part of what should be a fixed sum.

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3 minutes ago, Murflynn said:

that pricing doesn't make any sense to me.  I would have expected to receive a quote like: £5k plus £500 per foot.  After all, most of the work is preparing to cut, cutting, and matching up the new steel at both ends, which is all part of what should be a fixed sum.

I tended to agree with you -- then I thought about it and presumably most of the 'stretches' are round about ten feet, give or take. Much less than that would not be worth doing in the first place, and much more would be impracticable, so if the company bases its fixed costs on a ten-foot insert it will be there or thereabouts anyway!

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12 hours ago, Crow said:

11 ft  extra will not make any difference to engine/ prop/ gearbox, it might even be faster, but having done a small water bug stretch I'd forget all about it 

do as others have said buy one the length you want,Itl cost more to stretch and fit out than selling yours at a reduced amount to sell quick ,and putting it towards one that's right

How do you some to that conclusion?  Seriously, I'm, intrigued.  

Two members now have suggested that stretching a boat by 10' might make it faster.  If I thought I could make my boat more efficient through the water by adding another 10' and keeping the same engine/transmission I would go for it without hesitation.  But I'd like to hear the reasoning behind it. 

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40 minutes ago, WotEver said:

Nicely summed up within the article...

 

 

I love how you selectively quote. Perhaps a visit to Specsavers is due? :P

The article wasn't summed up by saying "It's total bullshit". What the article actually said was: “It’s total bullshit,” is how one designer friend of mine, Jay Paris, puts it. For in reality many boats, even those with honest-to-God displacement hulls, can easily exceed their nominal hull speeds.

The article was actually summed up in one of the final paragraphs: So the bottom line is that a boat’s hull speed is not necessarily its actual maximum potential speed. Probably it is more accurate to say that hull speed represents a minimum maximum figure. It still provides a useful rough estimate of how fast you can reasonably expect a boat to go...

Note that neither parts of the article quoted above suggest that the correlation between a boat's waterline length and its hull speed is incorrect, which is what we were talking about.

Edited by blackrose
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