HDPE Canal boat

[magnetman]

5 minutes ago, IanD said:

So why does it have a narrowboat hull shape, with a swim and uxter plate at the stern?

 

A houseboat can just be a rectangular box, cheaper to build and more space inside...

Because whoever put it together thought it was going to be an alternative to a steel canal boat. 

 

It isn't. Don't forget this is a prototype and part of what a company would call R&D. Apparently easily recycled. 

A houseboat would ideally be a catamaran.

[PD1964]

1 hour ago, shaun15124 said:

we also have recently got a a naval architect involved who has made numerous HDPE boats and will address certain issue 

 

with the canal boat builder, this gentleman was the one who had made the original (gypsy lady ) 

 

you have no need to say sorry you are entitled to your opinion and that is why I put this on here to get many different people's opioins on this 

with the hdpe i totally understand that there are differences in regards to steel and hdpe 

 

Just searched “Gypsy Lady” on the boat finder, unfortunately non of the builders are familiar names and I doubt are still in business. Maybe it was Eastern C/vans & Bts 

[shaun15124]

the gypsy lady was built by 

John Hawkins of D & D engineering 

 

the challenges we faced were 

 

the sheets we used were 3mtr long and 1.5tr and our challenge was how do we do this without it looking like a patchwork quilt 

Along with that how will a diesel engine work within a plastic boat? 

 

cooling, prop shaft exit, weight, the strength of the hull of the boat, and ballast also there are a lot of long flat sides

how would the roof react to expansion and contraction 

(heat of the sun and freezing temperatures|) 50mm or 2" over 12mtrs from freezing to around 20 C 

 

we needed curved edges on the boat mainly the back corners of the boat how can we achieve this on the bow of the boat 

we need this to make the boat aesthetically pleasing 

 

another challenge was how we fit windows to a plastic boat do we use safety glass as with most boats or can we use polycarbonate 

another issue was plastic is very slippy how can we overcome this for decking ( we used a product called safetech)

 

lot of people think HDPE cannot be painted however we have a primer with a chemical additive that bonds to HDPE 

making the floor was a challenge as the plastic has to be welded on both sides so no turning over 

we made jigs and formers for the oven for various parts of the boat 

 

the roof was partially designed to allow it to expand ( every 5c increase is equal to 1mm expansion per meter over 12mtr=from freezing to 20c 50mm)

we had to look at a simple steel structure to support the base we used an h section of steel beams and is a flat-bottomed boat we now thought we would have an issue with ballast as HDPE is very buoyant and floats 

we increased the underfloor area to allow for this 

 

as said previously we are looking at the best solution for ballast 

 

the advance I believe we have achieved so far has proved it is possible to build a boat of this size (of course there are still things to learn) with more investigation this should lend itself to electric propulsion 

also, a third of the weight of a steel boat needs less than half the power to push it forward 

never needing blacking every 2 years 

we have proved something of this size for a plastic boat can be made to look excatly like a traditional boat but this is environmentally  friendly 

 

moving forward hopefully we could make any size that anyone wished ( it could even just be a hull etc )

 

if anyone has calculations etc by all means il say this again you more than welcome to come to take a look at this for yourself as we are based in Leeds 

or even if we had a zoom chat to show you where we are at with it im open to everyone's help on this and appreciate all comments 

 

 

[MtB]

1 hour ago, shaun15124 said:

 

the roof was partially designed to allow it to expand ( every 5c increase is equal to 1mm expansion per meter over 12mtr=from freezing to 20c 50mm)

 

^^^ this ^^^

 

I think will turn out to be a deal breaker for plastic canal boats.

 

The boat expanding in length by 50mm (2") between winter and summer is going to play havoc with the interior fit-out. Doors will stop fitting, gaps will appear inside shower enclosures, unsightly gaps will appear in panelling and deckheads, gas and water pipes and cables will get stretched and snap.... etc etc.

 

Or worse if fitted out in summer, when the winter arrives and the hull tries to shorten by 50mm the interior fitting out might prevent it, leading to hull cracks and splits. 

 

Much of this can be designed out with a lot of care, but there will still I suspect, be a shedload of unanticipated consequences.

 

 

 

Edited February 3, 2023 by MtB

[MtB]

Expanding on this if you'll forgive the pun, it gets worse. 

 

In the summer sun the roof will get up to 40c or much more, and try to get 4" longer. At the same time, the hull will be sitting in water at say 15c and not expanding anything like as much. Will the plastic and the welds especially have the structural strength to cope with the stresses generated by such large differential temperature changes as the seasons pass? Or even just the days and nights? As the top of the boat changes with air temperature and the hull is held at the same temp by the water it is in?

 

 

[PD1964]

1 hour ago, shaun15124 said:

 

the advance I believe we have achieved so far has proved it is possible to build a boat of this size (of course there are still things to learn) with more investigation this should lend itself to electric propulsion 

also, a third of the weight of a steel boat needs less than half the power to push it forward 

never needing blacking every 2 years 

we have proved something of this size for a plastic boat can be made to look excatly like a traditional boat but this is environmentally  friendly 

 

moving forward hopefully we could make any size that anyone wished ( it could even just be a hull etc )

 

if anyone has calculations etc by all means il say this again you more than welcome to come to take a look at this for yourself as we are based in Leeds 

or even if we had a zoom chat to show you where we are at with it im open to everyone's help on this and appreciate all comments 

 

 

 Hi, not being negative but all you have done is built what looks like a Narrowboat shell out of Plastic.

 You have not built a working, tested and usable boat that has been proved to function, handle the conditions long term that people can use safely on the inland waterways.

  As has been said what are you going to do about ballasting?
  You say there is no engine, there’s also nothing else Skeg, Rudder/Swan neck, windows/door, cabin fittings, plumbing/electrics and everything else internally and externally to constitute a finished boat?????????

  You have a long way to go to get a finished, signed off complying boat that meets all the safety standards and compliance that would be of interest to the public.

  One question. How much has that shell cost to date? not just materials, everything including wages. How much for me to buy?

Edited February 3, 2023 by PD1964

[shaun15124]

the engine we have in this is 

 

is 60hp canaline engine and control panel 

 

 you're not being negative at all your correct we have done a shell which in the few weeks we are going to be re-fixing issue , then fitting out, etc 

 

we know we have a long way to go to get this in the water correctly and fitted out 

 

Edited February 3, 2023 by shaun15124

[IanD]

55 minutes ago, MtB said:

Expanding on this if you'll forgive the pun, it gets worse. 

 

In the summer sun the roof will get up to 40c or much more, and try to get 4" longer. At the same time, the hull will be sitting in water at say 15c and not expanding anything like as much. Will the plastic and the welds especially have the structural strength to cope with the stresses generated by such large differential temperature changes as the seasons pass? Or even just the days and nights? As the top of the boat changes with air temperature and the hull is held at the same temp by the water it is in?

 

 

Funnily enough I'm currently working on a similar problem right now on a *much* smaller scale (a hot silicon chip in a cool package) and the biggest problem is warpage -- so here the hot roof will try and expand but the cold baseplate won't, and the difference in lengths works out at about 5mm per meter with a 25C difference (which is perfectly possible), which is 17x bigger than steel -- so the length change is similar to steel with the roof more than 400C hotter than the baseplate... 😞

 

Since the baseplate and cold hull bottom sides are far thicker and more rigid than the roof, what's most likely is that the roof will buckle when it heats up -- or possibly the boat will go slightly banana-shaped with the centre raising up, though I suspect the hull is too rigid for this. Or maybe a bit of both when the cabin sides join in too... 😉

 

What is needed is some proper thermal/physical stress analysis, which as noted above is what a naval/marine engineer would do. Of course this either needs an expensive 3D modelling program (like we use) or enough expertise to do extensive hand calculations, neither of which a boatbuilder is likely to have... 😞

Edited February 3, 2023 by IanD

[MtB]

3 minutes ago, IanD said:

What is needed is some proper stress analysis, which as noted above is what a naval/marine engineer would do. Of course this either needs an expensive 3D modelling program (like we use) or enough expertise to do extensive hand calculations, neither of which a boatbuilder is likely to have... 😞

 

 

Intuitively, my prediction is welds will split rather than the boat going banana-shaped. And if below the waterline this could be an utter disaster. 

 

I suspect even proper stress analysis would unable to correctly predict (possibly imperfect) welds splitting. 

[magnetman]

Playground equipment or themed classrooms.

[IanD]

10 minutes ago, MtB said:

 

 

Intuitively, my prediction is welds will split rather than the boat going banana-shaped. And if below the waterline this could be an utter disaster. 

 

I suspect even proper stress analysis would unable to correctly predict (possibly imperfect) welds splitting. 

 

The welds won't split because the roof is in compression when hot not tension, and thin panels (like the roof) buckle under compression at far lower stress than they (or welds) break under tension (like the cabin sides). The hull is much stronger and stiffer than the roof and is in tension; this is a battle that the roof is guaranteed to lose... 😉

 

Before you ask -- yes I studied all this as part of my engineering degree, and work with problems like this (but *much* smaller) on a daily basis. Nowadays engineers faced with problems like this tend not to do extensive hand calculations which are difficult, time-consuming and error prone, they use CAD programs designed for the job which are far more accurate and less prone to error for complex structures (and can include weld stresses) -- for example Solidworks, which IIRC costs about £4000 per user... 😞

Edited February 3, 2023 by IanD

[shaun15124]

6 minutes ago, IanD said:

 

The welds won't split because the roof is in compression when hot not tension, and thin panels (like the roof) buckle under compression at far lower stress than they (or welds) break under tension (like the cabin sides). The hull is much stronger and stiffer than the roof and is in tension; this is a battle that the roof is guaranteed to lose... 😉

 

Before you ask -- yes I studied all this as part of my engineering degree, and work with problems like this (but *much* smaller) on a daily basis. Nowadays engineers faced with problems like this tend not to do extensive hand calculations which are difficult, time-consuming and error prone, they use CAD programs designed for the job which are far more accurate and less prone to error for complex structures (and can include weld stresses) -- for example Solidworks, which IIRC costs about £4000 per user... 😞

thank you for this 

and your feedback has been helpful on so many ways, (now can you pop up to Leeds and help 🙂 ) 

[IanD]

9 minutes ago, shaun15124 said:

thank you for this 

and your feedback has been helpful on so many ways, (now can you pop up to Leeds and help 🙂 ) 

 

You're welcome 🙂

 

I think you need to get somebody involved with the project who really understands these issues (like robustness and thermal stresses) and get some advice from them, because you're trying to do something pretty much new and there are always bear-traps lying in wait for you when you do this -- I should know. I've spent pretty much my entire professional life inventing better mousetraps and trying to spot unforeseen problems with them, thankfully mostly successfully... 😉

 

The further you depart from normal practice the higher the chance of problems like this cropping up, and it sometimes takes a fresh eye from outside to spot them, hopefully before they become a killer -- I've had this happen many times, it's *usually* possible to find a solution but it might need big changes to do it if the problems are big, which I think yours are... 😞

 

Unfortunately I can't really help apart from commenting on here -- and TBH some of the problems with an HDPE canal boat identified on this thread are pretty fundamental and not going to be easy to solve... 😞

Edited February 3, 2023 by IanD

[Jon57]

5 hours ago, MtB said:

Expanding on this if you'll forgive the pun, it gets worse. 

 

In the summer sun the roof will get up to 40c or much more, and try to get 4" longer. At the same time, the hull will be sitting in water at say 15c and not expanding anything like as much. Will the plastic and the welds especially have the structural strength to cope with the stresses generated by such large differential temperature changes as the seasons pass? Or even just the days and nights? As the top of the boat changes with air temperature and the hull is held at the same temp by the water it is in?

 

 

Crt will have to be informed about the additional length if it goes into the next license bracket.🤣🤣🤣

[booke23]

1 minute ago, Jon57 said:

Crt will have to be informed about the additional length if it goes into the next license bracket.🤣🤣🤣

 

Nah.....just measure it mid winter and say no more!

[IanD]

1 minute ago, Jon57 said:

Crt will have to be informed about the additional length if it goes into the next license bracket.🤣🤣🤣

 

Even better, if you moor it for hours with one side in the hot sun and the other in the shade it'll bend sideways and not fit in locks any more... 😉

[Jon57]

2 minutes ago, IanD said:

 

Even better, if you moor it for hours with one side in the hot sun and the other in the shade it'll bend sideways and not fit in locks any more... 😉

 

2 minutes ago, IanD said:

 

Even better, if you moor it for hours with one side in the hot sun and the other in the shade it'll bend sideways and not fit in locks any more... 😉

Could be good for winding without the winding hole then 👍

[IanD]

3 minutes ago, Jon57 said:

 

Could be good for winding without the winding hole then 👍

You'd have to get it pretty hot though -- maybe douse one side in petrol and set it on fire... 😉

Edited February 3, 2023 by IanD

[Jon57]

56 minutes ago, IanD said:

You'd have to get it pretty hot though -- maybe douse one side in petrol and set it on fire... 😉

Like I said earlier in this thread. A canal boat made from HDPE is a pipe dream 🤭

[magnetman]

A sewer tube.

[PD1964]

8 hours ago, shaun15124 said:

The advance I believe we have achieved so far has proved it is possible to build a boat of this size (of course there are still things to learn) with more investigation this should lend itself to electric propulsion 

also, a third of the weight of a steel boat needs less than half the power to push it forward 

never needing blacking every 2 years 

we have proved something of this size for a plastic boat can be made to look excatly like a traditional boat but this is environmentally 

 

 

 

 

6 hours ago, shaun15124 said:

the engine we have in this is 

 

is 60hp canaline engine and control panel 

 

 you're not being negative at all your correct we have done a shell which in the few weeks we are going to be re-fixing issue , then fitting out, etc 

 

we know we have a long way to go to get this in the water correctly and fitted out 

 

 You seam to be contradicting your previous posts.

 Why would you fit a 65hp diesel? these engines are normally fitted to Steel widebeams 60’x10’6” weighing around 30T when you said electric will work being a third of the weight and needing half the power, so why not an electric or a 30hp engine?

  Then you go on about a plastic boat being more environmentally, then your putting in a big Diesel engine?

  I don’t think you know what your doing and if I was your company I would not take this any further, until someone in your R&D department started doing some serious R&D into the overall concept. As at the minute a plastic boat with a huge Diesel engine in it, is not going to sell. Simple.

[Jon57]

28 minutes ago, PD1964 said:

 

 

 You seam to be contradicting your previous posts.

 Why would you fit a 65hp diesel? these engines are normally fitted to Steel widebeams 60’x10’6” weighing around 30T when you said electric will work being a third of the weight and needing half the power, so why not an electric or a 30hp engine?

  Then you go on about a plastic boat being more environmentally, then your putting in a big Diesel engine?

  I don’t think you know what your doing and if I was your company I would not take this any further, until someone in your R&D department started doing some serious R&D into the overall concept. As at the minute a plastic boat with a huge Diesel engine in it, is not going to sell. Simple.

Could end up as a nice planter in a shopping mall somewhere. Or Nice feature in a new development, bit like the boat Parvo in London without the history.🤭🤭

[PD1964]

40 minutes ago, Jon57 said:

Could end up as a nice planter in a shopping mall somewhere. Or Nice feature in a new development, bit like the boat Parvo in London without the history.🤭🤭

I would put the brakes on this concept project as of now, as it could run away with regards to expense and become a big White Elephant, @shaun15124 seams to know little about Narrowboats and also their adviser from D&D seams to be somewhat not up to current boat building practices with regards to electric motors??????

[magnetman]

I think a small trailerable narrow boat with outboard motor would have been interesting in this material. Maybe not very practical but interesting to have a look at. 

 

Is anyone making caravans out of this stuff? 

 

[Bod]

@shaun15124

Expanding roof..

I'm thinking,Landrover Safari roof type.

Top layer freely expanding, lower layer, with 2-4 inch air gap fixed and weather tight.

Shall have to think more about the sides...

 

Bod