Plastic duck Punt - manufacturing costs

dylanwinter

dylanwinter

Well-Known Member
Joined
28 Mar 2005
Messages
12,954
Location
Buckingham
www.keepturningleft.co.uk
I have a little sportyak dinghy

http://www.bicsportboats.com/products/sportyak,3,49.html

the little thing is made out of some sort of tupperware

It is an tough as old boots and gets its stiffness and floatation from the double skin

does anyone know enough about manufacturing to tell me if it would be possible to make a double skinned plastic duck punt out of the same material

and how much such a thing might cost

the punt is 15 foot long, three foot wide and 15 inches deep

it sails like a witch, is the most wonderful fun, it can be sailed, sculled and canoed, car topped and is astonishingly stable

I have no plans to throw any money at such a project but I am really enjoying sailing it and was just curious about the costs

Dylan

http://youtu.be/hgGCH7gaGLU
 
Sportyaks, etc, tend to be rotationally moulded. I think there might be technical limitations making something 5m long rather difficult to rotationally mould successfully. No reason why a duck punt couldn't be cheaply made in GRP though.
 
I know the Yaks, good but have seen them go brittle - presumably U/V and / or age - and break up, the initial stages exposing the foam, can't remember if it's proper closed cell so won't soak up much; think it is.

I'm no plastics expert, but I'd imagine one-offs would be entirely unsuited to this material, as 99& of the costs are tooling ?
 
not a one off

Seajet said:
I know the Yaks, good but have seen them go brittle - presumably U/V and / or age - and break up, the initial stages exposing the foam, can't remember if it's proper closed cell so won't soak up much; think it is.

I'm no plastics expert, but I'd imagine one-offs would be entirely unsuited to this material, as 99& of the costs are tooling ?
Click to expand...

Not really thinking of a one-off

just curious as to how cheaply you could make these things

the yaks are about £250

wave-skis seem to retail at about the same price

A duck punt is longer but a much simpler shape

internal fittings for a plastic duck punt would be no more than the mast partner - the mast step could be part of the mold

it would also tow more easily than a dinghy

Dylan
 
Being basicallt flat panels and grp not very stiff un less thick or with stiffners the punt could turn out too heavey,Its an ideal boat for plwood construction.
 
sport yaks not grp

mogy said:
Being basicallt flat panels and grp not very stiff un less thick or with stiffners the punt could turn out too heavey,Its an ideal boat for plwood construction.
Click to expand...

sport yaks and most wave skis are made of some other sort of plastic and are not GRP

grp would be pretty heavy

the thing is that most people cannot be bothered to build a boat themselves

even though these little things are incredibly easy to throw together

D
 
mogy said:
Its an ideal boat for plwood construction.
Click to expand...

dylanwinter said:
sport yaks and most wave skis are made of some other sort of plastic and are not GRP

grp would be pretty heavy

the thing is that most people cannot be bothered to build a boat themselves

even though these little things are incredibly easy to throw together
Click to expand...

The "other sort of plastic" is roto-moulded, I think polyethylene. The problem with any sort of moulding like that is getting the thing out of the mould afterwards, which limits the possible shapes. I don't really know how much they can do with multi-part moulds etc, but it may be that the Dylan Duck Punt is just the wrong shape to be efficiently roto-moulded. As Mogy said, it's an ideal boat for plywood.

Take your point about people not building them themselves. Dunno how cheaply you could semi-production-line build them by hand. Perhaps kits of pre-cut parts as a halfway house? On the other hand, tooling for plastic moulding has a high up-front cost, so if someone were doing this as a small business (never going to be particularly high demand) then moulding might not make sense anyway and a few woodworking tools mean much lower startup costs.

Pete
 
prv said:
The "other sort of plastic" is roto-moulded, I think polyethylene. Pete
Click to expand...

+1

In my previous guise as a windsurfer some 15 years ago , they made windsurfers out of this stuff for the very reason Dylan quotes - tough as old boots... repair it with a soldiering iron... we use to call it washing up bowl plastic... :D

The downside was a certain lack of stiffness - the good manufacturers got around this by including longitudinal carbon fibre strips inside the board... and weight....

I would think the DP would weigh at least two times as much made of this stuff..
 
They are polyethylene. Generally they will be heavy for their size. The Bic tenders are very popular on the lake as tenders. The plastic is quite soft and the bottom rubs out pretty soon. They often crack as well. Whilst you can weld them with milk cartons it's a bit hit and miss and nothing else sticks.
Most roto-moulded boats and dinghies rely on double curvature to provide stiffness. I can't see a duck punt being very true to it's origins once it's been adapted for this material.

Ply is probably the best material. As you say, people can't be arsed. Perhaps a kit of parts and the option of professional assembly would be the answer to marketing them.
 
I'm afraid I get the strong impression that people nowadays expect you to provide the boat at less than kit price, drive it to their house, assemble it for them while they watch TV, then take them for a meal afterwards...oh and give a 10 year guarantee.
 
Seajet said:
I'm afraid I get the strong impression that people nowadays expect you to provide the boat at less than kit price, drive it to their house, assemble it for them while they watch TV, then take them for a meal afterwards...oh and give a 10 year guarantee.
Click to expand...

Hmm, you could be right, I don't think the Mirror dinghy kit could have taken off if it had been developed recently. Definitely a boat of its time. How miuch is a Mirror kit today? Hmm, its over a grand just for the hull kit. I reckon you could knock that back to 6-800 squid for a duck punt kit plus whatever for an Oppy rig - or at least a cheapo clone.
 
I am sure you are correct

Twister_Ken said:
The b*gger with any mould-made product is the cost of making the mould. No idea what a DP mould would cost, but you could probably buy several Slugs for the price. So you've then got to amortise the mould cost over the production run, which is going to be how many?
Click to expand...


I am sure you are correct. In the short term I think that they are so simple to build that they will spread through builders

but I think that the concept of a tender that sails as well as this and in such shallow water - which is where you would have it.

Obviously it would not be as good as a stiff tender or a big inflatable. But you do see people on big boats with canoes on deck

this is a canoe that sails

and one made out of plastic that requires no maintenance would be great

you are right though

it will not happen

Dylan
 
Ply beats plastic any time for stiffness and weight. Prob is production cost and moulds (plastic)
Outfit in the US identified a lack of use for some big injection moulding company who made crates. They were season limited. So why not use your down time to make tenders? And size them to fit in containers with the seats removed so they nested. Needed big investment in moulds. Plus big marketing. I may be wrong, but I havn't seen too many of them about.

I would love the idea of cheap kits. My father produced many. But there does not seem to be a market in the modern world. Jordan boats do ply kits, and I wish them well. Still a small market.
We are back to the discussion about building verses sailing. Far cheaper to buy an old boat nd go sailing, than build one and sail several years(or never) later...
DW
 
that is true

DownWest said:
Ply beats plastic any time for stiffness and weight. Prob is production cost and moulds (plastic)
Outfit in the US identified a lack of use for some big injection moulding company who made crates. They were season limited. So why not use your down time to make tenders? And size them to fit in containers with the seats removed so they nested. Needed big investment in moulds. Plus big marketing. I may be wrong, but I havn't seen too many of them about.

I would love the idea of cheap kits. My father produced many. But there does not seem to be a market in the modern world. Jordan boats do ply kits, and I wish them well. Still a small market.
We are back to the discussion about building verses sailing. Far cheaper to buy an old boat nd go sailing, than build one and sail several years(or never) later...
DW
Click to expand...

I agree with you

- most of the way that it is

better to buy a cheapo second hand dinghy for £300 and go sailing

but that is not always the case

I built a GP14 when I was a teenager and se sailed it as a family for 20 years

I also built a 15 foot coble

took me six months

sailed it a week and it sits in the garden unloved and untouched

the punt is just seven days

and it is a unique sailing experience

it is also a car toppable boat that has been developed for a big man to sail

it needs the big man ballast to stay afloat

there is nothing comparable on the second hand market

Dylan
 
A 15' tender is a beggar to stow or tow I would guess. Even if designed to be halved & nested, it will be 7-8' long.

I have a wooden sailing dink (about 9' long) all the spars,sails & a set of oars stow inside, but I couldn't stow it aboard & towing a ply dink is not always a good idea. It has sat in the stable for the past 10 years. I used to piggy back it inside the inflatable for towing so it didn't matter if it rammed me. It also meant I had two dinks at anchor - vital when you have 2 teenagers aboard.
 
You must log in or register to reply here.

Share this page

Top