Origami steel boat with one plate

I recently discovered this interesting method of metal hull construction.

Question is: how efficient (or inefficient) would be a hull built using a single not cutted plate joined in half at the front and just "flattely" closed with a simple straight transom?

And since a picture is worth thousand words I attached some image of the idea (just transom missing)...

The construction would benefit both from less cuts and less soldering, and also aesthetically I like this resulting curved lines.

PS: differently pushing or pulling the top borders at various sections one can have some control of final hull shape

 

Theres a lovely thread on this very subject over on cruising anarchy.( Origami Boats).

Not for the faint hearted, but Mr origami himself,Brent Swain, is participating.

 

I think that the shape you show would make a lousy boat. It is interesting to try to develop a hull out of a single flat sheet. However, that should not take the place of good design.

 

"Good design" for what, on what basis should we evaluated the design. You can not tell whether a design is good or bad if you do not know the goals the designer wanted to achieve.

 

Oh, maybe you missed it. Good design for a boat.

 

Who wants to talk about good designs?: This really is a good design.

 

Looks like it should have desent initial stability.

 

Probably. Its problem should be the structural stability, and many other deficiencies.
Could anyone think to do that is to design boats?.

 

Some boats just sorta happen.

Apparently.

 

This sort of thing has been tried and the usual problems are related to getting reasonable shapes without a few more cuts in the sheets. Structural issues aside, the basic shape you've "discovered" produces a hull with a very fine entry, which doesn't hold up much and a progressively warped bottom to the transom. Though this can somewhat mimic a sea skiff like shape, the major problem is the transition from the forefoot to the after sections. This area usually requires a fair bit of "blending" to get it right, for both sail and power hull forms. You might be able to force some shape into these areas with a torch (requires pretty heavy plate stock), possibly some bulkheads, but generally it's wiser to work out what these shapes should be prior to bending.

In terms of you question about efficiency, well this is calculated based on the goals of the boat (SOR) and these help define the shape choices, you need to live with. There are ways to bend up plate, into a much better boat shape, though you'll have to live with some chines.

 

Bending a hull into shape is about 2% of the hull problem. Its like potential boatbuilders who 'estimate' the cost of building a hull, and totally forget about the other really high costs.

For example, I recently sent back a set of plans that only provided the developed hull panels, without the station dimensions.

Sure, the panel sheets would have developed into a reasonable hull shape, but then I was left with having to calculate the bulkheads and stringer dimensions individually to suit the hull, whereas if I could just cut the stations to shape, mount the stringers and fasten the hull panels onto them directly, I would avoid a lot of extra measuring and trial fitting work.

Likewise, if you fold a sheet of metal, without designed stations to fit it over, you have to retro-measure the stations etc. If you pre-calculate the stations and stringers, its really not going to save you time/money by having an instant fold skin to fit to them, as cutting out sheet steel is just a short plasma flame away.

The 'origami' methodology has a lot of hidden 'gotchas'. One previously mentioned is that hull shape efficiency and aesthetics becomes sacrificed for the build method.

 

One piece or welded steel is same strength.

So why bother with a strange hull shape when you can choose from thousands of hulls that were built and their performance is known?

 

Just as aside: I've wondered what an artfully minded home builder could achieve with a large English wheel, planishing hammer, shrinker/stretcher etc.

Granted, most steel boats aren't meant to be works of art (these tools do well with aluminum, but I'd be wary of unnecessarily work hardening that metal).

My all time favorite car, the Chrystler GS-1, from which VW copied the lines of the Carman Ghia, was made by numerable hammered steel plates, welded together, and the result ...

 

Put a transom on it and it will float. But even at that it is a long way from being a good boat. You will need stiffeners -more of them than if you designed a chine boat. The reason is that your hull is entirely a simple conic. It has no resistance to being a tighter conic or a flatter conic. By the time you get to a hull stiff enough to use I think you will have done lots of cutting and welding -to the point there is little or no advantage.

The next reason there aren't many boats built this way is that it has no ability to optimize the hull to reduce drag. The only parameters are length and transom dimensions. There is no rocker so the transom will drag severely at low speeds. The bow is shaped to push water out, not under for lift -not good for planing.

There seem to be several differing techniques and terms being thrown out -they are VERY distinct.
-origami -only uses folding, no cutting and joining
-buterfly -cut chines that end in the same piece of flat stock to develop shape -mostly conic shape but local 'torturing'.
-tortured -build from flat sock but violating the conic to give more desirable shape and increase stiffness
-standard 'developed' -pieced together from conics held in shape by attachment to other conics

 

The Native Americans (American Indians) were building boats with the canoe general configuration hundreds of years ago. They used the bark from Birch trees for the skins......Not exactly an origami boat but very nearly so. The method worked alright for them.....