Thuyền thúng Coracle: solid bits and waterproofing

I've been experimenting with my scale model and trying to work out structural aspects I need to engineer for my paper coracle.

There are four challenges:
  1. The Rim: The best way to make the coracle is to first lay down onto a flat surface  a circular frame. This will become the circumference of the craft.  My problem is deciding what to construct the frame from. Due to my previous experience making puppets and masks, including some quite large puppets, I know that bamboo skewers lashed together make a very strong rod. So my plan is to (i)soak skewers (the cheapest and most accesshttps://www.telegrow.com/tienda/images/irrigation_pipe.jpgible form of bamboo as they can be purchased from any supermarket) in water so that they flex (ii)then insert the rod into agi-pipe tubing.(Agi pipe, irrigation tubing, is available from any hardware store).(iii) before bending the piping with the skewers inside into a circular shape at a preferred diameter.
  2. The Depth of the Rim: While one agi pipe frame should hold the bowl in place and shape I want a  very strong rim that will withstand a lot of battering -- such as from the working of a paddle. So I'm thinking I will need  4 such tubes lashed together and shaped into a circle or one pipe wrapped around four lashed skewer rods. I'm thinking that zip  plastic ties are the preferred binding both for the bamboo as well as for the tubes.
  3. Protection and Waterproofing: The original  Thuyền thúng  is simply a bamboo basket coated with resins or pitch. The British Isles coracle is canvas stretched over a frame and coated with tar. I have to be cognizant of paper's attributes and the fact that the 'walls' are built up layer by layer.So I can use choose to use marine paint or 2 pack epoxy. However, while the epoxy will strengthen and protect the 'hull' it doesn't so easily lend itself to touch ups, and re-coatings each year of use. So I am going to explore Deks Olje  which is a Saturating Wood Protector. You can also apply a gloss finish. However, I don't want the 'protector' reacting with my glue and causing either the layers to peel or the stiffness and structure to collapse.(I intend to experiment).
4.The need for a supplementary frame? Technically when working with paper-mache the paper has its own form and strength. Any skilled paper worker knows that  stronger  paper  gives solid results. So I'll be using Kraft paper which is paper produced  from wood pulp.  This is also why I use cellulose based wallpaper  pastes. But as any paper artisan also knows, when you layer the paper with structure in mind -- by criss-crossing the strips or layering them half and half over each strip -- you build in structure. I also always massage the paper layers with my hands pushing and tugging the wet  paper into place and merging the layers by applying pressure. If I was to then introduce a frame  structure as well by adding ribs to the coracle -- made from? -- I'd be running at cross purposes to the papier mache's internal logic and maybe introduce tear points. So I'm thinking that if I laid down bamboo skewers  running from the internal centre of the  bowl/hull I could then coat this net structure with further paper layers. I've done this before. This would make the floor of the coracle slightly corrugated. If I were to make up standalone structural ribs like the rim, they would not be easily integrated into the craft's internal structure and may tend to lift as they have to be added after the shape was made and the mould separated.

So --  it's back to the drawing board and the glue pot I go.


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