If you haven't already done so, I highly recommend you use the "view all steps on one page" function.
Step 1: Idea Generation Phase
I saw these two hulls lying beside each other and half jokingly thought that they could be lashed together to create a ridiculous sailing craft of some sort.
Basically if you have some ingredients similar to these (unlikely), sit them a nautical distance apart and lay some sticks between them. Now you have the choice of either convincing anyone who is around that this idea could work, or just ignoring the laughter and getting on with it.
Step 2: Let the lashing begin
This fantastic system allowed us to quickly get the crossbeam and deck structure worked out to rough dimensions, while the flexibility and ease of adjustment allowed for fine tuning. The structure we came up with is fairly simple and the photos explain it well enough. Anything with reasonably substantial crossbeams between the hulls and a bit of diagonal bracing would probably work.
Step 3: Add More Sticks
Step 4: Rigging
Step 5: Painting
-Fast drying time
-Water clean up
-Poor adhesion to most surfaces
-Low water resistance
-Delightful nautical grey shade
-In my shed
All in all, perfect for a one day ndrua.
Step 6: Put it Back Together
Step 7: Sailmaking
Basically I bought a cheap tarp and cut in some slightly rounded edges to give it some camber. I folded these edges over and taped them with low quality duct tape to create a sleeve for the luff/leech wires to run in.
I had some stainless steel wire around which I used to make the mast stays and the luff/leech wires.
Step 8: Float Test
Step 9: Sailing trial
Step 10: Rig Modification
This is about as far as experimentation ever went with the One Day Ndrua. The boat was just too small and difficult to sail to be very good for anything much, but it was still heaps of fun. More boatbuilding Instructables are on the way.