The Subak was constructed from an old sheet steel fishing Zille and a discarded windsurfer connected as a catamaran. We carved a simple pole mast with no standing rigging from a 10cm square post left over from another project. The Chinese Lug, or Junk sail was made from locally produced cotton and died with coffee grounds left over from a local breakfast spot, Cafe Maier. The boom and yard came from former floor struts from a low stage. The battens were bamboo cut from a colleague's garden. Floorboards and front decking were assembled from old sheets of “Doka” plywood used for concrete formwork. The rudder and daggerboard came from a different type of formwork plywood.

We added extra walkway planks to enable a safer access to the outrigger. This also gave us a place to sit. The helmsperson sat on a discarded skateboard deck, stripped of its grip-tape.

The main safety calculation we made was to derive a value for the force that the sail would produce sideways if blown by storm winds. We then calculated what this force would correspond to as weight on the outrigger, either trying to lift it or sink it. These values were satisfyingly safe. The other main calculation we made was the depth of the main hull in the water with various loadings. With three people, propulsion gear, safety gear, food and camping equipment, we estimated 12 cm of depth. In practice we found that the weight distribution was moved forward causing the bow to sit more deeply than the stern. In this process we also calculated the complete weight of the vessel. This was important as we understood that the legalities on the Danube stated that a vessel under 250kg unladen weight did not need a motor and therefore no registration. This turned out not to be quite the case: see the Danube travel notes for details.

The mast support (so-called partners) were adapted to allow us to lower the mast for low bridges without having to dismount it completely. We were able to get under bridges as low as 4.2 meters without complete de-masting. Lowering and raising the mast was fast enough to be able to “shoot” a bridge when we had wind behind us. As the canals funnelled wind, we found that we either had wind from the bow or from astern. Auxiliary propulsion was obtained with simple oars or with the Yuloh. The Yuloh was rebuilt from a single large piece of larch after the Danube journey and proved to be effective. Emergency propulsion was with a 6-horsepower 2-stroke outboard motor.

  • resilients/subak_construction_notes.txt
  • Last modified: 2013-02-13 22:43
  • by alkan