The Philippine Indigenous Outrigger Boat: Scaling Up, Performance and Safety

The traditional indigenous double outrigger crafts, called banca boats, of the Philippines vary in size from the very small 4 meter single crew paddle boats to large 50 meter fishing vessels and passenger ferry boats. Regardless of size, the same construction techniques are used by native boat builders with wood as the main building material. Many hull forms, particularly economically important fishing boats, have been scaled up, resulting in problems related to the availability of wood for construction, safety at sea, and performance. Model experiments on craft performance show the hydrodynamic characteristics of the double outrigger form and describe characteristics important for design, construction, and operation of the crafts. The presence of outriggers has a definite effect on the heave, pitch, and roll motion of the craft as compared to the hull without an outrigger. Data analyses of maritime incident reports show a high percentage of capsizing by these motorized banca boats, highlighting the need for some regulation of their design and construction. Other concerns related to fisheries as being the main area of use of these boats are further discussed.