Pinisi Boat Hull Structure

In prior years, teak may have been one of the preferred woods to use for the structure, although locally it is considered rather soft and inferior. Since teak is not especially favored and is actually no longer plentiful, other tropical hardwoods are used. Presently in Indonesia, Ironwood and Bangkirai are preferred for boat structures.
Obtained from the low land forests of Kalimantan, Ironwood is locally called Kayu Ulin (eusideroxylon zwageri). One of the hardest woods in Indonesia, Ironwood has a specific gravity of 0.88 to 1.19...! Although quite heavy, it has excellent physical properties and is not vulnerable to termites or other tropical wood eating insects or fungus. Kayu Bangkirai (shorea leavifolia) is also highly favored. Slightly less heavy than Ulin, Bangkirai makes excellent planking, decking, stringers, and upper structure.  Many other tropical woods are locally used, most of which have proven to be inferior for one reason or other.
Built in the same way as

the Indonesian Perahu type of hull, Pinisi have always been assembled using wooden pegs to join the timbers. We would call the fasteners " trunnels" or tree nails.  The sequence of assembly is different than we in the West would ordinarily assume. First the keel is laid, then the stem and stern post are erected, as usual. Then however, rather than setting up the whole array of sawn frames or 'mold frames' these vessels are built by applying the planking first..!
First the planks next to the keel (the garboard planks) are fit and pegged to the keel. Then the next planks are pegged to the garboard planks using "blind" dowels along the edges of the planks. One by one, additional planks are added until there is the shape of a boat. This of course is all done by "eye" according to the experience of each master builder.  With the planking nearly completed, frames are fitted into the hull shell. The frames are pegged to the planks, to the keel, and to each other where the frame segments are joined. The frame butt ends either lap across the keel (Sulawesi style), or are joined to a floor member (more common in Kalimantan), depending on the tradition from which the individual boat builders have come.
This "planking first" approach may seem odd to our rigidly defined approach to shaping a ship in the West, but this is as the builders among the Indonesian islands have done it since no one knows when. This is very much the most common method used throughout Indonesian, Malaysian, and other South and Southeast Asian waters, and the method has served the people very well indeed.