A Bira wooden boat is typically framed in bitti (vitex), planked and shod below the waterline with dense ulin ironwood (kayu besi), and decked and finished in teak (jati) – all fastened with hardwood dowels rather than nails. The timber choices are not decoration; each wood is where it is because of what it does in seawater.
Bitti (vitex) for frames and floors
Bitti is tough, slightly flexible and holds a fastening well, which makes it the standard for frames and floors – the internal skeleton that has to bend with the sea without splitting.
Ulin ironwood for keel and underwater strength
Ulin, the Bornean ironwood known locally as kayu besi – literally ‘iron wood’ – is so dense it barely floats and resists rot and marine borers. It goes where punishment is worst: the keel and the planking below the waterline.
Teak for decks, houses and interiors
Teak’s natural oils make it stable and weather-tolerant, so it decks the boat and finishes the houses and interior where looks and comfort matter.
Where the wood comes from
- Sulawesi and inter-island sourcing, increasingly from further afield as local old growth thins.
- Legality and permits – the responsible builds document origin, because dwindling old growth makes provenance a real issue.
- Seasoning and moisture control on a humid coast, which decides how the hull ages.
Fastening that holds without steel
- Hardwood dowels (pasak) swell with the planking and never corrode, so the joint tightens in service instead of rusting apart.
- Plank-on-plank edge fastening builds the shell as one flexing structure.
- Caulking, bedding and antifouling keep the seams tight and the underwater timber protected.
Materials and classification
- BKI scantling expectations set minimum timber dimensions for a classed wooden hull.
- Documentation an owner should collect during the build – species, origin and the fastening schedule.
Discuss a materials specification
Timber grade, sourcing evidence and the fastening schedule belong in the build contract, not in a verbal promise; the desk prepares this specification with the yard before keel-laying. See how it fits the wider build on the build-process page, the heritage behind the method on the heritage page, and the certification path on the design and naval-architecture page.
Discuss a materials specification or email sales@komodoluxury.com
Frequently asked questions
What wood is a phinisi made of?
Mainly bitti (vitex) for frames, ulin ironwood for keel and underwater structure, and teak for decks and interiors, joined with hardwood dowels instead of nails.
How long does the timber last?
Well-maintained ironwood and bitti hulls routinely serve for decades; longevity depends on seasoning quality, caulking upkeep and regular antifouling rather than the wood species alone.
Is the timber legally sourced?
Reputable builds document timber origin and permits. Buyers should require sourcing evidence in the contract – something the desk includes in its standard materials specification.
Can a wooden boat get BKI class?
Yes. Biro Klasifikasi Indonesia surveys wooden passenger and charter vessels; scantling approval and survey coordination are arranged during the build rather than after launch.
Why wooden dowels instead of steel nails?
Dowels swell with the planking, do not corrode in seawater, and let the hull flex as one structure – a key reason beach-built hulls survive tropical service.