Ertuğrul bilal: My best guess would be a people of South East Asia; I am tempted to assert Dayak; yet Aceh is better choice out of the hints you gave.
Note: I couldn’t help myself out of curiosity and cheated somewhat. The correct answer came along quite fast following a quick web search: Paiwan, an Austronesian people from Taiwan. That explains the statement regarding they are among best mariners of planet’s history.
Ertuğrul is a poster from Turkey. He’s quite good at languages. He’s of Laz ethnicity but I don’t think he speaks Laz.
He did a good job! Dayak and Acehese are not far. After all, they are close to the location, and they both speak Austronesian languages!
That explains the statement regarding they are among best mariners of planet’s history.
Exactly! They were the Lapita, the greatest mariners in history! They settled all of the Polynesian and to a significant extent the Micronesian islands. I don’t understand the settlement of Micronesia very well.
They also settled the coast of New Guinea, but there were already Papuans living there whom they apparently supplanted. They also settled all of Melanesia even though there were probably already people there. They settled the Philippines, Indonesia, Malaysia, you name it.
It’s not known what languages were spoken in the Philippines, Malaysia, Indonesia, or even Melanesia before the Austronesians showed up. I would assume that Papuan languages were spoken in Melanesia. Papuan languages may still be spoken in far eastern Indonesia, hence Papuan is a good choice for Indonesia too.
Howevever, I’m not aware of much if any substrate in Austronesian hinting at the languages that were supplanted. The Negritos of Indonesia, Malaysia, and the Philippines are obviously the indigenous people whose languages and ethnicities were supplanted by the Austronesian colonists.
However, all Negritos in this area speak languages Austronesian languages. Whatever their ancestral languages were – possibly Papuan as the Andaman Islanders appear to speak a Papuan language – were lost and replaced by the languages of the colonizers.
Even genetically, the Negritos of Malaysia and the Philippines are not different. Genetically, the Negritos of Malaysia resemble Malaysians and the Negritos of the Philippines resemble Filipinos. This is due to genetic swamping – the Austronesian colonists bred massively into the local Negrito populations, rendering the genetic similar in both cases.