Pictures (Barthel):

This tablet has been used as planking in a canoe. Originally it was owned by Puhi 'a Rona, a tuhunga tá of Hanga Hahave, whose house 'was full of tablets and [he] scindered them at the call of the missionaries'. (Routledge according to Fischer.) '...a man named Niari, being of a practical mind, got hold of the discarded tablets and made a boat of them wherein he caught much fish. When the sewing came out, he stowed them into a cave at an ahu near Hanga Roa, to be made later into a new vessel there. [Nicolás] Pakarati, an islander now living [ca 1919], found a piece, and it was acquired by the U.S.A. ship Mohican.'

The wood is Podocarpus latifolius and probably arrived as driftwood after an American or European ship. Barthel's pictures show 8 + 8 = 16 rows, but Fischer has 8 + 9 = 17. I guess there were more rows, as 17 is odd and unlucky.