Did early hominids cross sea gaps on natural rafts?

Distributions of non-human primates suggest that some species have colonised across wide sea gaps. Many reports exist of natural rafts capable of transporting large terrestrial vertebrates across such gaps, including in Wallacea, and other data show that people can survive adrift for at least several days. Climatic and oceanographic features of this region are also consistent with the idea that natural rafts may have permitted Homo erectus to colonise Flores, and H. sapiens to colonise Australia. Speculations about linguistic or other skills based on the assumption that these hominids built watercraft should therefore be viewed cautiously.