Time of our lives 2: Boats

Tens of thousands of years ago, the idea of building different types of water transport started. Like log rafts, bundle (or boyant) rafts; and, log, plank, bark, hide, pottery, bundle, or basketry boats. It may have originated in one area. And, from there, ballooned out.

What are prehistoric boats?

The earliest log boat is dated to the eighth millennium BC.
There are only a few hundred log boats worldwide before 1500, though man rebuilt many. Perhaps there are some still at bottoms of bodies of water.

The earliest plank boat went to the five thousand years ago.
There are a hundred well documented plank boat and ship remains from before 1500.

There are no excavated examples of the other five basic types of boat: hide, bark, bundle, basket, or pottery.
No bundle or buoyed rafts; and

Only five documented log rafts. The earliest from Roman times.

How do you think elders got to south, central and southern North America 15, 16, or even 18,000 and more years ago? And what explains the lack of data for some of the most commonly known boats?

Our knowledge is also very much biased towards planked boats and ships.

It is also biased towards Europe. Why is this?