According to Wikipedia, Reed boats and rafts are interesting to me because its construction adds up to something that not only floats but is capable of transporting people over long distances thousands of years ago.

Peruvian Fishing Boats

Here is a photograph by Paul Kennedy, available from AllPosters, that shows these boats in action.

Fishermen Paddle Their Cabillitos De Totora Reed Boats Out Through Waves, Pimentel, Peru by Paul Kennedy

According to AtlantisBolivia.org, reed (totora) boats are made from two individual hulls or cylindrical cores which are bound together by attachment to a smaller central core using a single continuous rope in a spiral fashion thus forming a single united hull from the component reed cylinders.

Principles of Reed Boat Conduction from alantisbolivia.org

 

The Totora Reed develops at a depth of between 2 to 5 meters and sticks 3 to 4 meters out of the water.