Hollow boat model with two decks.
The back of this model is open.
Paper & size
When folding with a dual-colored paper, fold with the white side up when folding the first edges after pre-creasing (around 05:14 in the video). Then turn the paper over so the colored side is up and continue with the collapse.
When folded from a 35cm square, the model ends up 30cm long, 10cm in height and about 7cm wide.