The Hydrofoil from Dreamfall
In the real world, a hydrofoil is a boat with foils mounted beneath the hull that, as the boat picks up speed, develop enough lift to raise the vessel out of the water.
The 'hydrofoil' Zoë Castillo takes to Japan appears to function very differently. It has two pairs of wings, two propellers which are presumably for steering and supplemental to the main engines, and four passenger decks with what appears to be a cargo deck beneath them. The manual describes its function simply as "moving at impossible speeds close to the ocean surface, the hydrofoil connected us again with our relatives on the other side of the Earth."
There are similar vehicles in real world, called Ground effect vehicle. The most famous is Russian A-90 Orlyonok and Russian Lun-class ekranoplan. Lun Orlyonok
As has been pointed out by fans, the Dreamfall hydrofoil is really a Wing-in-ground craft.
Hydrofoil concept art.