Hovercrafts: How Do They Work?
You have probably seen them at work, especially in the spring, clearing ice jams to prevent flooding. They move easily on water, over flats and even on land. But how do these amphibious craft that seem to fly above everything really work?
The air cushion under a hovercraft is created by two engines, each of which turns a shaft that drives centrifugal fans. These fans direct the outside air toward the bottom of the hull and inside the black skirt that is fastened around the perimeter of the hull with hinges. The loop skirt is made from reinforced neoprene (a thermoplastic synthetic rubber) under which is a segmented skirt made from fabric sections folded over each other and sometimes referred to as a finger skirt. Air escapes through the lower openings of these segments to lift the hovercraft. It is this lift phenomenon that supports and provides stability to the hovercraft.
In Quebec, the Canadian Coast Guard uses two hovercrafts: the CCGS Sipu Muin and the CCGS Mamilossa. Their ability to access areas that conventional vessels cannot reach make them especially useful for flood prevention, tending and removing buoys or maintaining aids-to-navigation, environmental responses, and search and rescue missions.
Marty Robitaille and Stéphanie Nadeau
Canadian Coast Guard