Airships of the sea

摘要

If you blow a lot of air bubbles under a ship, and keep them coming, "good things will happen", says Steven Ceccio, an expert on bubbles at the University of Michigan's mechanical-engineering department in Ann Arbor. When air is pumped rapidly out of small holes in a ship's hull, the swarming bubbles will quickly join together and coat the hull with a layer of air a centimetre or two thick. This reduces drag, because air offers far less resistance than water.