Read the dictionary definition of hydrofoil. All definitions for this word.
1. a speedboat that is equipped with winglike structures that lift it so that it skims the water at high speeds
1. the museum houses a replica of the jet hydroplane that broke the record
2. a device consisting of a flat or curved piece (as a metal plate) so that its surface reacts to the water it is passing through
1. the fins of a fish act as hydrofoils