On July 20, 1999, U.S. Patent No. 5,294,732 issued to Dennis Olsen on an In-Line Skate Sail:

The idea of using a sail on skates was not a new one, even if Mr. Olsen’s particular construction was new. Fifteen years earlier. U.S. Patent No. 4,489,957 issued on a Tool for Sailing with Skates etc.:

U.S. Patent No. 4,311,324 issued on Skating Sails

U.S. Patent No. 4,978,140 issued on a Hand-held Skate Sail:

U.S. Patent No. D613360 issued on a Multi-purpose Body-sail with Swallow Tail:

U.S. Patent No. 7,726,694 issued on a Personal Sail Assembly and Method for Use in Conjunctions with a Mobile Device: