Complex sentence: He launched a regatta in 1851, then unsuccessfully proposed starting a national subscription for France to send a yacht to the regatta around the Isle of Wight at which, on 22 August 1851, the schooner "America" won the trophy later renamed the America Cup.
Split into simpler sentences: He launched a regatta in 1851, then unsuccessfully proposed starting a national subscription for France to send a yacht to the Cowes Regatta. On 22 August the schooner "America" won the historic trophy later renamed the America Cup.