Final answer:
Percy Bysshe Shelley was the author who tragically died in a boating accident at age 30. His death occurred in 1822 when his boat capsized during a storm, and his body was cremated according to Italian law. Shelley's poetic works often explored themes of mortality and nature.
Step-by-step explanation:
The author who died in a boating accident at the age of 30 was the romantic poet Percy Bysshe Shelley. He lost his life in 1822 when he and a friend capsized during a violent storm off the Italian coast after working on the launch of a periodical called The Liberal. Italian law at the time necessitated cremation, so Shelley's body was burned on the beach, in a scene both tragic and remarkably poetic, echoing the themes found in his works.
Shelley's death was preceded by his poetic premonitions of drowning in his work "Adonais," cementing his legacy as a romantic poet preoccupied with themes of mortality and the tumultuousness of nature. His life and his artistic output were cut tragically short, yet his work continues to inspire and is studied for its lyrical beauty and revolutionary spirit.