Not sure if this is of any interest or use but here is a mention of Kemp in Tarpon Springs which is close by boat to Cedar Key. This came from a book about Tarpon Springs
A few old timers remember “The Ballad of Hamilton Pinder”, set to an English ballad tune. It tells of a young Key Wester who was stricken with blood poisoning while on a schooner in the sponge trade. The captain, Henry Kemp, brought the lad to Tarpon Springs, where Dr. Albaugh pronounced him beyond help. Young Pinder made a godly end among kind people, and his mother took his body home for burial. Captain Kemp wrote the ballad.