Career
Born in 1848 in Ireland, Dempsey immigrated to the United States and joined the United States. Navy from Massachusetts. By January 23, 1875, he was serving as a seaman on the United States Ship Kearsarge. On that day, while Kearsarge was at Shanghai, China, he jumped overboard and rescued a shipmate from drowning.
On board the United States.S. Kearsarge at Shanghai, China, 23 January 1875.
Displaying gallant conduct, Dempsey jumped overboard from the Kearsarge and rescued from drowning one of the crew of that vessel.