On March 13, 1969, on the Bái Háp River, Kerry was in charge of one of five Swift boats that were returning to their base after performing an Operation Sealords mission to transport South Vietnamese troops from the garrison at Cái Nước and MIKE Force advisors for a raid on a Vietcong camp located on the Rach Dong Cung canal. On what body part was Kerry wounded on Mar 13, 1969