Kerry was a Lieutenant, junior grade, running a Swift Boat detatchment on the Mekong River during the particularly rough period known as Operation Swift Raider, cutting Viet Cong/NVA resupply routes on the rivers.
Swift Boat personnel took a particularly high number of casualties; the boats were unarmored, noisy and thereby easy targets for ambushes and magnets for RPG and B-40 antitank rockets and heavy machinegun fire from fixed positions; the odds of a Swift boat crewman becoming a casualty during a normal one-year tour was around 75%. Getting wounded three times in four months and getting out before that liklihood was doubled may not have been the bravest thing Kerry ever did, but it may have been his smartest.
