RW. Give the lock a squirt of Corrosion Block. You’ll find the lock and internal tumblrs will love you shedding the water and grunge that magically grows on anything on a boat. I have a cheap master lock that I gave a dousing a year ago last spring. It had been on the boat for 3 months and showing signs of needing to be replaced. Cleaned up the spots of rust and salt deposits. It just finished a second season in working order. Key slides in and out like new.