Air Traffic Control Fully Certified; Flight Crew Private
Flight Crew Last 90 Days 65; Flight Crew Total 304; Flight Crew Type 129
Situational Awareness
Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
General None Reported / Taken
Aircraft; Human Factors
This was my final landing after a week-long trip; I was coming home. As I was fifteen miles out; I received my first ATIS; winds were 080-110 @ 7kts. When I was ten miles out I listened to ATIS again; report was much of the same but winds were now at 10kts. I lined up on final; everything was normal. I landed with my main gear on the numbers; my nose gear shortly landed after that and I put my flaps up and carb heat off. As I was rolling out; my airspeed was slowing rapidly and I begin to lightly apply even brake pressure; as I have done thousands of times before. However; as soon as I [applied the brakes]; the airplane takes a severe turn (about 45 degrees according to tire marks) to the right. At this point I was traveling about 30kts and headed directly towards the marsh. I knew at this point; going into the marsh was inevitable. Instead of over-correcting and potentially flipping the airplane; I tried to keep the plane level; cut mixture and fuel pump; then I braced myself for impact. When I came to a stop; I immediately exited the aircraft and walked to FBO to call authorities.
PA-28 pilot reported losing directional control on the landing roll for unknown reasons.