Helm Exhaustion

A helms-person can safely pilot a ship for 8 hours a day. They can push on beyond that limit, at the risk of exhaustion.

For each additional hour of travel beyond 8 hours, the pilot must make a Constitution saving throw at the end of the hour. The DC is 10 + 1 for each hour past 8 hours. On a failed saving throw, a character suffers one level of exhaustion.