He made his first team debut for the club in a 1–0 victory over local rivals Hull City in the Football League Trophy in January 1998.
Ben was used as the club's reserve left back and was understudy to Tony Gallimore, Chapman only managed 2 appearances in both the 1999–2000 and 2000–2001 season and would have to wait until the 2001–2002 campaign before he started to have a regular run in first team affairs.
While playing for Grimsby, Chapman was responsible for ending the career of Scunthorpe United midfielder Peter Morrison during a pre season friendly in 2001.
[1] In July 2002 Grimsby captured Welsh International left back Darren Barnard on a free transfer thus resulting in Chapman's release from the club.
He signed for Boston United and became the team's captain, and was able to give his new teammates a helping hand as The Pilgrims avoided relegation from the Third Division.