This is our pool (see pictures). It was here when we moved into our home. I know for certain this pool is at least 10 years old because I swam in in about 8 years ago before I moved into the home. We are trying to figure out what kind of pool this is and what kind of liner we need to order to replace the current one. I have been told that the pool is not a doughboy. I have also been told that I would need an overlap liner. Can anyone offer anymore information? We believe the pool is 21 x 41.