Bring water to a boil in a medium-size saucepan; stir in grits. Cover, reduce
heat, and simmer 15 minutes, stirring occasionally.
Remove from heat, and stir in sugar and butter.
Gradually stir about one-fourth of hot mixture into eggs; add to remaining hot
mixture, stirring constantly. Cook over low heat until mixture thickens and reaches
160 degrees F (about 8 minutes).
Remove from heat, and stir in coconut and sour cream.
Spoon mixture into prepared
crust; cover and chill.
Garnish with sweetened whipped cream and maraschino cherries before serving.