@The Minmus Derp If you could also edit out the duplicate message, that would be great.
I did some intense calculating based off of the numbers @ProtoJeb21 provided for Tau Ceti e, and everything checks out. Through those calculations, I determined that Tau Ceti e's ocean should be 5,157 km deep, and the radius of Tau Ceti e's mantle and iron core should be 7,266 km. This is perfectly in line with what would be expected from an water-world. This means that Tau Ceti e's ocean will be about as deep as Earth's radius.