It checks the 8 nodes around & 1 below the gear for ice but it doesn't seem it cares if there is actually any water below the ice! My suggestion would be to simply change it to y-2 from y-1 and check for water instead of ice. That way it would actually require a lake/ocean with at least 1 ice above it where the hole is drilled.
P.S. Found a map generated one (I think) in a virgin forest with some ice on the ground. At first I thought it was put by a player but that's unlikely.
It checks the 8 nodes around & 1 below the gear for ice but it doesn't seem it cares if there is actually any water below the ice! My suggestion would be to simply change it to y-2 from y-1 and check for water instead of ice. That way it would actually require a lake/ocean with at least 1 ice above it where the hole is drilled.
P.S. Found a map generated one (I think) in a virgin forest with some ice on the ground. At first I thought it was put by a player but that's unlikely.