you lack some brain cells, but that's fine.
THE thing is, hashing it 3 times is not safe as it can produce collisions
hashing a hash is as stupid as it sounds.
return from ntencrypt("bananas"): 153616851
return from ntencrypt("fsdghas"): 155976153
You failed
What heekzs presented was a theoretical example of what is known as a hash collision. Please read at least the first few paragraphs of this Wikipedia article, because what you posted is ignorant of it:
http://en.wikipedia.org/wiki/Collision_(computer_science)
That being said, using multiple iterations of a hashing method is not insecure in and of itself, and makes it more difficult to compute hashes since each hash iteration takes longer to calculate. The tradeoff is that this also slows down your server, which would not be necessary if your hashes were
salted properly.
The only time collisions would become a concern, which is highly unlikely due to the extreme unlikelihood of a collision ever occurring, is that if, by chance, one of the hashes in your sequence has a collision, then all of the hashes generated from that hash will also collide.
See also:
Key stretching