This is just one man's opinion, but as a PADI Instructor, I guess I'm entitled to it. I consider the Blue Hole to be an advanced dive.
I consider certification as an Advanced Open Water Diver to be completely sufficent and appropriate for this dive. It is my opinion that this dive is not appropriate for divers holding certification as Open Water Divers.
I'm not telling anyone what to do, but for myself, I think if one is intent on diving the Blue Hole and does not feel able to put forth the effort to become an AOWD, they would do well to stay very close to their Divemaster.
Keep in mind, though, that AOWD is a really fun course. It's mostly about experience. I encourage all divers with a commitment to safe diving to continue their education, for their own benifit and the benifit of those around them.
In Advanced one learns how to become more self-sufficent. In Rescue Diver one learns how to think beyond one's self and be helpfull to others in their time of need.
These are things responsible divers want to do. Diving is as safe as we make it.
[This message has been edited by Florian (edited 10-15-2001).]