The only reason I am interested in the "standards" is that it seems the primary criticism of the instructor is that he somehow violated them. But most of us don't know what "them" are. While most seem to accept that overweighting a student by 10 pounds is a problem, overweighting students seems to be a widely accepted norm that is practiced in many OW classes today. For some of the diving I do (working on the bottom) I normally overweight myself. I'm curious where and how the line is drawn, and by whom.
Similarly with instructor student ratios, I'm curious how the "standards" adjust for age and water conditions. I'm wondering how the "standards" ever go over a 1 to 1 ratio.
Here are some of the standards, related to ratios and supervision. Remember not to scroll down and say "4:1, he was withing that so he was okay". He was also required by the standards below to reduce that ratio so that he could immediately make contact with any diver needing assistance. For me, the only way I would know how to accomplish all those things is to take usually two participants and either hold them or their gear.
Ratios
You must apply continuous and sound judgment before, during and after the dive. It’s your professional responsibility to conduct a risk assessment by evaluating variables such as water conditions, temperature, visibility, water movement, entries and exits, ability of participants, certified assistants available, your and your assistant’s personal limitations, etc., to determine what ratio will fit the situation — reducing the ratio from the maximum if needed. Take into account changing variables and your ability to directly supervise and observe particpants. Reassess during the dive.
Participant-to-Instructor
Pool 8:1
Confined Open Water 4:1*
Open Water 4:1*
Additional OW Dive 4:1*
* May add a maximum of two participants with certified assistant.
** After participants have completed an initial open water dive with an instructor. If certified divers join Discover Scuba Diving participants, count the certified divers in the ratio and stay within the Discover Scuba Diving participant-to-instructor ratio.
Supervision
Do not leave participants unattended, either at the surface or underwater.
• Position yourself so that you or a certified assistant can make immediate physical contact with, adjust buoyancy for, and render assistance to, participants.
• Continually observe participants with only the brief, periodic interruptions needed to lead the dive and to provide assistance to individual divers.
• Do not engage in any other activities, such as taking photographs or video, while supervising participants.