Bob wrote:

>So, you think there's no issue of UNSAFE practice for a DM to stay
on the boat and tell divers (mostly beginners) to pop up to the
surface every 15 minutes in a 60-minute dive at 25-30 fsw.<<

Yes and yes.

The "beginners" NEVER do 60 minute dives, no matter how shallow. The
"others" generally don't follow the DM's advice to "pop up", or at least
have the sense to do it slowly enough.

For the beginners the slight DCS risk is preferable to being swept off to 
Bermuda (there IS current in the Keys, although much less than up here in
Delray, and divers frequently end up either on other boats or way out at
sea). A DM in the water would most likely further reduce the risk for these
poorly qualified divers. But that's a training issue. They all carry cards
that say they are qualified. And I don't do dive training threads.

Bob, we both know what we (you and me) think about DMs in the water, and so
do the listies that have followed these exchanges over the years. 

I will always tend to avoid boats that do "DM-lead-group-dives", while you
seem to like dives with a DM (in certain locations at least.) 

I prefer to bring my own dive partners, since I know evreything about 
their gear and qualification, while I usually know nothing about the DM on 
a dive boat. We will never agree on this subject. But I don't mind
discussing it from time to time.

Michael