Seabear70:
The reason I'm making the guess that I am, is partially because of the low vis. If you've got the money for something like that, go somewhere nicer to dive... It sounds like they're diving on a spot that has nothing much to look at, and nothing much to do
Lo-vis diving in these parts is the rule, not the exception. It sounds to me like they were diving a near-shore rock outcropping called Strawberry Ledge... because even in the lo-vis, you can sometimes see the reddish color from the anemonae and seaweeds that grow on it. It's hardly a spot with nothing to do, but it's a bit too far to swim to as a shore dive. A small boat and an inexpensive hookah system would be a reasonable way for several people to dive it, and would cost less and give longer bottom times in shallow water than getting them each their own gear.
Seabear70:
Then consider, it's a small boat, right? Why have one tender and another on watch? They were likely following some rather strict procedures. That's pretty anal even for DIR'ers.
Sure it's a small boat. If it was a big boat, there'd be better places around here to dive with it. When boat diving, it's a good idea to have one person tending to the boat, right? Well, when diving with a hookah, it's a good idea to have someone tending it too, so that lines don't get fouled, and so that exhaust from the built-in compressor doesn't blow into the air intake. If I were relying on it for breathing, I wouldn't want the guy tending it to split his attention between being my life support and driving. I don't consider that anal... I consider it good sense. Also, it's common for recreational hookahs to have two hoses. With 4 people out, only having the ability to have two breathe underwater at a time is a good argument for having two stay in the boat.
I don't think hookah systems are DIR.
Seabear70:
If I've already come to these conclusions, then it's an easy guess to figure out he exposure protection, Military divers tend to wear wetsuits in my experience, unless there is a specific reason not to.
You mean, like extended bottom times in cold New England water? Lots of folks up here dive dry year-round, and in my experience just about nobody has "markings" you could see from shore, including police dive team members.
Seabear70:
Why a radio? The types of divers I described would be unlikely to go in the water with that gear without one.
True, but the kind of divers who'd be in a small boat off Nantasket beach with one of these would be unlikely to have them:
Hookah rig with compressor
I suppose it COULD be DEA agents or military doing some kind of training or recovery operation, but it would be a strange place for it, and I don't think there's any reason to believe it wasn't just some folks out having a bit of fun in a buddy's boat.