Boulder reef as opposed to a rocky reef or coral reef, stony reef or biogenic reef. All perfectly legitimate usages of 'reef' though this particular one seems not to be very scenic diving.... Dunno what the cylindrical jobbies are. Artificial reef is also a Thing.
Was that the boat they were diving off? If it was and they weren't running a tender for pick-up the helm had no business anchoring while divers were in the water. If not, where was their boat cover? Should have been fending off the interloper - these were benign conditions and the divers' bubbles should have been plain though a marker buoy per pair might have been good.
@@AdventuresWithSteven I will ask them to sub, thus far I put a link to your vid and channel in my description, I might have a lot of subs, but don't really get a lot of views as my content is a bit meager. Good Luck with your channel!
Thanks for the comment. There isn't much I could put in because of copyright reasons, and everything I could use isn't appropriate. I will find something better for the next one. Thanks