Was lean and mean several years back, did a bunch a diving in the early days (70's) and continued off and on for almost 30 years. Some of the divers back then, which included my dive instructor, used no BC's at all, maybe a Mae West, they swam constanty, when we took our OW we did the pool lap thing, around 300 meters no gear, then we tried the hold your breath for a lenght of the pool thing, we also did a 100 meter demonstrating the different swimming strokes we knew, all of this was just to get a good base line of fit and finish, those who needed it, swam everyday before and after classes, then we hit the ocean and swam around in equipment forever, or least it seemed that way. No one in my class was a weak swimmer not even close, don't know if it was any kind of PADI requirement, but it was the requirement imposed by or instructor. NOW, I'm an older FAT GUY, who has been away from diving for several years and let myself get out of shape, however I remember the old days and the swimming that was involved and before I even put back on any scuba gear I hit the pool working myself to 1000 meters twice a week with mask, fins and snorkel, not a leisurely swim either, as fast and as hard as I can push. It's not that scuba diving requires one to be an olympic swimmer on the contrary most of my dives have involved very little hard nose swimming, key word here is most, but just a few (you really only need one) have been, shall I say a bit south of difficult, you truly never know what lies beneath. I won't knowingly dive with a weak swimmer, but I will come to thier rescue if possible. I still perfer to do the rescuing vice being rescued, I'm kinda funny that way. Dive well and Dive often, life is short!:14: