Hey Chief,
Scuba PT was all day long, mostly push-ups and flutter kicks with twin 80's and gear, pool skills (weighted belt swim, ditch-n-dawn,etc). However, it was the cohesion that develops, even interservice rivalry goes out the window. During Ranger school I cut my leg on some wire the last week before graduation, although I had already finished my patrols for the course you still have a load to carry for the rest of the squad. My Ranger buddy ( a Scout with the 101st) said; " I'll carry you on my back if I have to, but you're finishing.", he TOOK a portion of my already bulging ruck and helped me through the course. I have always looked to return the favor everywhere I go. Chuck had a lot to lose by helping me, him not getting a Ranger tab would have affected his Army carreer. As a Marine all I got was a license plate, a T-shirt, and the satisfaction.
Anyway, I like Jowett's "Unrevealed secrets of Man", Kettlebells, Clubbells, and Matt Fureys' "Royal Court". Surely you read also about the Captains of Crush. My endurance and leg strength from Hindu Squats was easily documented ( from 25 to 125 squats in two months time). That is what I truly consider to be the bare minimum fitness level for a person who EXPECTS a confrontation.
Yours in manly excellence,
Enrique