What Kev mentions on the Hang Pulls and Hang Cleans has merit from a power component, but if you're not used to dynamic movements of free weights/barbells, then these may be too advanced without some coaching. I'm speaking about the proper set of the lower lumbar, bootimus maximus, and upper back curvature. You don't want to be wrenching your back or causing blown discs. This is why my thoughts were more toward the slow movements. It's rare that you need to "jerk" tanks off the ground.
Again... your mileage may vary... and I'm not a professional... but Penny and I train Olympic weightlifting (Clean & Jerk, Snatch) twice a week under the watchful eye of a USAW certified coach that has won the State of Ohio team meets a few times. That doesn't mean my advice is worth a tinker's dam, but we hear his coaching points regarding our back posture and development all the time. (...and we've still got a long way to go...)
I would defer to someone like Coach Izzy here on the board that is also a USAW weightlifting coach with athletes at the National and International level.
I apologize for turning this into an essay... but you only have one back... and the recovery time takes away from the diving or other fun activities you might be involved with. Exercise should enhance your physicality and quality of life, not take away from it... lol... Somewhere in the middle of everyone's advice is a path that's right for you... you'll figure it out.