I'm in the Navy and unfortunately we have a four section duty meaning I have to be on the ship for a full 24 hours every four days. So, basically. Our ship does not have a gym right now for we are on a barge and the ship is in dry dock. Besides the simple push-up, sit-up, and pull-up routine, could you give personal suggestions on other with-out weight workouts that I can do to keep up to par on those unfortunate days?