in my lifeguard class i have too sink with feet first to pick up a brick but i only end up flat down.
jump in with as much downward force as possible. make your body streamlined and aimed at the bottom. let as much air out of your lungs as possible to reduce buoyancy. when all else fails ask your instructor for better instruction that is there job after all.
there r some tecnique to swim..............for bigginers its vry tought to swim in 10 feet pool...............
Pin dive in from the side?