Are you asking about drift diving or a rip current? Your question is somewhat confusing. In drift diving everyone in the group enters the water at the same time and descends. You fly with the currents until time to turn the dive. Deploy your SMB from a reel and ascend to your safety stop. Wait there for your required time and then surface. Meanwhile the boat has been following the groups bubbles and will be close by to pick up the group. Drift diving is very enjoyable. Now rip currents, that's a whole new ballgame.