29 CFR §1910.427

1. (a)General. Employers engaged in diving operations involving liveboating shall comply with the following requirements.
2. (b)Limits. Diving operations involving liveboating shall not be conducted:
   1. (1)With an inwater decompression time of greater than 120 minutes;
   2. (2)Using surface-supplied air at depths deeper than 190 fsw, except that dives with bottom times of 30 minutes or less may be conducted to depths of 220 fsw;
   3. (3)Using mixed gas at depths greater than 220 fsw;
   4. (4)In rough seas which significantly inpede diver mobility or work function; or
   5. (5)In other than daylight hours.
3. (c)Procedures.
   1. (1)The propeller of the vessel shall be stopped before the diver enters or exits the water.
   2. (2)A device shall be used which minimizes the possibility of entanglement of the diver's hose in the propeller of the vessel.
   3. (3)Two-way voice communication between the designated person-in-charge and the person controlling the vessel shall be available while the diver is in the water.
   4. (4)A standby diver shall be available while a diver is in the water.
   5. (5)A diver-carried reserve breathing gas supply shall be carried by each diver engaged in liveboating operations.