46 CFR § 197.436 - Liveboating.
(1) Diving is not conducted in seas that impede station-keeping ability of the vessel;
(2) Liveboating operations are not conducted -
(i) From 1 hour after sunset to 1 hour before sunrise; or
(ii) During periods of restricted visibility;
(4) A boat is ready to be launched with crew in the event of an emergency.
(b) As used in paragraph (a)(2)(ii) of this section, restricted visibility means any condition in which vessel navigational visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms or any other similar causes.
(1) Diving is not conducted at depths greater than 220 fsw;
(2) Diving is not conducted in seas that impede diver mobility or work function;
(4) Each diver carries a reserve breathing gas supply;
(6) Diving is not conducted with in-water decompression times greater than 120 minutes; and