15.520—Mobile offshore drilling units.

(a) The requirements in this section for mobile offshore drilling units (MODUs) supplement other requirements in this part.
(b) The OCMI determines the minimum number of officers and crew (including lifeboatmen) required for the safe operation of inspected MODUs. In addition to other factors listed in this part, the specialized nature of the MODU is considered in determining the specific manning levels.
(c) A license or officer endorsement on an MMC as offshore installation manager (OIM), barge supervisor (BS), or ballast control operator (BCO) authorizes service only on MODUs. A license or endorsement as OIM is restricted to the MODU type and mode of operation specified on the credential.
(d) A self-propelled MODU other than a drillship must be under the command of an individual who holds a license as master endorsed as OIM or an MMC with master and OIM officer endorsements.
(e) A drillship must be under the command of an individual who holds a license or MMC officer endorsement as master. When a drillship is on location, the individual in command must hold a license as master endorsed as OIM or an MMC with master and OIM officer endorsements.
(f) A non-self-propelled MODU must be under the command of an individual who holds a license or MMC officer or endorsement as OIM.
(g) An individual serving as mate on a self-propelled surface unit other than a drillship must hold an appropriate license or MMC officer endorsement as mate and an endorsement as BS or BCO. An individual holding a license or MMC officer endorsement as barge supervisor or ballast control operator may be substituted for a required mate when a self-propelled surface unit other than a drillship is on location or under tow, under certain circumstances as determined by the cognizant OCMI.
(h) An individual holding a license or MMC officer endorsement as barge supervisor is required on a non-self-propelled surface unit other than a drillship.
(i) An individual holding a license or MMC officer endorsement as barge supervisor may serve as ballast control operator.
(j) The OCMI issuing the MODU's certificate of inspection may authorize the substitution of chief or assistant engineer (MODU) for chief or assistant engineer, respectively, on self-propelled or propulsion assisted surface units, except drillships. The OCMI may also authorize the substitution of assistant engineer (MODU) for assistant engineer on drillships.
(k) Requirements in this part concerning radar observers do not apply to non-self-propelled MODUs.
(l) A surface mobile offshore drilling unit underway or on location, when afloat and equipped with a ballast control room, must have that ballast control room manned by an individual holding a license or MMC officer endorsement authorizing service as ballast control operator.
[CGD 81-059a, 55 FR 14805, Apr. 18, 1990, as amended by USCG-2006-24371, 74 FR 11260, Mar. 16, 2009]