(a) To qualify for a national ocean or near-coastal endorsement for service on vessels of unlimited tonnage—

(1) All the required experience must be obtained on vessels of 100 GRT or more; and

(2) At least one-half of the required experience must be obtained on vessels of 1,600 GRT or more.

(b) If an applicant for a national endorsement as master or mate of unlimited tonnage does not have the service on vessels of 1,600 GRT or more as required by paragraph (a)(2) of this section, a tonnage limitation will be placed on the MMC based on the applicant's qualifying experience. The endorsement will be limited to the maximum tonnage on which at least 25 percent of the required experience was obtained, or 150 percent of the maximum tonnage on which at least 50 percent of the service was obtained, whichever is higher. However, the minimum tonnage limitation calculated according to this paragraph will be 2,000 GRT. Limitations are in multiples of 1,000 GRT using the next higher figure when an intermediate tonnage is calculated. When the calculated limitation equals or exceeds 10,000 GRT, the applicant is issued an unlimited tonnage endorsement.

(c) Tonnage limitations imposed under paragraph (b) of this section may be raised or removed in one of the following manners:

(1) When the applicant provides evidence of 6 months of service on vessels of 1,600 GRT or more in the highest grade endorsed, all tonnage limitations will be removed.

(2) When the applicant provides evidence of 6 months of service on vessels of 1,600 GRT or more in any capacity as an officer other than the highest grade for which he or she is endorsed, all tonnage limitations for the grade in which the service is performed will be removed and the next higher grade endorsement will be raised to the tonnage of the vessel on which the majority of the service was performed. The total cumulative service before and after issuance of the limited license or MMC officer endorsement may be considered in removing all tonnage limitations.

(3) When the applicant has 12 months of service as able seaman on vessels of 1,600 GRT or more while holding a license or endorsement as third mate, all tonnage limitations on the third mate's license or MMC officer endorsement will be removed.

(d) No applicant holding any national endorsement as master or mate of vessels of less than 1,600 GRT, less than 500 GRT, or less than 25-200 GRT may use the provisions of paragraph (c) of this section to increase the tonnages of his or her license or endorsement.