46 CFR § 12.503 - Service or training requirements.
(b) Approved training programs may be substituted for the required periods of service as follows:
(1) A graduate of a school ship may qualify for a rating endorsement as QMED, without further service, upon satisfactory completion of the program of instruction. For this purpose, school ship is interpreted to mean an institution that offers a complete approved program of instruction, including a period of at-sea training, in the skills appropriate to the rating of QMED.
(2) Training programs, other than those classified as a school ship, may be substituted for up to one-half of the required service. The service/training ratio for each program is determined by the Coast Guard.