46 CFR §11.459

1. (a)An applicant for an endorsement as Master of river self-propelled vessels of unlimited tonnage must meet the same service requirements as Master of inland self-propelled vessels of unlimited tonnage.
2. (b)An applicant for an endorsement as Master or Mate of river self-propelled vessels, with a limitation of 25 to 1,600 GRT, must meet the same service requirements as those required by this subpart for the corresponding tonnage Great Lakes and inland self-propelled endorsement. Service on the Great Lakes is not, however, required.