46 C.F.R. § 45.173
Eligible barges
Only barges meeting the following requirements are eligible for the special load line regime under this subpart:
(a) Unmanned, river service, dry-cargo barges;
(b) Barges that have been designed and built to at least the minimum scantlings of the American Bureau of Shipping River Rules which were in effect at the time of construction;
(c) Barges with a length-to-depth ratio less than 22;
(d) Barges on the Milwaukee route must not be more than 10 years old; and
(e) All weathertight and watertight closures (dogs, gaskets, covers, etc.) must be in proper working condition.