The Coast Guard Office of Commercial Vessel Compliance issued Policy Letter 19-01 Change 1 “Enforcement Guidance for Harbor Assist Towing Vessels When Operating Beyond the Boundary Line” and Policy Letter 21-03 “Guidance Concerning the Use of Doubler Plates for Repairs Involving Towing Vessels Subject to 46 CFR Subchapter M”.
Source: USCG
Link: Policy Letters: Update to harbor assist towing beyond the boundary line and use of doublers on Subchapter M towing vessels