For ease of reference for others:
(d) Service on Articulated Tug Barges (ATBs) and Integrated Tug Barges (ITBs). Service on ATB or Dual Mode ITB units is creditable for an original deck officer endorsement or raise of grade of any deck officer endorsement. Service on an ATB or Dual Mode ITB with an aggregate tonnage of 1,600 GRT/3,000 GT or more is creditable on a two-for-one basis (2 days experience equals 1 day of creditable service) for up to 50 percent of the total service on vessels of 1,600 GRT/3,000 GT or more required for an unlimited officer endorsement. The remaining required service on vessels of more than 1,600 GRT/3,000 GT must be obtained on conventional vessels or Push Mode ITBs.