The U.S. Coast Guard issued guidance regarding the impact of accelerated single hull tanker phase-out dates and voluntary compliance with the Condition Assessment Scheme by U.S. tank vessels. The U.S. has reserved its position regarding MARPOL Regulations 13G and 13H. Some U.S. tank vessels, though, make calls in nations that enforce these regulations. The guidance addresses documentation of voluntary compliance by these U.S. tank vessels with the international requirements. MOC Policy Letter 04-11 (HK Law).