The U.S. Navy has issued a Certificate of Alternate Compliance for the USS SAVANNAH (LCS 28) because its special design prevents it from fully adhering to certain navigation light requirements of the International Regulations for Preventing Collisions at Sea, 1972 (72 COLREGS). Due to these unique design features, complying with the 72 COLREGS would interfere with the ship’s functions as a naval vessel. This notice serves to inform mariners that the USS SAVANNAH will not meet the standard requirements for navigation lights in areas where these rules apply. The certificate took effect on February 8, 2021.
Simple Explanation
The USS SAVANNAH is a special Navy ship that has some unique features, so it can't use regular boat lights exactly like other ships do. This is a way to let people know that when they see this ship, its lights might look a bit different, but that's okay because it's made to do special things.