SHIELD
Azure (Dark Blue) six bars wavy Argent, overall a pile Gules fimbriated of the second, bearing a Native American arrowhead, point downwards, per fess Sable and Argent (Silver gray), at base (point) two bars Celeste and Or, in base a stylized Canadian maple leaf of the third, detailed and edged of the seventh.
CREST
On a wreath Argent and Azure (Dark blue), an American bald eagle displayed wings inverted Proper.
MOTTO
A scroll Argent doubled and edged Azure (Dark Blue) inscribed "TO BOLDLY TOW Gules.
SHIELD
The wavy bars refer to the Pacific Ocean, area of operations for the USNS SIOUX. There are six bars to represent USNS SIOUX as the sixth fleet ocean tug in the Powhatan class. The red pile resembles a maritime flag and is colored red to emphasize the motto, TO BOLDLY TOW. The arrowhead refers to the Sioux Indians, groups of Native American tribes and First Nation peoples in North America. Here the arrowhead is painted in the colors of the Military Sealift Command resembling the stacks of USNS vessels. The maple leaf denotes the Canadian Forces Unit Commendation awarded to USNS SIOUX for exceptional support to the HMCS PROTECTEUR on February 27, 2014 when the PROTECTEUR experienced a major engine room fire at sea.
CREST
The American bald eagle is a winged symbol for the Sioux people and is considered to be the messenger of the Creator, symbolizes the love the Creator has for the Indian.
SEAL
The coat of arms as blazoned in full color on a White oval within Dark Blue designation band, edged with a Gold chain border and bearing the name USNS SIOUX at top and T-ATF 171 at base, all Gold.