Abstract: A casing tensioning system applies tension to a string of casing between a subsea wellhead and a surface wellhead. The tensioning system has an outer hanger with a load ring and a ratchet ring that engage a mandrel. The mandrel is connected into the string of casing. The outer hanger has a disengaged position and an engaged position. When running, the outer hanger lands on a load shoulder in the surface wellhead while the casing hanger is in the disengaged position. The operator subsequently lowers the casing and latches the casing to the subsea wellhead. The operator then removes the casing running tool. The operator sets an annulus seal using a seal running tool. The annulus seal actuates a release member to cause the ratchet ring to move to the collapsed engaged position. After the seal is set the operator pulls tension on the casing.