Seal ring, shaft seal assembly, ship propeller and ship

A seal ring, comprising:

• an outer ring body;
• and
• an inner ring body, wherein the inner ring body is located inside the outer ring body, and the inner ring body is connected to the outer ring body;
• and an annular cavity is provided between the inner ring body and the outer ring body, a threaded spiral rib is provided on an inner ring surface of the inner ring body, and the threaded spiral rib extends along a length direction of a central groove of the inner ring body and a circumferential direction of the central groove;
• wherein the seal ring comprises a first end and an opposite second end, the annular cavity comprises an opening defined between an inner wall of the outer ring body and an outer wall of the inner ring body, and facing towards the first end of the seal ring, and a bottom opposite to the opening, at least part of the annular cavity, from the opening to the bottom, is empty;
• and
• wherein the seal ring further comprises a tightening member, the tightening member is located in the annular cavity, and the tightening member is sleeved on the inner ring body.