Pressure vessel and manufacturing method thereof

A pressure vessel, comprising:

• a vessel body that comprises a cylindrical-shaped straight body portion with a spiral-shaped projection portion at an outer peripheral surface of the straight body portion;
• and
• a covering portion that comprises a fiber bundle wrapped onto the outer peripheral surface of the straight body portion, wherein
• the fiber bundle comprises:
• a first layer wrapped onto the outer peripheral surface of the straight body portion in a first spiral pattern running parallel to the projection portion so as to cover the outer peripheral surface of the straight body portion, and
• a second layer above the first layer, the second layer wrapped in a second spiral pattern along a direction that intersects with the projection portion, and
• a height of the projection portion is less than a thickness of the first layer of the fiber bundle.