 While the NATO rank code is OF-3, the official translation of the rank as per NATO STANAG 2116 varies between "commander junior grade" and "commander" (with the next senior rank being translated as "commander senior grade").Some NATO members class their corvette captains as OF-4 when they are serving afloat.The Russian/Soviet equivalent is "captain, 3rd grade" ("капита́н 3-го р́анга").