Abstract
Currently we have built a number of modern vessels serving the Navy. However, many types of equipment installed on the ship still have to be imported, moreover, the process of operating and maintaining equipment systems has many shortcomings that are not suitable with the operating conditions of the Vietnamese island waters. As a result, the operation of ships is ineffective, mobility and safety are not high. Therefore, it is necessary to study appropriate methods and maintenance strategies to bring economic efficiency and reliability to the navy vessels. Within the content of the article, the author builds a method to set up running hours to replace piston rings for HQ888 navy diesel engine when operating in Vietnamese waters.