[Background]

High-speed engines (main/auxiliary engines, power transmission devices) of domestic passenger ships are currently exempt from open inspections for up to 9,000 hours if they are in good maintenance and operating condition (*Every 5 years or 9,000 hours, whichever comes first*). 

Due to advancements in manufacturing technology, the average recommended inspection interval by manufacturers has increased to 13,600 hours over 5 years. Thus, the "9,000 hours" threshold needs to be changed to "the period recommended by the manufacturer." Additionally, while exemptions beyond 5 years were allowed for those with maintenance service contracts, a specific limit is needed to ensure safety.

[Main Points]

The criterion for high-speed engine open inspection is changed from "9,000 hours" to "the period recommended by the manufacturer," with the maximum exemption period capped at 8 years (reflecting that manufacturer recommendations range from 6 to 15.3 years, averaging 8.8 years).