The Seafarer Act Article 36

It may be set down in the employment contract that the seafarers’ overtime charges shall be computed based on the normal wage per hour and paid as a fixed overtime charge. Nevertheless, the hours for overtime computation charge shall be at least 85 working hours per month.
中文原文 船員法第36條
僱傭契約得約定船員之加班費數額按照船員之平日每小時薪資標準計算,列為固定加班費發給船員。
但計算時數,每月至少應等於八十五工作小時。

English translation for reference only; the Chinese text prevails. Not legal advice.