A small passenger vessel, operating only on domestic routes, which is operated in salt water for more than three months in a year must undergo a dry dock and internal structural examination at least once every __________.

Correct Answer: Option A — 2 years

46 CFR 176.600 requires small passenger vessels operating in salt water for more than three months annually to undergo a dry dock and internal structural examination at least every two years. This frequency accounts for the accelerated rate of corrosion and structural degradation inherent in saltwater environments.