Marine diesel mechanics maintain, diagnose, and repair diesel engines that power all types of water-based vessels. Working at a marina or a large shipping firm, you maintain diesel engines on vessels, performing regular maintenance and troubleshooting problems as needed. Other duties and responsibilities include travel to boats in distress to fix engines. As a cruise or cargo ship diesel mechanic, you monitor diesel engines during voyages to ensure smooth operation. You utilize problem-solving skills to minimize disruptions to boat movement and ensure passenger safety. Continuous education is important, as you continually learn about new engine types and maintenance techniques.