Which of the following is recommended maintenance for an inboard boat?

Replacing deteriorated engine and hull zincs if corroded is essential for maintaining an inboard boat because these zincs are part of a cathodic protection system that helps prevent corrosion of metal parts submerged in water. Over time, zinc anodes corrode away to protect more crucial components such as the engine and hull fittings. If these anodes are not replaced regularly, the underlying metal can start to corrode, leading to significant structural damage or costly repairs.

Regularly replacing zincs helps ensure that the boat remains in good condition and maintains its longevity. Corrosion is a common issue for inboard boats, and proactive maintenance regarding zincs is a straightforward way to mitigate this risk. While cleaning the hull after every use and checking GPS systems are also relevant maintenance tasks, they do not directly address the critical issue of preventing corrosion, making the maintenance of zincs particularly important.