When securing a jacket-water heated submerged tube evaporator for an extended period of time, you should __________.

Correct Answer: Option C — completely drain the unit

Draining the unit completely is essential to prevent stagnant water from causing localized corrosion or biological growth during extended idle periods. Per standard marine maintenance practices, removing all moisture protects the internal tube bundles and shell integrity from the corrosive effects of trapped, stagnant saltwater or condensate.