The correct answer is C) Using the special wrench provided. To manually lockout an SSS (Selectable Shaft Speed) clutch, the proper procedure is to use the special wrench provided by the manufacturer. This wrench is designed to engage the clutch locking mechanism, allowing the operator to physically lock the clutch in place. This is the recommended method specified by Coast Guard regulations and the clutch manufacturer, as it ensures the clutch is properly secured without damaging the internal components. The other answer choices are incorrect because: A) Removing the locking pawls would disable the clutch's safety features, which is not an approved procedure. B) Calculating the engagement speed does not physically lock the clutch. D) Using air pressure is not the proper method for manually locking out an SSS clutch.