What statement is true concerning the forward and after bulkheads of a shaft tunnel?

Correct Answer: Option D — The shaft tunnel aft bulkhead is the aft peak bulkhead, the shaft tunnel forward bulkhead is the machinery space aft bulkhead, and both bulkheads are watertight.

The shaft tunnel is a critical watertight enclosure. Its forward bulkhead is the machinery space aft bulkhead, and its aft bulkhead is the aft peak bulkhead. Both must be watertight to maintain the integrity of the vessel's subdivision and prevent progressive flooding into the machinery space.