There are two basic motions for a boat - pitch is a forward-and-back tilting, while yaw is a side-to-side tilting. A ship that does both is in dire straits.

Each watch on a ship consists of four hours, which are divided into eight half-hours. In order to keep track of time on the watch, a different number of bells are rung each half-hour - one bell after 30 minutes, two bells after an hour, and so on. For the shift starting at midnight, seven bells are rung at 3:30. For the four o'clock shift, seven bells ring at 7:30, and for the eight o'clock shift, seven bells ring at 11:30. While the seven bells could refer to either the time Bobby's death was discovered or the time it happened, this seems unlikely, as reports have him going to bed at approximately 4am and him being discovered around 11am.

A more likely explanation is rooted in the naval expression, "to knock seven bells out of a man", or to nearly kill him. Presumably, to knock eight bells out of him would mean death.

Another possible reference is the sinking of the Titanic, which struck an iceberg in the northern Atlantic just after 11:30 the night of April 14th.

"All hands on deck" was the frequent order when all members of a ship's crew were needed to be prepared for action. So if all hands were left on deck, it implies that they were either deserted or not needed.

The sirens were a race of sea nymphs in Greek mythology whose calls were irresistible to anyone who came near them. They lived near an island that was surrounded by hazardous rocks, and sailors who came too close were invariably lured in by their songs and sent to their doom by shipwrecking on the rocks.