Not terrain, exactly, but some thought as to the fates of those who are unfortunate enough to go overboard during battle - whether it is sharks, the lucky discovery of a bit of floating debris, the horrible fate of returning as one of the wandering dead - to stalk the deck of the ship that once they served, or the ironic death of falling overboard, survive the battle, only to be crushed by the ship's hull as she comes around against the wind.
Superstitions - a Jonah on board ship, possibly even a PC; the killing of an albatross; St. Elmo's Fire the night before a battle; a woman aboard ship, or worse - whistling; the pilot fish abandoning the ship before sight of land; the sweet murmurs and drowning glances of the treacherous mer-maid; sea phosphor, who knows what that portends?...
Or worse, a death-hulk, all a-sail, her crew all dead, or vanished now, o'er takes the ship, anon.
The western wave was all a-flame,
The day was well nigh done!
Almost upon the western wave
Rested the broad bright sun;
When that strange shape drove suddenly
Betwixt us and the sun.
And straight the sun was flecked with bars,
(Heaven's Mother send us grace!)
As if through a dungeon-grate he peered
With broad and burning face.
Alas! (thought I, and my heart beat loud)
How fast she nears and nears!
Are those her sails that glance in the sun,
Like restless gossameres?
Are those her ribs through which the sun
Did peer, as through a grate?
And is that Woman all her crew?
Is that a Death? and are there two?
Is Death that Woman's mate?
Her lips were red, her looks were free,
Her locks were yellow as gold:
Her skin was as white as leprosy,
The Nightmare Life-in-Death was she,
Who thicks man's blood with cold.
The naked hulk alongside came,
And the twain were casting dice;
`The game is done! I've won! I've won!'
Quoth she, and whistles thrice....
The Auld Grump