I believe the answer is
E1
Forward unto dawn, you will see a bright halo
brightest in the heavens, you'll see fiery day-glo.
I believe represents the compass heading East, for E
Now think of two and a rose, you'll need a part of me,
But only one and not three, I will be your pre
Before two I will go, if you want to stay alive,
I believe this represents represents row one.
The possibility space was narrowed by looking at the pattern, and discovering the 7 locations an additional ship-piece could be:
E1, D2, F2, D5, E6, F7, G8
Or perhaps, treating each part of the riddle as describing a single ship:
A long due south you'll find my face, just short of north,
just half way to my place, a new day will come forth
This could be referencing the Carrier the long, facing south, just shy of the north border. Halfway to the place a new day comes forth being a reference to an east facing ship.
Forward unto dawn, you will see a bright halo
brightest in the heavens, you'll see fiery day-glo.
And this is that east-facing ship, the Destroyer, because that's the only ship that fits.
Two plus one is three, as every school child knows,
Solving me is easy, as far as puzzles go.
This represents one of the three-length ships, probably the F ship. We know it's vertical, but don't know its facing,
Now think of two and a rose, you'll need a part of me,
But only one and not three, I will be your pre
I don't understand this one fully, it looks like it's describing Two Rows, which could mean the Battleship and other 3-ship next to eachother, which matches the picture... but they're arranged in columns, not rows. the one prefixing the not-3 could be the Destroyer in front of the Battleship? Meaning these ships are facing north?
Before two I will go, if you want to stay alive,
Hurry now, solve it quick, or your end is nigh."
I believe this is telling us which of the two possibilities for the Carrier in E is correct, meaning E1. Coincidentally what I originally guessed looking at only parts of the riddle.