I agree with Alan, a gallon of POR-15 would coat a battleship!
Plus you would have the problems of storing it once opened.

I reckon I've used about 3 1/2 pints in all and painted my chassis,inside my cab (rear panel,roof,floor and firewall)
Plus numerous small parts.

It does go a long way!

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.