Default options don't work properly?

[tjk]

Given the following example.docopt:

Naval Fate.

Usage:
  naval_fate.py ship create <name>...
  naval_fate.py ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.py ship shoot <x> <y>
  naval_fate.py mine (set|remove) <x> <y> [--moored|--drifting]
  naval_fate.py --help
  naval_fate.py --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

I'd expect --speed to equal 10 if no options are passed, however I see this instead:

$ ./example.out
Commands
    mine == false
    move == false
    create == false
    remove == false
    set == false
    ship == false
    shoot == false
Arguments
    x == (null)
    y == (null)
Flags
    --drifting == false
    --help == false
    --moored == false
    --version == false
Options
    --speed == (null)