To port, or starboard, back, or stop her!

“But when upon your port is seen

A steamer’s starboard light of green,

There’s not so much for you to do,

For green to port keeps clear of you.”

4. All ships must keep a good look-out, and steam-ships must stop, and go astern, if necessary.

“Both in safety and in doubt

Always keep a good look-out;

In danger, with no room to turn,

Ease her—stop her—go astern!”