or in other words, put your tiller to port and turn your boat to the right.
If, on the other hand, a vessel is passing side-to you will see but one light and the following verse tells you that
Green to green, or red to red
Perfect safety—go ahead,
or, in other words, if you see a green light on your green or starboard side or a red or port light on your red or port side, the other boat is parallel to you and your course should be kept.
The greatest danger is in approaching another vessel at right angles, but in this case remember that the boat that has the other on the starboard or right-hand side must keep clear of the other, or, as the verse says:
If to your starboard red appear
’Tis your duty to keep clear,
Act as judgment says is proper,
Port or starboard, back or stop her.