When a sailboat overtakes a powerboat which is the stand on?

When a sailboat is the overtaking vessel, she must keep clear of the powerboat. Any vessel overtaking another must stay clear of the vessel being overtaken (Rule 13).

Please refer to the Navigational rules. Specifically Rules 8, 9, 12, 13, 14, 15, 16, 17 & 18. A link is provided below.