Action of the Stand-On Vessel applies only where a risk of collision exists between two (not three or more) vessels. In such a situation, the boat required to keep out of the way is the "give-way vessel" (Rule 16). Rule 17 covers the other vessel, the stand-on vessel."
You can break the actions required by the stand-on vessel can be broken down into four steps:
- Before risk of collision exists, either vessel is free to maneuver at will.
- Once risk of collision exists, except to avoid hazards, the stand-on vessel must maintain its course and speed.
- If it becomes apparent to the stand-on vessel that the give-way vessel is not taking the appropriate (early and substantial) action to keep out of the way, then the stand-on vessel MAY take action to avoid collision. If both boats are power driven, however, the action must not turn to port for a give-way vessel on her port side. Any maneuvers she makes must be accompanied by the appropriate maneuvering signal. If she chooses not to maneuver, then she should sound the danger signal (five short blasts on the whistle). If the give-way vessel can be readily identified by either name, characteristics, or location, then a call on VHF CH13 or 16 would also be appropriate.
- If the situation should deteriorates to the point where a collision can no longer be avoided by the action of the give-way vessel alone, the stand-on vessel MUST to take the best action it can to avoid collision.