Rules of Engagement
Before attacking a ship in the Open World, note that even large fleets are represented by a single ship in the Open World. Therefore it is advisable to check a target's information carefully.
Left-click on the intended target, it is then highlighted by a small circle drawn on the water around it. An information window is shown in the upper right corner of the display. The info window will indicate the nationality and type of ship, plus any other ships accompanying it as a supporting fleet. If it's a player controlled ship (or fleet), the player's rank and name (and clan name) will be shown. Also displayed is the Battle Rating (BR) for the target to compare to your own and assist in estimating your chances of success.
Options are also shown for sending a Private Message or Invite to Group, and a red Attack button that will be inactive (dull) when you are out of attack range.
Ordinarily you may not attack trader ships of your own nationality or of your allies without being declared a pirate and banished. But any ship that is flagged as carrying contraband goods are considered illegal smugglers and may be attacked without penalty.
When the Attack button is active (bright), you may left-click it to 'tag' your prey and begin a 30 second attack countdown. Once tagged, the red crossed swords battle marker appears above the target ship and two more circles are drawn around your ship. An "attack" circle whose radius marks the distance where the Attack button went active, and a much larger Pull circle.
This is the radius around the attacking ship that the target ship must be kept within for the attempted attack to succeed. To abort an attack, steer away from the target ship until it is outside the attack circle when the counter reaches zero. To escape if you have been tagged, try to flee on a heading towards a point on the perimeter with favorable wind conditions.
Very large diameter circle around the attacking ship with a radius equal to a 2 minute downwind sail. Note: All player and NPC ships within the 'pull' circle will be brought into the battle instance where the actual ship to ship combat will take place. Be aware that fellow nationals or allies may be very annoyed to be pulled into a battle instance without warning.
Battle Instance Launch
When the tag timer expires and the battle starts, all ships from the "pull" circle will spawn into a separate battle instance. They will all keep their relative positions and headings under the same wind conditions as they existed in the Open World. It is therefore important to maneuver for best possible advantage before the tag timer reaches zero.
Open Battle Instances
Ordinarily once the battle starts the Open World battle marker remains but is closed so no other ships may enter. The exception to this is an officer perk called 'signalling', which will hold the battle instance open for other players to join for 5 minutes.∇
Ships attempting to join an open battle instance are subject to a 25% battle rating ratio restriction. If a ship (and accompanying fleet ships) would cause the battle rating for their side to be over 25% higher than the opposing side's, it will not be able to join the battle.