Players take it in turns to run convoys of ships in partnerships. Two players are chosen by spinning the compass card to create a convoy. They become players 'North' and 'South'. All other players act individually to try and stop them.
A convoy is a running sequence of 4 'Merchantmen' cards and the 'Home' card. The merchantmen are numbered from 1-6 so there are 3 ways of making a convoy. The convoy has to be in North's hands to score, so North and South work together to realign their cards. When they have a convoy North calls 'Convoy' and the round ends.
Any other player (not North) can halt a round by declaring their hand when they have collected certain configurations. Other cards
include 'torpedoes', 'mines', 'cruisers', 'destroyers' and 'submarines'.
After adding up the points the winner is the first to 1000 points.