In Viking Raids each player takes on the role of a Viking leader, based at a particular port in Scandinavia- Hedeby, or Kaupang, for example. The map of Europe is seeded with counters which may either be treasure or an enemy army. The aim is to get 3 treasures back to your home base, using your longships and warbands. As well as fighting the enemy armies you can fight each other.
In Silver Fleet one player is the Spanish trying to get his Galleons home and the other is the Dutch trying to capture them. Coastal Squadrons protect the Galleons around Cuba, but sooner or later they will have to brave the open sea.
In Frigate, one player commands 2 English ships and the other 2 French ships, clashing off the coast of France. The poor quality fo the French is compensated for by the French shore batteries. The combat simulation is quite detailed with counters for crew and guns.
In Battle for the "Med" one player is the Allies and the other the Axis, fighting for the Mediteranean in 1942. The game uses a standard deck of playing cards to award points for completing various objectives- destroying enemy ships and planes (but they come back via a repairs track) and getting your convoy to Malta (Allies) or Benghazi (Axis). The game ends with turn 10 so you have limited time to acheive your goals.