Officiel http://www.matagot.com/fr/catalog/extensions/captain-sonar-upgrade-1/808/16
Français - Avec cette extension, la traque sous-marine continue sur 5 nouvelles cartes avec leurs scénarios exclusifs !
Ludovox http://ludovox.fr/jeu-de-societe/captain-sonar-upgrade-one/
Français - 1ere extension pour Captain Sonar
Boardgamegeek https://boardgamegeek.com/boardgameexpansion/218178/captain-sonar-upgrade-one
Anglais - In Captain Sonar, up to eight players take on roles manning a submarine in a fierce battle against rival players. Captain Sonar: Upgrade One adds new elements to the base game, including five new scenarios, two new weapons, eight erasable markers, and different ways to play the Captain and Radio Operator roles.
