Having played the two player game multiple times, I was pretty meh on Shipyards. In a two player game the cost of 7 to get a -5 discount on only 3 total cards later on is pretty weak.

But as a warning to those going from two player to games with more players: Shipyards becomes its most powerful with 3 players if you can pick it up cheap --because there's more multiples of the cards that it discounts, and you'll have a monopoly on the discount.

3 players: 1 Shipyard card, 5 cards that can be discounted.
4 players: 2 Shipyard card, 6 cards that can be discounted.
5 players: 2 Shipyard card, 8 cards that can be discounted.