[Norfleet]

The castle is an excellent choice for a fort: It has a modest cost of only $450, only 50% more than the watchtower, which gives it a modest build time of 3 turns. It has an excellent admin of 40: Only the Fortified City does better, and the Fortified City costs $750 and 5 turns! Unless the map is exceptionally small and/or you have no plans to build many other fortresses, or you absolutely, positively, must have the metric assload of supply that the Fortified City grants, the castle is a very good choice. Pointwise, the cost is the same: 80 points. You certainly can't go wrong with that. The only drawback of the castle is that its defense value is not a great asset, but nor is it absolutely wretched. Besides, who plans a strategy around being sieged? Any castle will buy you a minimum of one turn, and no castle will hold out for any real length of time against real opposition. A higher defense will just make it more bothersome for YOU to take it back!