--- a/ship_cmd.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/ship_cmd.c	Sun Dec 03 15:48:21 2006 +0000
@@ -814,7 +814,7 @@
 	UnitID unit_num;
 	Engine *e;
 
-	if (!IsEngineBuildable(p1, VEH_Ship)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
+	if (!IsEngineBuildable(p1, VEH_Ship, _current_player)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
 
 	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);