Flexible class design that adheres to open-close principle

I'm playing with some application and doing a little refactoring in order to make it more flexible. As I expected, a lot of problems arose. For example i'm trying to find optimal way to delete items from collections in Spaceship class

class Spaceship{
 Weapon Weapons {get;set;}
 Shield Shields {get;set;}

 public void RemoveEquipment(Equipment item){
 switch(item.EquipmentType )
 {
   case EquipmentType.Weapon:
     weapons.Remove(item);
     break;
   case EquipmentType.Shield:
     shields.Remove(item);
     break;
 }    
 }

 public void AddEquipment(Equipment item){
 //works the same way as RemoveEquipment
 }

}

class Equipment{    
 //EquipmentType is enum
 EquipmentType Type {get;set;};
}

class Weapon: Equipment{    
}

class Shield:Equipment{
}

class AutoCannon:Weapon{
}

class LaserGun:Weapon {

}

Is there a better way? What if I want to delete group of items of the same subtype (e.g. every LaserGun in weapons collection - without using reflection) And if I want to add a new type of Equipment, the methods responsible for adding/deleting have to be modified (switch/case).