public bool DeleteBoat(Boat a_boat)
        {
            bool success = this.Boats.Remove(a_boat);

            if (success)
            {
                //un-subscribe to boat events
                a_boat.RemoveSubscriber(this);

                this.NotifySubscribersChangeMade();
            }

            return success;
        }
        //Methods
        public bool AddBoat(Boat a_boat)
        {
            if (a_boat.HasCorrectDetails)
            {
                //subscribe to boat events
                a_boat.AddSubscriber(this);

                //add it to array
                m_boats.Add(a_boat);

                //notify subscribers
                this.NotifySubscribersChangeMade();

                return true;
            }

            return false;
        }