private bool isCloseToOther(Placement ship)
        {
            for (int i = 0; i < ship_list.Count; i++)
            {
                if (ship_list[i] != ship)
                {
                    for (int j = 0; j < ship.Vessel.Length; j++)
                    {
                        if (isShipHere(new Coordinate(ship.X, ship.Y - 1)) || isShipHere(new Coordinate(ship.X, ship.Y + 1)) || isShipHere(new Coordinate(ship.X + 1, ship.Y)) || isShipHere(new Coordinate(ship.X - 1, ship.Y)))
                        {
                            return true;
                        }
                    }
                }
            }
            return false;
        }
        private bool isShipHere(Coordinate cor)
        {
            if (cor.X < 1 || cor.Y < 1) { return false; }
            for (int i = 0; i < ship_list.Count; i++)
            {
                for (int j = 0; j < ship_list[i].Vessel.Length; j++)
                {
                    if (ship_list[i].Orientation == Orientation.Horizontal)
                    {
                        return (ship_list[i].Y == cor.Y) && (ship_list[i].X <= cor.X) && (ship_list[i].X + ship_list[i].Vessel.Length > cor.X);
                    }
                    else
                    {
                        return (ship_list[i].X == cor.X) && (ship_list[i].Y <= cor.Y) && (ship_list[i].Y + ship_list[i].Vessel.Length > cor.Y);
                    }
                }
            }
            return false;
        }