What happens in the event of cancellation or delay of delivery due to force majeure (e.g. adverse weather)?

If, by reason of force majeure, the Owner fails to deliver the Yacht to the Charterer at the Departure Port at the commencement of the Charter Period and delivery is made within forty-eight (48) hours of the scheduled commencement date, or within one tenth (1/10th) of the Charter Period, whichever period is the shorter, the Owner shall pay to the Charterer a refund of the Charter Fee at a pro rata daily rate or if it be mutually agreed the Owner shall allow a pro rata extension of the Charter Period.