New Jason clause is included in the most of the bill of ladings. The purpose of this clause is to highlight the fact that no matter what, the general average would apply to the contract of carriage.
As per Rule D of the "York Antwerp rules", irrespective of the party at fault that led to an incident, general average would apply.
But local laws of some countries including US do not allow the general average in case of navigation fault of the ship's staff.
Inclusion of "New Jason Clause" in the bill of lading protects the ship owners by having the general average in these cases too.
The New Jason clause states that
“In the event of accident, danger, damage or disaster before or after the commencement of the voyage resulting from any cause whatsoever, whether due to negligence or not, for which, or for the consequence of which, the carrier is not responsible by statute, contract or otherwise, the goods, shippers, consignees or owners of the goods shall contribute with the carrier in general average to the payment of any sacrifices, losses or expenses of a general average nature that may be made or incurred and shall pay salvage and special charges incurred in respect of the goods.
If a salving ship is owned or operated by the carrier, salvage shall be paid for as fully as if the said salving ship or ships belonged to strangers. Such deposit as the carrier or his agents may deem sufficient to cover the estimated contribution of the goods and any salvage and special charges thereon shall, if required, be made by the goods, shippers, consignees or owners of the goods to the carrier before delivery.”