Ocian freight

Yes.

On ocean freight, there is a liability under RCM at the rate of 5%. This is payable when service provider (shipping line) is in non-taxable territory. 

Tax is payable even if this shipping line is billing the foreign exporter. If we know the value, then GST is payable on that value. Otherwise, GST payable on 10% of CIF value. 

Refer Noti 10/2017-IGST + 8 /2017

Thanks

But it is double tax

provisions implied that in a case where a foreign service provider providing
transportation services for export of goods to an Indian customer, the place of supply would be the
destination of goods. This denotes that the underlying transaction was not subject to GST. On the other
hand, identical services rendered by an Indian shipping line or airline were taxable as the place of
supply is the location of the customer in India.