Vide letter of even date,i.e.4th January,1999,the appellant suggested to the respondent that in the absence of a formal charter party with effect from 1st September,1998,a provisional arrangement for a period of four months effective from 1st September,1998 with an option for extension of one month may be mutually agreed to by payment at the rate of 80% on charter hire prevailing on 30th June,1998,as ad hoc hire