Companies may submit a request online on the website of the Ministry of Transport and Communications (MOTC) to obtain the minimum safe manning certificate of the big vessels. It is a certificate issued for Qatari vessels based on its type, size, and area of navigation. The company has to offer a suggestion for the number of persons that the vessel is certified to carry.
Planning and Maritime Transport Licenses Department at MOTC (Check Google Maps).
You may check the service information page on MOTC website.