Crewing ships with well-qualified, trained, and experienced seafarers is the cornerstone of smooth and efficient shipping operations, and crew management companies exist for this reason.
These companies, or crewing managers, are contacted by shipowners, ship operators, or charterers to manage the crew on their ships under a crew management contract. These activities are majorly concentrated in a few locations, such as Cyprus, Malta, Hong Kong, India, the Philippines and Singapore.
Crew management...
https://www.marineinsight.com/maritime-law/ship-crewing-services-and-crew-management/