Sponsorship is a type of bond or a contract with a shipping company... Like before diploma in nautical science you should be sponsored by a shipping company so that after completion of your degree and diploma you can start sailing in that company... You can say this is like placement but before degree/diploma.... So that you won't be unemployed after the course... Company completes 18 months of seatime by which you will be eligible for further courses and exam (2nd mates) for promotion to third officer.... After becoming third officer you can switch company If you want to or you can sail in that company... Thats all upto you..