If you have completed minimum class Xth then you can apply for CDC after completing the above-mentioned basic STCW courses. Then you can apply for CDC. For this, you do not need to undergo any pre-sea training from institutes. You will be able to join the ship as a utility hand using that CDC. The term Open CDC is used as a layman's term. Open CDC is applied by many Indians who are working onshore as welders, fitters, turners, etc who wish to join the ship. Mostly they join the ship as a riding squad at first in order to gain sailing experience with which they can complete their other certifications and can serve on the ship with a specific rank. Note: Make sure you apply CDC through a DG shipping-approved Institute.