I am working towards a captains license here in Canada. The process here is you require a Candidate Document Number ( CDN ) and a book issued by Transport Canada to record sea time in. I am working as a deck hand with a dive operator to build my time, and get experience handling the boat. In the spring I hope to be taking the MED, Marine Emergency Duties, course which is required, plus the medical. After that it is a matter of the operator I am working for thinking my skills and experience are such I am a safe captain and can take the transport Canada test.
On colour blindness, which I have, I have not done the marine medical yet, however I do hold my private pilots license and required a medical for that. I cannot pass the test they give you with the various dots and you should see shapes based on your colour issues, ( can't remember name of this test.) Based on that it is determined I am not fully colour blind but have a colour deficiency and I am unable to achieve a commercial rating for flying. I am however still able to achieve my private medical, and have a night rating as I can pass other tests such as the Farnsworth. In talking with the Transport Canada medical examiner they indicated that I should not have an issue passing the marine medical if I have passed a medical for aviation, as the marine medical is not as stringent. I also had to pass a medical, including colour test, for my job and had no issue there either. Just don't ask me to help choose between the 47 different "blues" in the house paint section.