What sort of certifications/official courses are available to learn to sail large boats?

chillaxin asked: I am an experienced dinghy sailor and racer, but i do not have a lot of big boat experience, i was wondering where there are courses to learn about big boats and what sort of official certifications there are that you need to crew on a boat.

What are the advantages disadvantages of living on a boat?

Curious asked: We are in England or could be Ireland. We know nothing about boats but wonder if the lifestyle would suit us. We wonder about the costs involved, doctors, poll tax, where do you get rid of your household rubbish. where does the fresh water come from – we know absolutely nothing, [...]