Most companies dont actually list properly that they recruit for companies or their sites are based on java scripts that doesnt always show up in Google searches. So what is a person to do...?
Well, there are a few ways to approach this, either ask a friend who was/is there how they got intouch, search for blogs by crew members or ask in the forums of your related industry. On Gearslutz for example the question was asked and a guy got his answer a few days later.
Be sure to be specific in your Google search though.
For Saffas there are a few companies that do recruitment. Carnival Cruise Lines has their main recruiter in Cape Town called Blue Ensign (well, to me they are the main company because most people I know that work for them went through Blue Ensign.)
Royal Caribbean had two calling points but as of late the fastest was to go through Hospitalio. They also have quite a bit of info on their site that you can have a look at regarding how things work and what you need to expect.