Link by boat Madagascar / Reunion / South Africa... possible ?

I’m sure there are commercial vessels but they are generally cargo only. There is an open Facebook page called Sailing South Africans where you can post a request. There are always boats going to Mozambique, Madagascar, Seychelles etc. Charter boats are expensive, but private ones often take people if they cover their costs (food etc) and help with the boat in some way, even if it’s cooking and cleaning.

Greg