You will be surprised how much garbage a ship can produce.
Especially plastic and other non bio degradable material.
In earlier decades, everything was thrown overboard, up to crude oil, ammunition and even gas shells and nuclear waste.
Since years, we have a Garbage Management Plan and you are not allowed to dump any (non-food) garbage at all in certain areas.
We are getting closer to the African continent now, and the majority of people living there, never heard of garbage management. The result is that we will encounter plastic littered stretches of water. It is not only African garbage, a substantial part of it is imported from western countries. We will keep our garbage on board and transfer it to the shore in Angola. Only wooden crates are burned in an empty oil drum on our aft deck.