The picture you post is typical of the Nigerian Pirate Flotilla. They have info regarding Gasoline / Gasoil vessels due to discharge in Nigerian River ports ...
While ship is coming alongside tieing up - they lay in wait under the jetty's or just up-river. Once ship starts discharge - they tap into the line under the dock and fill up the canoe !
My partners offices out there have to contend with this open piracy and they have joked about "Malrboro Man" sitting in the canoe with a few tons of gasoline slopping around under feet.
When first seen - you can't believe anyone could do it ... but yes it is true. And a lot of cargo goes missing this way as well !