Sentence:  Crossing the 4000 - foot width of the Mekong at Champassak , on a <WSD>raft</WSD> with an outboard motor , we took off our dusty shirts and enjoyed a veritable ocean breeze . 
Meaning of the word marked with <WSD> tags:  a flat float (usually made of logs or planks) that can be used for transport or as a platform for swimmers