A chalker is a slur against white people, when you're so white it needs a new slur that you can slap a hard R on. When your dad's dancing is so bad that whatever amount of melanin he has turns to dust and leaves his body.
A man who ties up pieces of rope filling holes in a ship or boat. Along with this he puts a tar-like substance into the hole so the water doesn't leak in when more water pressure is added.