The term originated from the occasional black sheep which are born into a flock of white sheep due to a genetic process of recessive traits. Black wool was considered commercially undesirable because it could not be dyed. In 18th and 19th century England, the black color of the sheep was seen as the mark of the devil.
The transom is the flat back end of a boat. Some boats are pointed on both ends, so they have no transom. A traditional canoe, pointed on both ends has no transom. A modern square stern canoe (made to take an outboard motor) has a transom.
After a while, the plywood begins to rot and delaminate. Long term, the plywood in the transom looses strength and becomes very flexible, allowing the gelcoat and fiberglass to crack. While it is a pretty complicated job, replacing the transom core isnât impossible. Transoms are usually replaced from inside the boat. This means removing all the internal structure, seats, and tanks, etc. so you can work on the transom. If the boat is an I/O, that means removing the engine. Once you can get to the transom from the inside, it is time to cut away that inside layer of fiberglass. This needs to be done in a way that doesnât stress or crack the exterior fiberglass layers and gel coat. An angle grinder with a cut-off blade works well.