After the earlier tutorial on islands, I was inspired to create a tutorial about the ships that explore them. It's not a particularly complex ship, but it gives enough pointers to help a GM render their own ships for campaigns.
Most notably, we introduce the concepts of wood grain, crates and barrels. These are details that I love to add into my maps, providing points of interest for players to latch onto.
I've fiddled with the contrast on this one to show the pencil lines a bit more clearly.