Minecraft wiki entry for Skeleton_Horse, associated text: Dr. Zhark appears in the credits after the End Poem as the creator of the horses, including skeleton horses.
In Bedrock Edition, skeleton horses can be transported in a boat by riding the skeleton horse and jumping into the boat then dismounting (leaving the horse behind in the boat) and activating the boat from underneath/underwater. Attempting to activate the boat in order to pilot it from above results in the player being mounted on the horse again rather than being placed inside the boat to pilot it.