Swam our horse up beside our schooner, held E over the tame and selected the "Load onto ship" option. After a moment of searching, I checked the company logs and saw that the tame was killed. I can only assume that it was accidentally deleted from existance instead of peoperly being placed on the ship.
server: NA PVP Krakens Maw
location: cheat TP K8 142617 249449 302
Things to note: The tame was overburdened. Not sure if that would have anything to do with it.