I am looking for the title of a short story where a space craft is made up of various creatures from around the universe.
If I remember correctly the skin of the craft is made of creatures. the computer is just a giant brain. The engine creature suffers some form of malfunction and a nearby suitable replacement is located which happens to be a human. Although not as good as the original the human will suffice. At first he is reluctant but then discovers he loves it. I think they call propelling the craft as "pushing".
I hope somebody can help. I had this book many years ago and I don't know what I have done with it.