Yes the timing was very important. My late grandfather was an engineer on a trawler out of Aberdeen. on one trip some cotton waste fell into the sump. as he thrust his hand down to retrieve it the trawler gave a violent roll and he miss timed it. engine took the back of his head off. My Father who was a stoker on a sister trawler got his orders from his mother to get out of engine rooms. hence he worked on deck and eventualy got his ticket there. Steam is fascinating, but, must be treated with respect.
"Imagination is more important than knowledge". A. Einstein.