Obviously, I would want enough people that the piano will go down gently instead of imploding to pieces but in one of my stories, there is an abandoned houseboat with a grand piano and unfortunately no dollys around. The piano itself is about 800 lbs with no wheels. A pianist wants to move in to the houseboat but it has to be in shape first. Unfortunately, the wood floor is very old and rickety so somebody has to replace the entire floor which means the piano has to be taken out before it falls and causes the boat to sink.
The piano is one of the best quality pianos there is so if the piano implodes into pieces, that is going to be a steep price for a new piano. So, this motivated me to ask this question. First off, how many people at minimum would it take to lift an 800 pound piano? Would 4 be enough? And second, how many more people are needed to make sure the piano does not implode into pieces when it is set down?