How they make propeller shafts on large vessels like ocean liners or aircraft carriers waterproof considering the intense water and mechanical pressures that come into play?

Question

It seems like a grommet-type seal would fail in no time. Also, looking at an image of one of the propellers for the Queen Mary, it hit me that this is decades old, and would have to go to dry dock to be serviced, and there is no way they are doing that so… How is that even possible? I’d figure dry rot would set in somewhere along the way.

In: Engineering

Answer 1

The same kind of seal they have on ship’s propeller shaft, a packing box is also used on gate valves. Here is a video of a man repacking one. [https://www.youtube.com/watch?v=hvfvNjSXzcY](https://www.youtube.com/watch?v=hvfvNjSXzcY)