How do you tune a boatswain call for the royal navy?

Answer:

A Boatswain's call or Bosun's pipe was used aboard ships for communication

It can be tuned by modifying the tube, by flattening to make the space near the pea smaller
Another way to tune is to push something into the pipe to sharpen the edge
When tuned and held with the mouth toward a breeze a sound will be heard

First answer by Kowhai2. Last edit by Kowhai2. Contributor trust: 11 [recommend contributor recommended]. Question popularity: 2 [recommend question].