There are two distinct type of bosun pipes, English and American. The English version has a larger bowl, and a Bottom fin which attaches to the stem of the pipe. The American version has a much smaller bowl, with no fin attached. The pipe was used to call out orders to the sailers when the voice would not carry the wind. Such as an order to shorten sail. They were used to pipe aboard officers of rank, such as capt. admirals, comidors, ect. This was more than just a salute, it was to let every member of the crew know who was aboard or leaving the ship. It would also call a fighting ship to battle, and give orders to sailers under the gun who could not hear voice comands. Before you blow your lungs out on an English pipe, I would attemp to tune it. You should very gently put two dimples on each side of it with a ball pien hammer. This will cut the amount of air it takes to get the pitch. Then melt some bee's wax and thinly pure some into the bowl and keeping the bowl hot shake out any excess. This also helps to reduce the amount of flow, and by increasing or decreasing the amount you use you will get the pitch you need.

As for the calls, it also depends on if your English or American. I would suggest you find an old bosun who will be more than happy to give you a tune or two.