A distinctive feature found on Liberty ships is the steam whistle mounted high on its
smoke stack that produces a deep resonant tone. The sound generated by a steam
whistle is created when steam is emitted through a circular orifice about 1/16 inch wide
at the top of the whistle valve just below the bottom of a cylindrical bell housing. The
principal is the same as when a person produces a tone by blowing across the mouth of
an open bottle. All ships are required to have a whistle as a means of producing
audible signals and warnings. Now that most steam vessels have been replaced with
diesel-driven ships, the electric horn has become the standard on most ships rather
than the steam whistle.
On the Liberty ship JOHN W. BROWN the steam whistle is still used to make audible
signals. This type of whistle generally requires little maintenance. It is designed to
operate in all weathers and has few moving parts other than a steam valve and a
linkage so the valve can be operated remotely by the watch officer from the conning
station. However, when the midships house was painted recently, paint got into places
where it wasn’t intended in the ship’s whistle.
The flexible sections of the operating linkage where it passes over pulleys is made of
linked chain similar to bicycle chain. The painted chain links made them stiff and
prevented their movement over the pulleys
The steam orifice at the top of the valve was completely obstructed by paint so the
steam wouldn’t flow through it. In short, the whistle wouldn’t work.
To restore its operation, the offending paint was removed from the flexible portions of
the operating linkage. New fittings were fabricated at the ends of the chain segments
and they were joined to lengths of stainless steel wire made from old sailboat stays to
restore the flexible linkage. Up on the stack, the heavy cylindrical bell housing of the
whistle was removed to expose the steam opening and remove the paint from it. The
whistle was then reassembled and tested. After adjusting the height of the bell housing
above the top of the steam valve to achieve the desired deep resonant tone
characteristic of Liberty ships, the whistle was back in operation.
This is just another interesting task in maintaining a 73-year old Liberty ship in operating
condition.
Project Liberty Ship, Inc is a 501(c)3 non-profit, all volunteer organization engaged in the preservation and operation of the historic ship JOHN W. BROWN as a living memorial museum. Gifts to Project Liberty Ship are tax deductible.
