One of many flags presented by the State Library of Tasmania is that of a firm named Brown Bros. (Brothers):
Red field, blue diamond touching the flag’s edges and bearing a white initial "B" without serifs.
It is stated that this company owned the ship Stephen Brown although Coal and Allied Shipping is also named in this capacity. A pennant of this vessel may be seen at this State Library page:
Caption: “Navy blue pendant flag with 'Stephen Brown' in white lettering. A paying off pendant was made when a ship finished its service, and the length of the flag is 1ft for each year of service. The 'Stephen Brown' was a 60 miler that carried coal from Newcastle to Sydney before being sold to the AMC (Australian Maritime College).”
Surely this is a simple onomast also known as name pennant, not a paying-off pennant as used by a navy?
“Brown Bros.” is connected to “J. & A. Brown and Abermain Seaham Colliery Ltd” of Sydney – see this Aberdeen Built Ships page about what must have been the ship in question.
See also Coal & Allied. This firm was founded after the merger of Brown & Abermain Seaham with Caledonian Collieries in 1960. In fact Abermain and Seaham had merged in 1922 joined by J. and A. Brown in 1931; the largest shareholder was Adelaide Steamship.
Additional info: CareerOne page on Coal and Allied and entry for photo of Abermain No.2 Colliery at Demetrius repository, ANU. The above seems to indicate pre-1960 use of the house flag, the name pennant may have been in use after that.
J. & A. Brown. Engaged in the coal business after emigrating to Australia in 1842 and becoming involved in shipping by 1857. The flag, from The Log 11/1987, was red with a blue diamond throughout bearing a white " B" which was retained when the company amalgamated in 1931 into J. & A. Brown Abermain Seaham Collieries Ltd., and even lasted into that company eventually becoming Coal and Allied Industries Ltd., until 1980.
With regard to the ship "Stephen Brown" it was built in 1954 for J & A Brown & Abermain Seaham Collieries and consequently passed to their successor Coal & Allied Industries Ltd. before being sold in 1983 to the Australian Maritime College for mooring as a training ship. I agree with Jan that it is unlikely to be a paying off pennant and the use of individual name pennants basically went out with house flags. My pick is that that it has nothing to do with the ship's working career in the coal trade but was given to the ship when it became a training ship for AMC. The flag held by the Museum is in excellent condition – too good to be 27 years old I would have thought.