- Author
- Letter Writer
- Subjects
- History - general, Letter to the Editor
- Tags
- RAN Ships
- None noted.
- Publication
- December 2015 edition of the Naval Historical Review (all rights reserved)
The following interesting letter has been received from our member Roy Kingston of Castle Hill.
On 10 September I had the privilege of attending the ‘launch’ of the public display of saved ‘pieces’ and the Naval Historical Society’s DVD chronicling the history and demolition of the Hammerhead Crane at Garden Island that had proudly dominated the Sydney skyline for over 60 years.
It was billed as a ‘launching’ ceremony but to me it was a celebration of a complex project brought home safely, successfully, and with great historical sympathy.
Of special interest to me was that the rotating electrical machinery (read DC variable speed electric motor) had been saved and is now on public display for the first time since it was built. This DC motor was built by the English company British Thomson Houston (BTH) who, incidentally, continued to break new ground in marine engineering in supplying the P&O liner Canberrawith her turbine-driven AC alternators in the mid 1950s, another world first, but that is another piece of marine engineering history yet to be told.
The DC variable speed motor as fitted to the Sydney Hammerhead crane was on the cutting edge of electrical machinery development in the late 1940s/50s. It required complex control equipment, special windings, and brush positioning equipment, not to forget special skills in operating it. The variable speed motor in the 1950s was a very advanced and expensive technology, and not available on a more economic basis until the mid 1970s with the introduction of thyristors, an offshoot of the electronics era. The fact this motor was supplied to Australia as a crane component required a lot of specialist and new skills in fitting and wiring it up, which says a lot about the abilities of Australian engineers of the day, both mechanical and electrical.
It also should be remembered the local engineers would have been working, in the main, off General Assembly drawings (GAs) and complex circuits, a lot of which would have been new to them. They would have used their engineering ingenuity in getting all the components together, aligned, wired up and working. In the main the means of communication would have been by surface mail to the UK and back, meaning it could take all of two months to get a reply on a technical query, providing another layer of challenge. At the Garden Island launch I had the opportunity to speak to the son (Warwick Stuart) of the man who owned and ran the engineering shop at Marrickville, and did the work on the Hammerhead. This could be another story all on its own.
The best of my research indicates only five Hammerhead cranes were ever built using these special motors. One of the surviving examples of the Sydney Hammerhead-type design, albeit smaller, is found on Clydeside at Glasgow, UK, where it has been refurbished and is now a tourist attraction well worth visiting. It was my hope the Sydney Hammerhead crane would follow this example but for various and good reasons that could not be. The RAN Historical Society has done the next best thing in displaying the key components and documenting it with a DVD. The effort put in by Commander Jeffcoat, RAN giving us some of her valuable time made this a most memorable occasion.