While in Sydney, I visited the Australian National Maritime Museum, located at Darling Harbour. It was a filthy day and, while I was there, there was a colossal thunderstorm which caused flash floods in and around the area. By then, I'd seen all I wanted to but stayed put until the worst of the rain had stopped, lurking in the shop. The shop had a decent selection of books and some pretty good ship models too but I refrained from buying any because of budgetary restraints as well as considering the fact there was a possibility my baggage could end up exceeding the airline's restrictions (Malaysia Airlines only allow 20 kg of checked bags and a measly 7 kg of carry-on luggage if you're in steerage class).
I paid $27 to go in, which allowed you to visit the ships they had on display, including HMAS Vampire, a Daring-class destroyer, and HMAS Onslow, an Oberon-class submarine (if that sounds familiar, the Royal Navy had Oberon-class subs until the 1990s).
I visited HMAS Vampire first, because there were some threatening clouds coming in from the Pacific Ocean so visiting the ships first then heading inside looked like the best option.
Other ships
A few of the inside exhibits
A model of SS Orcades
Surfing - Australia is one of the word's foremost surfing locations.
A former RAN helicopter