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.
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