Of course a UK owned ship will show a UK IP address, especially since its not fixed line as stated above, they will be using some form of satellite / wireless back to a UK provider.
But if you are using fixed line internet in the USA (like a hotel will have with a US ISP), there is no way whatsoever it will show an Australian IP address.
I also highly doubt you were using a hotel's internet in Singapore and it showed up as another country. Seems very implausable unless they were using an overseas ISP / VPN for some strange reason.