Tiwi Islands - Call the River Police!
In my ongoing mapping for the books for Expedition 360 - the first human-powered circumnavigation of the world I just drafted up Jason's route through Indonesia, from Darwin, Australia to Singapore.
After leaving Darwin, Jason peddled through Apsley Straight, through the middle of the Tiwi Islands. I'll let a map do the talking (from mediawiki):
Apsley Straight is between 550 metres and 5 km wide, and 62 km long.
Love that current! From a boating guide I found, The currents run at up to 4 knots on spring tides with the flood tide running south, and the ebb tide running north.