The dd-rescue package on linux should work just fine. Assuming you can get the disk to respond. If the disk is taking 180s then the disk is not responding at all, and even if the disk were responding in 10 sec any rescue program will take longer than anyone will wait. The software tools will only work if the disk is bad sectors, with the disk not responding at all that makes it more likely the disk is simply dead, or the power supply/usb controller is dead.
Best plan would be to get it out of the usb enclosure and see if smartctl will return anything useful and see if the disk behaves better.
well, when it's dead, it might be dead for smartctl command's too.... No ? ;-)