Q&A: How deep were Triton's Indonesian passages?

How deep are the channels around Indonesia for a submerged submarine?

Some routes, including Lombok Strait, were deep enough for submerged transit, but strong currents, coral shallows, narrow passages, and uncertain fixes still made the journey hazardous.

The Indonesian passages cannot be reduced to one depth figure. Triton's survey helped establish where a submarine could safely travel underwater. Pearl Bank required a narrow deep-water gap, reliable position fixes, and careful control of periscope exposure. Lombok Strait offered deep water but currents strong enough to reverse a wartime submarine's progress even at maximum sustained submerged speed. Charted depth and actual operating conditions therefore had to be considered together.