It is irrelevant whether the "Ram Sethu" was man-made or is natural, what is relevant is that it does not make nautical sense.
In the case of the Suez and the Panama canals, ships save thousands of nautical miles in sailing distance and hundreds of hours in sailing time vis-a-vis the Sethu Samudram where a ship will probably save a few hundred miles and at the most two hours in sailing time. This is the difference.
"The Sethu Samudram does not make nautical sense".
-- Captain (retired) H Balakrishnan of the Indian Navy --
