http://navionics.com/en/webapp (Click on Navionics+ ; then, on South Indian Ocean; then go to Maruitis; and start zooming around.)

You'll see that there are bunch of items that give one a clue that there are features in the ocean. In fact one is in a region where their course would have been along the series of interrupted "ridges".
The "blue circled area on the image below is from an UNDERZOOMED chart. You can see that "things" are happening on the chart. At the least there would be, with a current that is flowing from east to west across the major changes in the ocean, a bunch of sea state conditions as thousands of feet of water depth begins to rapidly reduce.

For me, absent being so exhausted that I became incurious, I couldn't have resisted to explore the digital information with my mouse and keypads. I KNOW THAT'S EASY TO SAY IN REFLECTION! I've gone aground RIGHT where the chart said I should myself ;^))). Shit happens, but it's useful and beneficial to reflect on how we might avoid experiencing such suffering. They were pretty lucky that no one was lost or injured.

There are some places that "No Detailed Charts Available" are noted just outside the delineated area to the east beyond the "red line". I'm struck by the areas that say "Sorry No Detailed Chart Available" -- there are some "blue" tones lurking tones in the Navionics chart in relatively shallow water. I wonder what that might mean....

In this case, the place where the crew hit is an area that is sufficiently charted to warn one of the danger.

I note these things not to be critical of the crew. Rather, to point out that there is a lot of useful information that is readily available if one uses the AMAZING tools that we are afforded with today.

Who'd have though that we could simply roam over oceans from our little relatively inexpensive computers and displays and look at such detail of places half-way around the world that most us didn't know existed. When you tie that with Google Earth and other such services, you can get amazing perspectives on parts of the world that the vast majority of us will never see in person.