[scott00]

How common are scenarios where there are multiple ships within visual distance? From reading the account of the collision, it seems like everybody relied primarily on one radar to make navigation decisions, and that radar was either broken, or its operators didn't know how to use it. It's hard for me to understand how they didn't realize they weren't getting useful data from that radar and switch their primary navigation driver to the other radars, lookouts, the commercial position broadcasting system, or the infrared camera, all of which seemingly worked. Unless of course actually navigating around other ships is pretty uncommon.

[genkimind]

Navigating with other ships in close proximity is pretty common -- mostly when transiting into port, out of port, and through shipping lanes.

It is pretty silly that they didn't seem to realize that the radar wasn't tuned correctly. I wasn't a surface watchstander so I can't comment on the radar aspect in more detail. Normally inputs are taken from a variety of sensors, not just one busted radar.

[scott00]

So is it like a every day kind of thing or like a few hours every week or two weeks?

[pdonis]

It depends on what the ship is doing. When a ship has to transit a high traffic area it generally takes at least several hours, and possibly many hours. This will happen every time the ship goes into port or comes out of port (the USS Fitzgerald was coming out of port), and it will happen whenever the ship has to transit a high traffic area to get wherever it's going (the USS McCain was transiting the Straits of Malacca, one of the most crowded shipping lanes in the world, when it had its collision). Those things are probably happening more often nowadays than they did during the Cold War, because more of the jobs Navy ships are being asked to do are close to shore instead of out in the middle of the ocean.

[genkimind]

It depends on the ship, but given the underway scheduling for DDG's in Japan, generically and loosely:

Repeat every 3-8 weeks randomly with gaps of 6 months every 2-3 years:

    2 hours of leaving port

    1-3 weeks later: 2 hours of entering port

[pdonis]

> How common are scenarios where there are multiple ships within visual distance?

In a main shipping channel near a busy port? Very common.

> It's hard for me to understand how they didn't realize they weren't getting useful data from that radar and switch their primary navigation driver to the other radars, lookouts, the commercial position broadcasting system, or the infrared camera, all of which seemingly worked.

Or the old standby, the Mark One eyeball. As I commented elsewhere upthread, the thing that jumped out at me was not having a lookout on both bridge wings (port and starboard). Even with a ship that's shorthanded, that's the last place you should give up personnel, especially when navigating in a crowded shipping channel at night. They should have made up the shortfall from somewhere else.