Why doesn't every cruise ship have a overboard detection system? | Hacker News Reader

Why doesn't every cruise ship have a overboard detection system?

usatoday.com

24 pointsthunderbong17 comments

A big issue after someone goes overboard even if they know right away is finding the person. Specifically in the middle of the night. Without the proper long range thermal vision you have no chance of finding someone. They can see you, you can't see them and on a large ship it is probably pretty much impossible to get it silent enough to hear someone's calls. Lage ships also take time to slow down. It's possible for someone to already be far away even if a detection system cuts the engines right away.

They'd need drones equiped with thermal vision that can at least drop some buyoant object at the target

Not sure why you are getting downvoted, at least visually spotting doesn’t seem like a bad application for a drone.

At the risk of writing one of those smugly ignorant HN comments with a poorly thought out "why don't you just" solution in it...

That actually sort of does. An observer hits a MOB alarm, like a fire alarm point, and that causes the deployment of a few drones with infrared cameras that start circling the ship in an outward spiral. Even in the warm waters of the Carribean a (live) human is significantly warmer than the water and I think should stick out. Tracking a light blob on a dark background feels like it ought to be fairly basic CV (though I don't know for sure). The drones can take it in turns to loiter, tracking the MOB. Perhaps a larger drone might then be launched to fly out and drop a flotation device.

At the very least something like this may help to provide a better location fix on the victim.

But again I don't know - probably there are all sorts of complications to spotting people in the water using infrared. I am sure a former Coast Guard SAR pilot will be along in a minute to tell me why I am wrong - I look forward to being educated :)

Someone on Reddit suggested that if you see someone fall over board, one group of people should keep their eyes 100% on where the person is, not looking away for even a split second. Meanwhile, another group of people should start throwing things over board. The moar things floating in the water close to where the person fell over board the better. Those items can help improve chances of finding the spot where the person was lost, and also the items might float in the currents in similar directions that the person might.

Someone also pointed out that often times there are a lot of fishes following the ship, and sometimes even sharks! If they are unlucky there might be sharks in the water :(

When I was doing my sailing license one of the mandatory training thing was a 'person overboard' maneuver. And the very first thing you do is to designate someone from the crew to point (with a finger and arm extended) and look at the person in the water at all times

So when someone falls overboard the ship could auto deploy floating devices and a trail of floating signal lights/markers. It could also mark the exact GPS spot and alert the crew. After that they could mount a rescue.

The hardest part would be detecting that its a person who's fallen overboard.

You could have people carry devices that trigger the alarm when they get wet and are a certain distance from the deck or use optical sensors - though I think they'd fail more often, especiallyat night.

In a perfect world the detection system would launch a net and cast the person before they hit the water

The problem is that all these things cost a fuck load of money and in this industry if something isn't made mandatory by law it's going to be skipped

The throw stuff over and point is basic training in all seamanship courses.

A boat as big and fast as a cruiseship generally won't have fish following it though. It would take a LOT of energy to maintain that pace.

You can buy devices that trigger an MOB signal over AIS when the wearer falls overboard. I have one for each member of my family when cruising on our boat. They deploy automatically when wet/the PFD inflates, and the specific message they emit triggers alarms on AIS receivers and marine radios:

https://www.acrartex.com/products/automatic-identification-s...

There's also cheaper devices based on Bluetooth. When the wearer falls off the signal range, the bluetooth base & the wearer's bluetooth beacon start beeping and flashing lights.

This is stuff that has good solutions for. However when you fall overboard, even if your location is known... recovering you is quite the challenge. It's a challenge on yachts which have much lower freeboard. Imagine in a giant cruise ship with hundreds of feet high boards, and momentum that requires 20min to stop the ship.

Boats above a certain size don't recover the victim themselves, they launch a rescue boat for that. Much easier than recovery on a pleasure craft.

I used to captain a tall ship, and that's the way that every one of us did it. It's way too hard and slow to maneuver even a 100 ft. boat to a MOB. We could heave to and have the rescue boat in the water in under 120 seconds.

If you go over without a life-jacket and a light, like most cruise ship passengers, your chances of recovery are almost nil. It's kind of a miracle that they find anyone at all. I wonder if the statistics cited also include MOB events at the dock, where if you survive the fall, your chances are pretty high.

> It's possible for someone to already be far away even if a detection system cuts the engines right away.

If you see someone go overboard you're told to keep your eyes on them, point and shout man overboard repeatedly until a crew member passes on the alert. Then depending on if the person is seen a life boat can be launched or the ship will turn and circle.

Would small but fast deployable and fast moving emergency boats, coupled with powerful light emitters not solve the issue? Also nets surrounding the boat may help prevent people reach water.

Similarly, people paid to monitor for people falling overboard may help.

With many other things, I'm sure it's to maximize profit.

"he remembered having some drinks and winning an air-guitar competition before waking up in the water."

What a night.

He was dramatically overserved (thanks to the author of this article for adding that to my vocabulary!)

People on ships are meshed with sea going wisdom from inception of the sport and so know you do not leave behind a shipmate... every few weeks ship conducted man overboard practice sessions so next time it happens Bingo

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