The Moiré Effect Lights That Guide Ships Home

The Moiré Effect Lights That Guide Ships Home


It’s difficult to research something if you
don’t know the name of it. I got an email a few days ago asking if I
could figure out anything about this. And normally, I try to discourage
messages like that, I’m not Google and I’m not a reference librarian, but this thing completely nerd-sniped me. Because other than one reference on Wikipedia to this exact light that’s for shipping on
Southampton Water, I couldn’t find anything about it. Which is weird, because this
is a really clever idea. This light is based on moiré patterns, which are the extra lines and patches that
seem to appear when you have two similar but
slightly different patterns overlaid on each other. You see them in a few places, but most of
the time they’re confusing and distracting and designers want to avoid them. But here, the patterns are set up so that if you’re looking straight at that light,
dead on, you see parallel lines. But if you’re to either side, the arrows formed
by the moiré patterns tell you which way to go to be
straight-on to it. You can have five different boats in five
different locations out there, all looking at the same sign, and they will
all see arrows pointing the right way for them, without any
computers or fancy tracking. This seems like such a good idea that I couldn’t
believe it wasn’t well-known. So I went searching. “Moiré shipping light.”
“Moiré boat light.” And after a half hour or so, I’d found a couple
of others around the UK, placed at the entrances to locks and marinas, or at the end of dredged channels,
so that people steering a boat know exactly which way to go
to avoid the sides. One guide for mariners called it
an “Inogen light” but that just led me to a medical company,
nothing else. And that was it. It looked like a bit of weird maritime history that had been a brief fad and then died out,
leaving no trace. A beautiful idea that the world had ignored. I considered starting a new series of videos
called “I Don’t Know” just to see if anyone knew more about it,
because it’s genius and, yeah, I wanted to understand it. So much that my brain wasn’t quite done,
I kept coming back, I kept searching. And eventually, I started looking through
patent databases. And after a few minutes, I found it. It was patented by Lars Bergkvist and
Ivan Forsen, from Sweden, in the late 1970s. They’d invented several things to do with
moiré patterns, between them. And though there are
a few more patents after the first, refining the idea or making it work
in two dimensions with circles, the trail ended there. I tried to track Lars or Ivan down,
and couldn’t find any trace. The only thing I had was an address from about
forty years ago. And in Sweden. And then one little clue, spotted just out
the corner of my eye, unlocked everything. Yes, this was patented by Bergkvist and Forsen, but the patent was then assigned to a company
called Inogon. Not Inogen — that was a typo,
or a corruption of the name over time. Inogon. This is known as an Inogon leading mark, or
just an Inogon light. And once you know that, once you name it,
you can search for it. You can find the US military analysis from
1986 testing that it works. The variations that were made for getting
an aircraft into the right place parking in a stand. The Swedish company called FMT
that now makes them, or did until recently, because they’ve just
removed it from their web site. Once you know that this is an Inogon light, all the rest of the research becomes easy. All except one thing. This Inogon light isn’t being used to guide
people in. The light follows the path of an underwater
cable where you shouldn’t drop anchor. So the signal here is all wrong. You don’t want to follow these arrows, you’re required to stay away from them unless
you’re passing straight through. It’s a really weird use
for a very expensive light. So why is it here? I don’t know. But if anyone out there does know, for sure,
with evidence… do get in touch.


100 thoughts on “The Moiré Effect Lights That Guide Ships Home

  1. The inogon light that works backwards, as in your video, is easy to find if you know it’s secret name. The backwards inogon is called the NoGoIn light.

    Ba-dump-dump.

  2. that could work for 3D screens, it already works with those "magical two-side 3D images" in toys and cards.

  3. you'd think they'd have made it an X telling people not to anchor if they can see the X, assuming you can create an X using this

  4. Surely that light would have been used to guide ships in while it was under construction? So the ships knew where the cable was

  5. Range markers are used to mark a channel by lining up two lights that are above one another. The reason they used the Inogon leading mark is to have a visual for where a cable is and not to set an anchor on it. This was a way to mark that spot and use something that would not be confused with a range marker.

  6. Hi tom there's an underground cable and the inogon light is to makesure people dont drop anchors on it.

  7. Over here, we just put up a large I mean LARGE sign on either side warning of a cable crossing, 'don't anchor and please do not sink here' kind of thing.

  8. Aircraft use parallax for things like precision approaches and parking. Again no fancy stuff needed. I made one for parking in the garage.

  9. I didn't know these were used for ships. I've seen them many times at airports for the aircraft parking bays. Though nowdays they're being replaced by electronic displays with some kind of active sensor system.

  10. It's ironic that good technology is often discarded in lieu of pseudo-progress fashionablism. Progress isn't always linear, continuous and forward, even with Moiré arrows showing which way to go.

  11. Belgium uses these to warn drivers about sharp turns on the high way because they appear to be flickering.

  12. The arrow Yellow and Black indicate were danger is. In marine books with signs you can find this.

  13. Too right about trying to find something out without having a key word or phrase. I've been trying for years to find a phrase I heard once that describes a situation where a product cannot be improved but innovations are needed to stay ahead of the competition. Apparently toothbrushes became perfect for their function years ago. But manufacturers have to keep changing the design and saying it's an improvement to try to sell more than their competitors.

  14. The patent should be up by now, if nothing else makers and other such people can make their own without fear of being sued.

  15. "so were going to need a buoy and a flag to mark this cable so…"
    "but guys i found this flash thing that will use more of are budget!"
    and this is why England has silly things

  16. It's odd that you didn't interview mariners asking if they knew the light, its purpose and instruction.

  17. So I looked up Lars A. Bergkvist and Ivan Forsen, and I think I found them both. 81 and 79 years old. Not that difficult if you're a swede.

  18. I think the reson its not so popular is dueto the one you are standin infront of they wehre put into use before it was implamented in meritaime law

  19. So protecting a very expensive cable with a very cheap light somehow bemuses you? 🤔
    Hmmmmmm 🤦🏼‍♂️🤦🏼‍♂️🤦🏼‍♂️

  20. I KNOW! I KNOW! Satellites dont exist most communication is done through undersea cables and there happens to be a very important cable crossing right there. Boat anchors can get caught on and damage the cable.

  21. It’s taking all the strength I have not to hum the old Harlech ident music when you show the effect…

  22. Dude I love your channel, really interesting stuff.
    Thank you for your effort in making good content, keep the vids coming 😊👍

  23. Perhaps it was there previously to Do what it's supposed to do but isn't used and more but just assent been taken down

  24. This unit could be a back up to radio navigation, like airplanes use. Even with airplanes, a radio failure can be over come with light signals.

  25. Is this question still unresolved 16 months later ? Surely the Southampton Harbourmaster would know the answer as to why that particular light is being used in an abnormal way, have you asked them ? Also, it looks relatively new and therefore all shipping and boat captains who use the harbour must have been briefed when it was introduced and told what it's intended purpose was for, have you asked any of them locally in the boating community ? Find it hard to believe that this question is difficult to find the answer to.

  26. It might be there for the pipeline company to locate their pipes from anywhere in the river. If the local boaters don't know what it's purpose is then the light is probably not intended for them.

  27. This effect is visible on the A50 in stoke on Trent UK on most of the over carriage walkways. I don’t think it’s intentional but it’s very interesting to see.

  28. Hi Tom, in maritime navigation, navigation aids always shows where the danger is. Since people have been going to sea, they have placed fires on dangerous peninsula, that are now light houses. Nowadays, there is a navigation aid called "isolated danger" (red and white marker – to simplify). That marker indicates where the danger is, and leave it to the seafarer to decide what is the best way to avoid it. Based on that principle, the arrow shows where the underwater cable is, and not where the boat should be going, that is a decision left for the responsibility of the seafarer. Hope that helps. (If they – the organisation in charge of managing those navigation aids- tell you where to go, then their responsibility is engaged, that is why they never do it).

  29. Look at the building its sitting on…. Its and under-water fibre optic or power cable landing. Joining and termination point in the building.

  30. I think the reason the inventors are hard to track down is because from what I can tell they both died in 2015… 🙁

  31. A stunning example of a Moire effect can be seen in Hitchcock's film: To Catch A Thief. Cary Grant plays a cat burglar, who's Moire shirt shimmers so much, you will want to adjust your TV.

  32. This is a frustration I have all the time when trying to find the name of something, and I have to use description instead and hope the search engines give me what I am looking for.

  33. I mean I'd argue that in this case it's not telling you to go in a direction it's just telling you that the line is in that direction, which would be clear if you had a shipping map or marine chart in conjunction with it, another possibility is that it's for maintenance of the line and not in fact aimed towards sailors. Have you tried contacting commerical fisherman that frequent the strait?

  34. There are moiré guider arrows used on some dutch motorway ramps with tight corners, they flicker a bit when you approach and the shape of the arrow changes. I have seen them although I can't find where they are exactly

  35. When I was a kid my dad had these little cast pieces of art from a friend who used this technology to create paintings. It was incredible to look at and hold. It used only shadows and reflections from the sun

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