WEBVTT
Kind: captions
Language: en

1
00:00:00.099 --> 00:00:03.139
It's difficult to research something if you
don't know the name of it.

2
00:00:03.139 --> 00:00:07.149
I got an email a few days ago asking if I
could figure out anything about this.

3
00:00:07.149 --> 00:00:09.530
And normally, I try to discourage
messages like that,

4
00:00:09.530 --> 00:00:11.590
I'm not Google and I'm not a reference librarian,

5
00:00:11.590 --> 00:00:15.070
but this thing completely nerd-sniped me.

6
00:00:15.070 --> 00:00:16.650
Because other than one reference on Wikipedia

7
00:00:16.650 --> 00:00:20.590
to this exact light that's for shipping on
Southampton Water,

8
00:00:20.590 --> 00:00:22.890
I couldn't find anything about it.

9
00:00:22.890 --> 00:00:26.030
Which is weird, because this
is a really clever idea.

10
00:00:26.030 --> 00:00:28.699
This light is based on moiré patterns,

11
00:00:28.699 --> 00:00:31.500
which are the extra lines and patches that
seem to appear

12
00:00:31.500 --> 00:00:36.879
when you have two similar but
slightly different patterns overlaid on each other.

13
00:00:36.879 --> 00:00:40.800
You see them in a few places, but most of
the time they're confusing and distracting

14
00:00:40.800 --> 00:00:43.159
and designers want to avoid them.

15
00:00:43.159 --> 00:00:45.789
But here, the patterns are set up so that

16
00:00:45.789 --> 00:00:49.820
if you're looking straight at that light,
dead on, you see parallel lines.

17
00:00:49.820 --> 00:00:53.910
But if you're to either side, the arrows formed
by the moiré patterns

18
00:00:53.910 --> 00:00:57.000
tell you which way to go to be
straight-on to it.

19
00:00:57.000 --> 00:00:59.870
You can have five different boats in five
different locations out there,

20
00:00:59.870 --> 00:01:02.879
all looking at the same sign, and they will
all see arrows

21
00:01:02.879 --> 00:01:07.479
pointing the right way for them, without any
computers or fancy tracking.

22
00:01:07.479 --> 00:01:11.689
This seems like such a good idea that I couldn't
believe it wasn't well-known.

23
00:01:11.689 --> 00:01:13.619
So I went searching.

24
00:01:13.619 --> 00:01:15.719
"Moiré shipping light."
"Moiré boat light."

25
00:01:15.719 --> 00:01:18.770
And after a half hour or so, I'd found a couple
of others around the UK,

26
00:01:18.770 --> 00:01:20.840
placed at the entrances to locks and marinas,

27
00:01:20.840 --> 00:01:24.570
or at the end of dredged channels,
so that people steering a boat

28
00:01:24.570 --> 00:01:27.540
know exactly which way to go
to avoid the sides.

29
00:01:27.540 --> 00:01:30.299
One guide for mariners called it
an "Inogen light"

30
00:01:30.299 --> 00:01:33.210
but that just led me to a medical company,
nothing else.

31
00:01:33.210 --> 00:01:34.210
And that was it.

32
00:01:34.210 --> 00:01:36.710
It looked like a bit of weird maritime history

33
00:01:36.710 --> 00:01:40.750
that had been a brief fad and then died out,
leaving no trace.

34
00:01:40.750 --> 00:01:43.619
A beautiful idea that the world had ignored.

35
00:01:43.619 --> 00:01:47.030
I considered starting a new series of videos
called "I Don’t Know"

36
00:01:47.030 --> 00:01:50.729
just to see if anyone knew more about it,
because it's genius

37
00:01:50.729 --> 00:01:53.429
and, yeah, I wanted to understand it.

38
00:01:53.429 --> 00:01:56.590
So much that my brain wasn't quite done,
I kept coming back, I kept searching.

39
00:01:56.590 --> 00:01:59.289
And eventually, I started looking through
patent databases.

40
00:01:59.289 --> 00:02:01.359
And after a few minutes, I found it.

41
00:02:01.359 --> 00:02:06.789
It was patented by Lars Bergkvist and
Ivan Forsen, from Sweden, in the late 1970s.

42
00:02:06.789 --> 00:02:09.840
They'd invented several things to do with
moiré patterns, between them.

43
00:02:09.840 --> 00:02:12.890
And though there are
a few more patents after the first,

44
00:02:12.890 --> 00:02:16.810
refining the idea or making it work
in two dimensions with circles,

45
00:02:16.810 --> 00:02:18.220
the trail ended there.

46
00:02:18.220 --> 00:02:21.880
I tried to track Lars or Ivan down,
and couldn't find any trace.

47
00:02:21.880 --> 00:02:24.890
The only thing I had was an address from about
forty years ago.

48
00:02:24.890 --> 00:02:26.440
And in Sweden.

49
00:02:26.440 --> 00:02:30.490
And then one little clue, spotted just out
the corner of my eye, unlocked everything.

50
00:02:30.490 --> 00:02:33.180
Yes, this was patented by Bergkvist and Forsen,

51
00:02:33.180 --> 00:02:36.840
but the patent was then assigned to a company
called Inogon.

52
00:02:36.840 --> 00:02:40.190
Not Inogen -- that was a typo,
or a corruption of the name over time.

53
00:02:40.190 --> 00:02:41.190
Inogon.

54
00:02:41.190 --> 00:02:44.880
This is known as an Inogon leading mark, or
just an Inogon light.

55
00:02:44.880 --> 00:02:48.480
And once you know that, once you name it,
you can search for it.

56
00:02:48.480 --> 00:02:52.130
You can find the US military analysis from
1986 testing that it works.

57
00:02:52.130 --> 00:02:54.680
The variations that were made for getting
an aircraft

58
00:02:54.680 --> 00:02:56.910
into the right place parking in a stand.

59
00:02:56.910 --> 00:03:00.150
The Swedish company called FMT
that now makes them,

60
00:03:00.150 --> 00:03:04.350
or did until recently, because they've just
removed it from their web site.

61
00:03:04.350 --> 00:03:07.590
Once you know that this is an Inogon light,

62
00:03:07.590 --> 00:03:10.450
all the rest of the research becomes easy.

63
00:03:10.450 --> 00:03:12.230
All except one thing.

64
00:03:12.230 --> 00:03:15.450
This Inogon light isn't being used to guide
people in.

65
00:03:15.450 --> 00:03:20.310
The light follows the path of an underwater
cable where you shouldn't drop anchor.

66
00:03:20.310 --> 00:03:22.200
So the signal here is all wrong.

67
00:03:22.200 --> 00:03:23.730
You don't want to follow these arrows,

68
00:03:23.730 --> 00:03:27.680
you're required to stay away from them unless
you're passing straight through.

69
00:03:27.680 --> 00:03:30.980
It's a really weird use
for a very expensive light.

70
00:03:30.980 --> 00:03:33.690
So why is it here?

71
00:03:33.690 --> 00:03:35.170
I don’t know.

72
00:03:35.170 --> 00:03:39.110
But if anyone out there does know, for sure,
with evidence...

73
00:03:39.110 --> 00:03:40.920
do get in touch.