June 9, 2022 • 39 mins
The original discoverers of the Polynesian Islands traversed a vast ocean, bringing civilization to islands untouched by human activity. How did they do it? In this classic Stuff to Blow Your Mind two-parter, Robert and Joe discuss the sheer scale of the Pacific Ocean and environmental navigation. (originally published 7/8/2021)
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:05):
Hey you welcome to Stuff to Blow Your Mind. This
is Robert Lamb and this is Joe McCormick, and today
we have an episode from the vault for you. This
is part two of our series on Pacific Island navigation.
This episode originally aired July. Let's dive right in Welcome
(00:25):
to Stuff to Blow Your Mind production of My Heart Radio. Hey,
welcome to Stuff to Blow Your Mind. My name is
Robert Lamb and I'm Joe McCormick, and we're back with
part two. In the last episode, we talked about the settlement,
the original colonization of the Pacific Islands, and today we're
(00:48):
back to talk about some documentation of the amazing navigation
techniques used by the master navigators of various Pacific islands.
And I'm really excited to talk about this stuff today
because I've been reading this big, very important book on
the subject that was published in nineteen seventy two by
(01:09):
an author named David Lewis, called We the Navigators that
involves extensive interviews with and then direct sailing and firsthand
observation of the navigation techniques of master navigators from the
Pacific Islands. For example, a man named Tevak of the
Santa Cruz Reef Islands and a man named hip Or
of Poula Watt in the Carolines. And today we're gonna
(01:32):
be talking about some of these specific navigation techniques. Yeah,
and again these are the techniques of environmental navigation, so
navigation at sea on the open sea, conducted without instruments.
And so I mean that's ultimately the really amazing part
of this. But then at the same same time, I
want to stress something we've mentioned in the first episode
(01:53):
that this is also not based in sort of a
gut instinct, a kind of well I've been at sea enough,
I kind of know what I'm doing. No, this is
a this is a science. This is this is these
are techniques that would have that were passed down from
generation to generation, from skilled individual to two skilled individual.
And uh and so you know, we see this continued
(02:14):
on in oral traditions, but then also we've seen them recorded,
especially in the last few decades. Uh, that there's been
a resurgence of interest in this um an effort to
to make sure that these traditions and techniques survived and
then also to use them to understand the history of
(02:36):
the colonization of these islands by ancient humans, right. And
one of the points that Lewis argues in his book
is that the colonization of the islands of the Pacific
was not driven entirely by random drift, say, people getting
blown off course by a storm or getting lost and
then happening upon a new island. That that Instead, he
(02:57):
argues that a lot of these islands were probably discovered
by deliberate exploratory probes. Right, So let's get into some
of the techniques. Then We're going to start with what
may seem the most obvious, and that is the stars.
There are a lot of amazing techniques to talk about,
but this is by far the most important one. Yes,
So Pacific islanders, uh, specifically, the trained navigators, they did
(03:22):
use the stars. The train navigator knew the positions of
important stars and their relationship to islands by heart. They
knew how the pattern of the stars changed depending on
where you went and what time of the year it was.
And they could also use the stars to determine latitude,
so that's her north south positioning. They could roughly determine
(03:43):
where they were in relation to the equator based on
the height of polaris or the southern cross above the horizon,
which they would measure, again not using instruments, but using
the human hand. Yes, or sometimes I think also maybe uh,
parts of the boat could be used to sort of
orient with the stars on the horizon. So if you're
(04:06):
unfamiliar with this kind of technique, as obviously most of
us are as I am, the mind is immediately boggled.
Right you think, Okay, how would I use the stars
to find I don't know, a city or something like that. Uh,
you don't. You wouldn't even know where to start. But
once you know what to look for, this actually becomes
an extremely reliable method. Uh, And specifically the really important
(04:28):
guide stars here are constellations that are low in the
sky around the point where they are either rising or setting,
and can be easily associated with a particular heading toward
the horizon. So you're steering your boat and you're observing
the stars right around the horizon. So these would be
either stars and star constellations that have recently risen or
(04:52):
are about to set, depending on which direction east west
you're heading. So if you have a particular destination in mind,
and you know you're starting position, you can associate your
destination with a particular guide star, or what a guide
star would actually mean is a series of stars and
star constellations that will move move vertically up and down
(05:16):
across the sky as the night goes on. But they
might be identified by say the first star you would
see in the sequence, as as the guide star, and
then the train of subsequent stars that would move up
and down as the night goes on. But that is
associated with a particular island. Now, of course, it gets
much more complicated than that, because, for one thing, you
(05:36):
have to take into account position and geography. Because while
a star can help give you a heading toward a
known island that's associated with it would only necessarily be
associated with the island you're heading for from a particular direction. Right,
So if you're heading from east to west, the island
(05:56):
you're looking for is under a certain star, but if
you're heading from north to the same island, that island
would be under a different star. Right. So the stars
help you get an orientation, but you have to know
the relationships between a sort of mental map of islands
in your head and how shifting the starting point of
the journey will shift, what star path will lead you
(06:19):
to your island destination. But it gets even more complicated
than that, because, of course, as we mentioned, the stars
don't stay still throughout the night. The earth is rotating,
so the fixed stars rise and set across the sky
over the course of a night. And as the stars
rise higher or set below the horizon, they become less
useful or not useful at all for navigating without equipment
(06:42):
and charts, not just because say, they're higher as they're
rising up, but also because they tend to rise at
an angle, so they won't stay right where they're supposed
to be on the horizon. What you want is a
reference star that is either just rising if you're heading east,
or is just about to set if your head west. Um,
So what do you do there? Well, what you would
(07:03):
tend to do is cycle through new sets of rising
or falling guide stars that you know will keep you
pointed in the right direction. And Lewis writes about this
that on average you won't need more than about ten
guide stars to sail through an entire night, given the
amount of time that each star is usually pretty close
to the horizon, close enough to be usable. So you
(07:25):
can almost imagine kind of a I don't know, like
those like stock ticker strips. You know, the old one
is like a strip of stars that are peeling up
over the horizon all night long, and each one, you know,
is the next one in the set that is still
oriented with the top star in that strip that will
keep you going in the direction you need to go.
But stop and think about, like how much memorization this requires,
(07:48):
Like how much you need to know about what the
stars look like, what their orientations are, and their relationships
to the islands you need to get to depending on
where you're starting point is So the amount of now
vigational lore that needs to be committed to memory and
the amount of detail in it is is absolutely astounding.
I mean, it reminds me a little. These are not
(08:08):
directly comparable at all, but it reminds me a little
of how in or was it Mark Twain's life on
the Mississippi talking about how an experienced riverboat pilot would
need to know by heart the entire river, like all
the various details of its its twist and binds, its depth, etcetera,
and everything that went into knowing it. Which, um, yeah,
from what I've read, you can you can basically take
(08:31):
that and apply it to to any kind of nautical setting.
And certainly this one is well like you would need
to to know by heart the environment through which you
would be uh sailing, the environment of the waters, but
also the environment of the stars above. Yeah. And it
seems that while I don't know, while the mental memorization
(08:51):
of physical surroundings on land, including like trees and changes
in terrain and rocks and landmarks and stuff like that,
it maybe this is just my land lubber bias, but
it it seems like that kind of thing probably comes
more intuitively. It's more just sort of like a biological
default to recognize landmarks like plants and rocks and stuff
like that. Then it would be to memorize the stars
(09:15):
as your landmarks for guidance. Yeah, yeah, I think you're right.
I mean, it almost feels like saving through through space. Uh,
though of course there's gonna be plenty concerning the water
itself and uh and uh and other environmental cues that
will get to But but certainly at this point in
the in the podcast, it's easy to to almost think
of these as space voyages because of the degree of
(09:38):
focus that must be placed on the stars, right, and
so experienced specific navigators can use these rising and setting
guide stars to form this extremely accurate mental compass. Lewis
gives one example of one of his voyages with the
navigator TVAK, and he says, quote, by these obliquely sinking stars,
he was able to inform me that during the evening
(10:01):
that the wind had backed from southeast to south southeast.
I seriously doubted the accuracy of his observation until Canopus,
topping the horizon on a bearing of a hundred and
forty three degrees exactly in line with our stern, confirmed
that we were in fact dead on course and that
the wind had changed. Now, there's another variation on the
(10:22):
idea of guide stars for navigation that is known as
the sidereal compass. That is basically like a view of
the night sky that identifies particular rising or setting stars
with points on an imagined compass. Again, this is not
a piece of equipment and external tool. This is a
compass in the brain that has a picture a mental
(10:44):
map of the stars and how the stars along the
horizon will give you information about north, southeast, and west. Now,
these are the basic primary methods of navigation by stars,
but obviously in practice, it's a lot more complicated, so
a few examples. Of course, there is a lot of
adjusting the course to compensate for variations in currents and winds,
(11:06):
and to be adaptable for for celestial orientation markers when
part of the sky is obscured, for example, by clouds,
and I'll mention more about that in a minute. There's
another thing that's a complication with the use of guide
stars for navigation, which is the seasonality of guide stars. Now,
of course, the availability of guide stars varies with the seasons,
(11:27):
because the sidereal day is actually twenty three hours and
fifty six minutes long, not twenty four hours. So each
star rises and sets four minutes earlier each night. And
as you can imagine, as this builds up over time,
you're actually going to be having different star maps available
to you as the year goes on. So in illustrating this,
(11:51):
Lewis writes that quote Tevak told me that the sailing
season in the Santa Cruz group lasted all year round,
and that there were appropriate steering stars for each time
of year. Similarly, when two two indicated the stars for
the Nomuka Tonga Tapoo passage, he stressed that the ones
he was showing me were usable only up to about September,
(12:14):
after which new stars and sailing directions had to be used.
So not only do you have to understand this whole
star map and its relationship to the island geography, but
also if you if you're sailing across different seasons, you
have to have the seasonal backups in mind as well.
Then there's even more to to take into account. One thing,
for example, is wind and leeway, So experience navigators will
(12:38):
have a mental map to reach their destination that must
include compensation for leeway, you know, the sideward drift of
a boat as as is blown sort of off course
by wind. So if the navigator knows that the destination
is under a particular star, but there is a known
and relatively dependable amount of southerly drift on the journey
(12:59):
do to prevailing winds and currents, they actually have to
aim a certain amount north of the guide star. Yeah,
and that's just for permanent drifts. There's also sort of
more ad hoc compensation that has to take place along
the way as well. But one of the big things
that that really struck me about this was how how
much it inverts the logic of nighttime navigation versus daytime navigation.
(13:24):
You know, uh, like, how how would you think, what
do you think would be the best time to try
to get somewhere. Obviously you would probably think it's in
the day right when you can see where you need
to go. But it is much easier to use the
highly dependable celestial navigation techniques of of the Pacific Islander
navigation lore at night than it is in the daytime.
(13:44):
There there's still tools they use in the daytime, and
I'll talk about those in a minute. Um, But even
when the stars are largely obscured by clouds and experience,
navigator can usually use some stars in the sky to
orient and to get onto the correct bearing, for example,
by noting which stars might lie it's a nine d
degrees to the course, etcetera. Yeah, I mean it almost
(14:06):
sounds like you would you would probably want to leave
the shore, you know, around dusk, um, and uh, and
then once and then hopefully you're you're out to sea
by the time the stars have come out. Right. Well,
there's actually there's a good bit of thought about when
are the best times to arrive and depart. So they
(14:28):
talked about Yeah, I think it's usually customary to leave
during the daytime. And one of the main reasons it's
important to leave during the daytime is not only that
people can be notified and you can say prepare things
to take along with you that same day, like fresh food,
and you can say your farewells to people during the daytime,
but you can also look back at the island you're
(14:49):
leaving from to get back bearings, right, so you can
make use of the land if your navigation for as
long as it's feasible, right. And it's also usually can
cosidered important to arrive at your destination during the daytime
because one of the great perils actually of Pacific navigation
is accidentally missing your target in the dark. If you
(15:13):
sail past the island in the dark and you don't
realize you've done it, that can be uh that that
could be a death sentence. So it's kind of interesting
while you're out on the open ocean, navigating at night
is ideal. That's you know, where you get these accurate
guide stars. But I think it's often considered good to
leave the island during the daytime and to arrive at
(15:34):
your destination during the daytime. And sometimes uh. And there
might be some exceptions to that, but those seem to
be some general principles that were observed at least that
Lewis mentioned and uh. And so that would require very
careful timing of the journey, right, Like you need to
know pretty much exactly how long it's going to take,
how many days, so that you can time it out
like that. And just as one example about the dangers
(15:56):
of missing an island at night, uh, the Lewis talk
about at least one of the navigators he worked with
having a practice of when you're getting close to the
island and it's really dark out, sometimes they would just
stop sailing. They would slow down. They would uh it's
called heaving to you know, they would heave to to
slow the progress of the boat, just to be super
(16:17):
careful that they didn't accidentally, say, sail between two islands
unnoticed in the middle of the night. But while the
nighttime star navigation is the most accurate thing to use,
there are clues you can use for navigation in the
daytime as well. For example, you can use the sun.
It's more difficult to use the sun, but it can
be done. Uh. And it's more difficult for a number
(16:38):
of reasons. First of all, there's only one of it,
and its position can vary a lot over the seasons. Right,
Unlike the stars, the relative position of the Sun on
the horizon of Earth has a lot more variability. But
even with the seasonal variability of the Sun's position, you
can still use it to navigate by pairing it with
external reference to the stars. And this was one of
(17:01):
the many moments in this book. It gave me that like, oh,
of course kind of feeling, and this was one of them.
So uh So, Lewis writes at one point about another
scholar who had been writing about Pacific navigation uh named
acre Blom. He says, quote acre Blom surprisingly asserts that
to achieve a satisfactory degree of accuracy when checking the
course by means of the bearing of the rising or
(17:22):
setting sun, the Polynesian navigator must necessarily have had access
to some form of memorized table of the changes in
the sun's asimuth. So it's you know, changes in rising
and setting patterns over the seasons. But contrary to that,
Lewis says, all the navigator actually needs, of course, are
his eyes and a knowledge of the stars. The sun
(17:43):
star comparison could be made twice in each day if
one were so minded. So when the sun is rising
or setting, you can check its orientation with respect to
the stars that appear, you know, before or after it,
and then you can basically know where on the horizon
it is rising or setting at this time of er. Wow. Yeah.
(18:08):
Now there are other methods of maintaining course setting during
the daytime that are again more difficult than the nighttime,
but still possible. And another method that I thought was
really interesting was steering by ocean swells. And there are
actually two different uses here. Um, So there's one thing,
which is navigation by swells in the open water. So
(18:28):
if you're out you know no side of land anywhere nearby,
you can use ocean swells to help you do direction finding,
just like you would use the sun or the stars.
But in addition to that, using the swells is actually
a land finding technique. It changes in how the ocean
swells are affected by nearby land masses can be used
to locate islands that are nearby, and this is something
(18:50):
we'll probably talk about more in the next part of
this of this series. But what does it mean to
steer by swells in the daytime. Well swells are permanent
wave patterns with specific cardinal origin points, which are associated
not with waves kicked up by transient weather, but with
strong and persistent wind patterns associated with specific permanent weather systems,
(19:14):
for example, the trade winds or what or what A
Louis calls the Southern Ocean belt of strong Westerly's. Yeah,
and I think we can sort of loosely imagine like
a recreation of a basic form of this, you know,
some sort of a model or a simulation. If you
had a body of water and you had say a
fan or something creating some sort of you know, disturbance
(19:38):
across the surface, and it it was regular, what would
happen if you then dropped some islands in there? It
could disrupt the waves, especially in if we were talking
in in the actual ocean, in the form of long
ocean waves as they bend around land masses, and and
this wave disruption can be identified by a skilled eye
(19:59):
enable them to detect land hundreds of kilometers wave and
which is is pretty amazing, right, And so that's the
kind that would be used specifically for the land finding, right,
But you can also use the c swells, like you
would use the stars to get directional orientation to know
which direction is north southeast or west without a compass,
because if you know basically what direction a c swell
(20:23):
that is permanent and reliable comes from, you can detect
that swell and then no, okay, that way is south southeast. Right.
So so now we have not only the stars above,
but also uh the wave patterns the CEA swells as well. Right,
So these permanent weather patterns, they originate in a fairly
consistent direction from your location. Now, part of the ignorant
(20:47):
land dweller in me is just incredulous here, right, Like
when I'm out in a boat on the ocean, waves
seem utterly random to me. I could not I could
not identify that waves are coming from a particular direction.
And you know, but they're well, unless it's coming from
a ski do right then you write motor boat that's coming.
By then it's pretty clear what's creating the distraction. That's
a good point. But you know, just the general choppy
(21:09):
wave patterns of the ocean, I wouldn't have any idea
what to do. But if you are trained in knowing
what to look for, you actually can identify particular wave
patterns or swell patterns. Lewis actually makes a distinction between
waves and swells um but but they're not just random.
The system of orientation based on swells is not as
(21:31):
reliable as the stars, but it's still pretty reliable. So
the question would be, well, how do you detect them?
One interesting fact is that the navigators Lewis learned from
seemed to consult the swells based on feeling them in
the body more so than looking at them, which means
that they can be used to steer not only in
(21:52):
the daytime, but on overcast nights. So when the stars
are completely hidden that's your main orientation tool gone, and
there's no light to see, you could still potentially feel
the directional swells and get an orientation based on that. Wow,
that's interesting and it makes perfect sense. So how do
you feel swells? Well, there's a part in Lewis's book
(22:14):
where he talks about this. He says, quote T. K
told me he would sometimes retire to the hut on
his canoes out rigger platform, where he could lie down
and without distraction, more readily direct the helmsman onto the
proper course. By analyzing the role and pitch of the
vessel as it cork screwed over the waves. In distinguishing swells,
(22:36):
he stressed, you have to wait patiently until the one
you want has a spell of being prominent and discernible.
So there is a lot of noise in the waves, right,
So there's a lot of conflicting, you know, wave wave
action coming in different directions. But there's a certain pattern
you can recognize from a known swell, And once there's
(22:56):
a there's the right kind of timing in the wave
action for you to IDENTI find the pattern of that
known directional swell, you can orient based on that, and
this would be again done by feeling it in the
body and feeling the direction of the rolling of the boat.
So when you think about how a boat moves in
the waves, it can pitch, it can move up and down,
(23:17):
forward to back, and it can roll from side to side,
and the interaction of pitch and roll will tell you
something about the direction that the swell is coming from.
Right now, in saying that this type of navigation method
is more reliable than it sounds, I also don't want
to overstate or understate the difficulty of detecting it right
(23:38):
that there is a lot of noisy way of action
going on in the ocean, so somebody has to be
really experienced and know what it is they're feeling for
in order to feel it. And I just want to
read one section of Lewis talking about attempting to understand
what's going on with the navigation based on swells. Uh
He writes, quote the course toward Tomaco was east northeat
(24:00):
directly into the C swell that came from the same
direction that it was only present or at any rate detectable.
Occasionally at such times it could be picked out by I,
and as the ship rowed up and over it, meaning
pitched without any role at all, except when the steep
northerly wind wave happened to coincide when the boat, the
(24:21):
Spiorn was rolled to starboard at the same moment as
she was pitching over the head on C swell. In
those long intervals where the C swell was absent, the
wind wave rolled us to starboard about once every five
seconds without there being any pitching component. I could feel
little effect from the southeast or northwest swells. After nightfall,
(24:43):
we steered by the stars, the swells remaining unchanged except
that the wind wave declined. So that's about like trying
to understand that they're different. In fact, there are multiple
swells at any given time, probably hitting you from different directions,
and so the experience navigator is looking or a particular
type of swell. You know that you could actually make
(25:04):
the same journey potentially and look for different swells to
steer you in aid of it. You just have to
know which ones you're feeling for. And that goes back
to the example you mentioned earlier about just like like
setting there or laying there on the boat and just
waiting to to feel the one you're looking for. It's
not just okay, the waves you're hitting me, I got
(25:25):
the pattern. No, you're looking for the specific pattern amid
the noise or amid the waves right when there may
be multiple patterns coming at you at the same time.
You're just trying to pick the right one out, get
the timing right to understand, yes, this is it. But
as you were talking about earlier, I think it's important
to remember and again, well we'll get more into this
in the next episode. The ability to detect and measure
(25:46):
swells in their direction of origin is not useful just
in steering on the open ocean, but it's also one
of the techniques for understanding when land is near. Now,
there are a couple of other things that are really
interesting about navig aiding on the open ocean. There's one
more orientation technique that is even less reliable than the others,
but it is sometimes still used as a backup. That's
(26:08):
known as the wind compass. So it's it's basically operating
on the presence of known wind patterns to give you
indications about about directionality. So you might, for example, use
the aid of a tool here, an external tool like
a pennant, the you know, kind of flag object that
would allow you to determine patterns of winds and where
(26:29):
they come from. And if you know that there are
certain dominant patterns of winds, you can kind of use
that to give you another data point in orienting your
boat in the right direction. Now, there's a whole other
world of ad hoc adjustment that needs to take place
on top of everything we've already been talking about. You know,
basically everything we've been talking about is getting the correct bearing,
(26:52):
knowing you're going in the right direction towards your target
island based on your starting point. But of course in
sailing you can always just sail in a straight line.
Right winds and ocean currents will gradually shift you off
course and you have to understand how that's happening and
compensate for it. Which again this is one of those
things where I just like react to that, thinking like
(27:15):
it seems impossible, how could you do it? But but
they have methods that they can do it. And there
are a lot of methods here, but for example, one
that I really liked, Lewis discusses on the first stage
of one journey with hip Hoor, departing from pula Wat,
hip Hoor would keep track of back bearings on the
island that they were leaving to see how the current
(27:38):
was affecting their heading. So you have the reference point
of the island, landmarks the island you're leaving, and then
you can see from your heading as you're leaving the
island how strong the current is at the moment. And then,
to to read from Louis here quote if said hip
Hoor it turned out on further observation to be weak,
(27:59):
we would head towards It's the point where vegas set,
which is about at three hundred and nine degrees if strong,
as proved to be the case towards the setting point
of the pl A D s at about two hundred
and eighty five degrees. Thus there were at least two
distinct star courses traditionally laid down for this passage, and
probably four to allow for strong and weak south flowing currents.
(28:21):
This was a north flowing current. So not only do
you need to know the right headings for uh, for
the island you need to get to under you know,
basically like neutral conditions, you also have to know what
headings you would use if the current is a certain
strength in a certain direction and the corresponding guide stars
(28:41):
of course, um. But so if the wind or current
is moving you laterally off course while steering in the
open ocean, and so you don't have like, you know,
back bearings like an island to refer to. How would
you even know it? How do you know how far
off course you're getting blown by the wind. This was
another moment where the technique was revealed and was like, oh,
of course, I thought this method was ingenious. Some of
(29:04):
the navigators here would look at the wake left behind
by the boat. So if if leeway I mean, you know,
wind the blowing the boat sideways in addition to forward.
If leeway is affecting your course, one way to judge
this is by looking at the degree of the angle
between the straight line you're attempting to steer on. So
(29:26):
you can imagine a straight line going from the stern
to the bow of the boat, you know, and just
going off towards the horizon in every direction. Look at
the angle between that line and the trail of wake
left behind you. This might be kind of hard to
visualize without a without a picture, so I'm sorry, but Rob,
I've got a picture for you to look at. Here
you can see that there's actually an angle of difference
(29:49):
in between the wake behind the boat as you're getting
blown off course and the straight line that you are
attempting to steer on. Yeah, you can imagine it is
looking back and saying, not a straight wake behind you
going back to you know, to just directly behind you,
as if it is a line drawn from the rear
of the vessel, but something that is diagonal because because
(30:12):
of the way the wind is blowing the vessel from
the side right. So by seeing that angle and how
large it is, a master navigator is able to correct
for the amount of leeway that they're being blown off course.
Now there's a huge thing that we haven't gotten into
(30:34):
in detail yet here, but a big section of Lewis's
book is about the Pacific navigation forms of dead reckoning,
and dead reckoning is estimating the position of your boat
without reference to any new markers around you, but rather
by knowing your past position and estimating how far you
(30:54):
have traveled from there and in what direction. So this
is crucial to keeping track of your journey. But this
is a different thing because it's not giving you new
information from your surroundings. It's rather a sort of keeping
track of your position on a mental map by just
using the information already in your possession. And one mental
(31:14):
tool that seems to help with this process and Pacific
navigation has been referred to as attack. Again, this is
not a means of acquiring new information from the environment,
but rather a visualization or a mental reference system for
understanding one's place in relation to other things. Unfortunately, this
is yet another concept that is kind of hard to
(31:36):
explain without visual aids. But Rob, I've got a visual
aid for you to look at here, and I will
do my best to try to explain it. Basically, it
hinges on having this mastery of relationships between stars, vantage points,
and various geographical locations, specifically islands on in the nearby surroundings.
(31:56):
So as a point of analogy, imagine that you want
to travel between New York in Chicago by stars. One
way that I can help understand where I am along
my journey is if I have a third reference point
in mind. So let's say Atlanta. So I know that
I start in New York, and when I start in
(32:16):
New York, I know from where I am, Atlanta is
going to be under Star A from my point of view.
So if I wanted to travel to Atlanta, I would
take my beer, I would head towards Star A on
the horizon. But by the time I reached Chicago, now,
because I'm at a different vantage point, Atlanta is underneath
Star C from my point of view, and there's a
(32:38):
midpoint in between Chicago and New York where Atlanta, from
my vantage point is underneath Star B. So the whole
time I never see Atlanta. But this mental reference system
allows me to break my journey into recognizable segments where
I keep track of each time the third reference island
or in my analogy, Atlanta has moved under a new
(33:02):
star from my point of view. Does that make sense? Yeah,
I think so. And this this visual reference helps a bed. Yeah,
I'm sorry you folks at home can't see it, but uh,
actually you know if you do, if you do just
a Google search for etach reference points, I don't think
you will find the exact um illustration that I'm looking at,
(33:23):
but you'll see some that are similar to They give
you an idea of what we're talking about. It's e
T A K. Yeah, though it's complicated by the fact
that this appears also to be the name of a
like a car navigation system, uh software. So if you
if you Google attack islands there you'll see the right illustrations. Yeah, yeah,
(33:45):
that'll cut out some of the car stuff. But I
think this system is is also really interesting because it
I think it still is important to think of it
as a useful tool for navigation, even though it provides
no additional information to the navigator. Instead, what it is
is it seems to be that it's useful as a
system for mentally keeping track of the information you already have,
(34:10):
for knowing how far you've come, where you are, and
how far you have left to go. Uh, which is
interesting because I mean, obviously that's an important part of
of any travel, right, is sort of visualizing the whole
of your journey in ways they're not immediately apparent to
your senses. Yeah, and I guess as in modern travelers
with modern instruments, being at sea or on land, Yeah,
(34:33):
we're still engaging in some level of that. We still
have some level of a mental map, but we have
these other tools that make our mental map less important.
Maybe sometimes the mental map is even incorrect. Like you know,
if you're if you're relying heavily on a GPS device
to drive you from one point to the other. I
guess you could theoretically not know if you're really driving
(34:56):
north or west or south or what have you, as
long as the system got you there. But in this case,
the mental map is everything. The Milton in the mental
map has to be carefully cultivated using uh knowledge of
all of these environmental cues, these different systems. Uh. It's
it's really quite quite amazing. Uh it's uh yeah, it's
(35:18):
it's it's something else. So when you're driving somewhere new
that you've never been before with the aid of a GPS,
you know, like a map, SAP on a phone or something.
Can Can you just plug it in and go? Or
do you, like me strongly prefer to look at the
whole route first. Um, I tend to just go the
(35:39):
same way I do recipes for meals. It's just I
just trust that. I mean, I look and make sure
I have what I need. In the same case, I'll
look at my gas tank and make sure I have
enough gas to get where I'm going. I'll see how
much how long it says it's gonna take for me
to get there. But then I'll just go I'll just
start cooking, or I'll or I'll just start driving and
(35:59):
trust that I will get there and I'll figure out
on the way of there any snakes. This must be
differences in personality type somehow, I guess I'm I'm more
annoying about this or something. I really don't like having
to navigate based on just a moment to moment directions
on an app without seeing the entire route first. I
like to look at the whole map, see what the
(36:21):
steps are, see how far it is, see like see
it visually represented. That really matters to me for some reason.
I mean, I might glance at it if if I
know there's going to be some weird exit, if it
says that, oh, I'm getting off at this exit, and
normally I don't do that. I'm kind of curious what
route I'm taking then, But otherwise I just go, well,
you know. The weird thing is, I think one reason
(36:42):
I do that, it's not like it usually gives me
important information that I actually need in addition to whatever
the step by step instructions in real time are. Instead,
I feel like it's something closer to the attack system,
where I just want to be able to visualize in
this app stract way the whole of the journey and
sort of imagine where I am along the journey at
(37:05):
various points. M yeah, but I feel like I'm going
to do that anyway as I drive, Like there's kind
of a perhaps a less accurate version of that that's
going to be going on in my head. But it
says it's as accurate as it needs to be. Yeah,
Like if the GPS satellites were to suddenly get taken
out by aliens or something, um, you know, I could
I get backtrack or even if it's if I've driven
(37:28):
this particular route before, I can probably remember the rest
of the way. Um, But otherwise I'm good. Well, I
wonder if we should call part two there and then
come back in part three to talk about one of
the next really interesting things, which is all of this
has been mostly about navigation, direction finding and navigation, especially
on the open sea, but a whole other part of
(37:48):
this science of navigation is land finding. When you're getting
close to an island, how do you know that and
how do you find it? And so let's save that
for part three. Yeah, part three, we will we will
make landfall or try to make landfall appropriately. All right.
In the meantime, if you would like to check out
other episodes of Stuff to Blow Your Mind, you know
where you can find them in the Stuff to Blow
(38:10):
your Mind podcast feed. We have core episodes of Stuff
to Blow Your Mind on Tuesdays and Thursdays. On Monday's
we do a little listener mail. On Wednesdays we do
short form episode we're calling it the Artifact, and then
on Friday's we do Weird How Cinema. That's our time
to set aside most of the science and the culture
and just talk about a weird emotion picture and then
(38:31):
we have reruns on the weekend. Huge thanks as always
to our excellent audio producer Seth Nicholas Johnson. If you
would look to get in touch with us with feedback
on this episode or any other, to suggest a topic
for the future, or just to say hello, you can
email us at contact. That's Stuff to Blow your Mind
dot com Stuff to Blow your Mind. It's production of
(38:57):
I Heart Radio. For more podcasts, my heart Radio. This
is the i heart Radio app, Apple Podcasts, or wherever
you're listening to your favorite shows.
Hey you welcome to Stuff to Blow Your Mind. This
is Robert Lamb and this is Joe McCormick, and today
we have an episode from the vault for you. This
is part two of our series on Pacific Island navigation.
This episode originally aired July. Let's dive right in Welcome
(00:25):
to Stuff to Blow Your Mind production of My Heart Radio. Hey,
welcome to Stuff to Blow Your Mind. My name is
Robert Lamb and I'm Joe McCormick, and we're back with
part two. In the last episode, we talked about the settlement,
the original colonization of the Pacific Islands, and today we're
(00:48):
back to talk about some documentation of the amazing navigation
techniques used by the master navigators of various Pacific islands.
And I'm really excited to talk about this stuff today
because I've been reading this big, very important book on
the subject that was published in nineteen seventy two by
(01:09):
an author named David Lewis, called We the Navigators that
involves extensive interviews with and then direct sailing and firsthand
observation of the navigation techniques of master navigators from the
Pacific Islands. For example, a man named Tevak of the
Santa Cruz Reef Islands and a man named hip Or
of Poula Watt in the Carolines. And today we're gonna
(01:32):
be talking about some of these specific navigation techniques. Yeah,
and again these are the techniques of environmental navigation, so
navigation at sea on the open sea, conducted without instruments.
And so I mean that's ultimately the really amazing part
of this. But then at the same same time, I
want to stress something we've mentioned in the first episode
(01:53):
that this is also not based in sort of a
gut instinct, a kind of well I've been at sea enough,
I kind of know what I'm doing. No, this is
a this is a science. This is this is these
are techniques that would have that were passed down from
generation to generation, from skilled individual to two skilled individual.
And uh and so you know, we see this continued
(02:14):
on in oral traditions, but then also we've seen them recorded,
especially in the last few decades. Uh, that there's been
a resurgence of interest in this um an effort to
to make sure that these traditions and techniques survived and
then also to use them to understand the history of
(02:36):
the colonization of these islands by ancient humans, right. And
one of the points that Lewis argues in his book
is that the colonization of the islands of the Pacific
was not driven entirely by random drift, say, people getting
blown off course by a storm or getting lost and
then happening upon a new island. That that Instead, he
(02:57):
argues that a lot of these islands were probably discovered
by deliberate exploratory probes. Right, So let's get into some
of the techniques. Then We're going to start with what
may seem the most obvious, and that is the stars.
There are a lot of amazing techniques to talk about,
but this is by far the most important one. Yes,
So Pacific islanders, uh, specifically, the trained navigators, they did
(03:22):
use the stars. The train navigator knew the positions of
important stars and their relationship to islands by heart. They
knew how the pattern of the stars changed depending on
where you went and what time of the year it was.
And they could also use the stars to determine latitude,
so that's her north south positioning. They could roughly determine
(03:43):
where they were in relation to the equator based on
the height of polaris or the southern cross above the horizon,
which they would measure, again not using instruments, but using
the human hand. Yes, or sometimes I think also maybe uh,
parts of the boat could be used to sort of
orient with the stars on the horizon. So if you're
(04:06):
unfamiliar with this kind of technique, as obviously most of
us are as I am, the mind is immediately boggled.
Right you think, Okay, how would I use the stars
to find I don't know, a city or something like that. Uh,
you don't. You wouldn't even know where to start. But
once you know what to look for, this actually becomes
an extremely reliable method. Uh, And specifically the really important
(04:28):
guide stars here are constellations that are low in the
sky around the point where they are either rising or setting,
and can be easily associated with a particular heading toward
the horizon. So you're steering your boat and you're observing
the stars right around the horizon. So these would be
either stars and star constellations that have recently risen or
(04:52):
are about to set, depending on which direction east west
you're heading. So if you have a particular destination in mind,
and you know you're starting position, you can associate your
destination with a particular guide star, or what a guide
star would actually mean is a series of stars and
star constellations that will move move vertically up and down
(05:16):
across the sky as the night goes on. But they
might be identified by say the first star you would
see in the sequence, as as the guide star, and
then the train of subsequent stars that would move up
and down as the night goes on. But that is
associated with a particular island. Now, of course, it gets
much more complicated than that, because, for one thing, you
(05:36):
have to take into account position and geography. Because while
a star can help give you a heading toward a
known island that's associated with it would only necessarily be
associated with the island you're heading for from a particular direction. Right,
So if you're heading from east to west, the island
(05:56):
you're looking for is under a certain star, but if
you're heading from north to the same island, that island
would be under a different star. Right. So the stars
help you get an orientation, but you have to know
the relationships between a sort of mental map of islands
in your head and how shifting the starting point of
the journey will shift, what star path will lead you
(06:19):
to your island destination. But it gets even more complicated
than that, because, of course, as we mentioned, the stars
don't stay still throughout the night. The earth is rotating,
so the fixed stars rise and set across the sky
over the course of a night. And as the stars
rise higher or set below the horizon, they become less
useful or not useful at all for navigating without equipment
(06:42):
and charts, not just because say, they're higher as they're
rising up, but also because they tend to rise at
an angle, so they won't stay right where they're supposed
to be on the horizon. What you want is a
reference star that is either just rising if you're heading east,
or is just about to set if your head west. Um,
So what do you do there? Well, what you would
(07:03):
tend to do is cycle through new sets of rising
or falling guide stars that you know will keep you
pointed in the right direction. And Lewis writes about this
that on average you won't need more than about ten
guide stars to sail through an entire night, given the
amount of time that each star is usually pretty close
to the horizon, close enough to be usable. So you
(07:25):
can almost imagine kind of a I don't know, like
those like stock ticker strips. You know, the old one
is like a strip of stars that are peeling up
over the horizon all night long, and each one, you know,
is the next one in the set that is still
oriented with the top star in that strip that will
keep you going in the direction you need to go.
But stop and think about, like how much memorization this requires,
(07:48):
Like how much you need to know about what the
stars look like, what their orientations are, and their relationships
to the islands you need to get to depending on
where you're starting point is So the amount of now
vigational lore that needs to be committed to memory and
the amount of detail in it is is absolutely astounding.
I mean, it reminds me a little. These are not
(08:08):
directly comparable at all, but it reminds me a little
of how in or was it Mark Twain's life on
the Mississippi talking about how an experienced riverboat pilot would
need to know by heart the entire river, like all
the various details of its its twist and binds, its depth, etcetera,
and everything that went into knowing it. Which, um, yeah,
from what I've read, you can you can basically take
(08:31):
that and apply it to to any kind of nautical setting.
And certainly this one is well like you would need
to to know by heart the environment through which you
would be uh sailing, the environment of the waters, but
also the environment of the stars above. Yeah. And it
seems that while I don't know, while the mental memorization
(08:51):
of physical surroundings on land, including like trees and changes
in terrain and rocks and landmarks and stuff like that,
it maybe this is just my land lubber bias, but
it it seems like that kind of thing probably comes
more intuitively. It's more just sort of like a biological
default to recognize landmarks like plants and rocks and stuff
like that. Then it would be to memorize the stars
(09:15):
as your landmarks for guidance. Yeah, yeah, I think you're right.
I mean, it almost feels like saving through through space. Uh,
though of course there's gonna be plenty concerning the water
itself and uh and uh and other environmental cues that
will get to But but certainly at this point in
the in the podcast, it's easy to to almost think
of these as space voyages because of the degree of
(09:38):
focus that must be placed on the stars, right, and
so experienced specific navigators can use these rising and setting
guide stars to form this extremely accurate mental compass. Lewis
gives one example of one of his voyages with the
navigator TVAK, and he says, quote, by these obliquely sinking stars,
he was able to inform me that during the evening
(10:01):
that the wind had backed from southeast to south southeast.
I seriously doubted the accuracy of his observation until Canopus,
topping the horizon on a bearing of a hundred and
forty three degrees exactly in line with our stern, confirmed
that we were in fact dead on course and that
the wind had changed. Now, there's another variation on the
(10:22):
idea of guide stars for navigation that is known as
the sidereal compass. That is basically like a view of
the night sky that identifies particular rising or setting stars
with points on an imagined compass. Again, this is not
a piece of equipment and external tool. This is a
compass in the brain that has a picture a mental
(10:44):
map of the stars and how the stars along the
horizon will give you information about north, southeast, and west. Now,
these are the basic primary methods of navigation by stars,
but obviously in practice, it's a lot more complicated, so
a few examples. Of course, there is a lot of
adjusting the course to compensate for variations in currents and winds,
(11:06):
and to be adaptable for for celestial orientation markers when
part of the sky is obscured, for example, by clouds,
and I'll mention more about that in a minute. There's
another thing that's a complication with the use of guide
stars for navigation, which is the seasonality of guide stars. Now,
of course, the availability of guide stars varies with the seasons,
(11:27):
because the sidereal day is actually twenty three hours and
fifty six minutes long, not twenty four hours. So each
star rises and sets four minutes earlier each night. And
as you can imagine, as this builds up over time,
you're actually going to be having different star maps available
to you as the year goes on. So in illustrating this,
(11:51):
Lewis writes that quote Tevak told me that the sailing
season in the Santa Cruz group lasted all year round,
and that there were appropriate steering stars for each time
of year. Similarly, when two two indicated the stars for
the Nomuka Tonga Tapoo passage, he stressed that the ones
he was showing me were usable only up to about September,
(12:14):
after which new stars and sailing directions had to be used.
So not only do you have to understand this whole
star map and its relationship to the island geography, but
also if you if you're sailing across different seasons, you
have to have the seasonal backups in mind as well.
Then there's even more to to take into account. One thing,
for example, is wind and leeway, So experience navigators will
(12:38):
have a mental map to reach their destination that must
include compensation for leeway, you know, the sideward drift of
a boat as as is blown sort of off course
by wind. So if the navigator knows that the destination
is under a particular star, but there is a known
and relatively dependable amount of southerly drift on the journey
(12:59):
do to prevailing winds and currents, they actually have to
aim a certain amount north of the guide star. Yeah,
and that's just for permanent drifts. There's also sort of
more ad hoc compensation that has to take place along
the way as well. But one of the big things
that that really struck me about this was how how
much it inverts the logic of nighttime navigation versus daytime navigation.
(13:24):
You know, uh, like, how how would you think, what
do you think would be the best time to try
to get somewhere. Obviously you would probably think it's in
the day right when you can see where you need
to go. But it is much easier to use the
highly dependable celestial navigation techniques of of the Pacific Islander
navigation lore at night than it is in the daytime.
(13:44):
There there's still tools they use in the daytime, and
I'll talk about those in a minute. Um, But even
when the stars are largely obscured by clouds and experience,
navigator can usually use some stars in the sky to
orient and to get onto the correct bearing, for example,
by noting which stars might lie it's a nine d
degrees to the course, etcetera. Yeah, I mean it almost
(14:06):
sounds like you would you would probably want to leave
the shore, you know, around dusk, um, and uh, and
then once and then hopefully you're you're out to sea
by the time the stars have come out. Right. Well,
there's actually there's a good bit of thought about when
are the best times to arrive and depart. So they
(14:28):
talked about Yeah, I think it's usually customary to leave
during the daytime. And one of the main reasons it's
important to leave during the daytime is not only that
people can be notified and you can say prepare things
to take along with you that same day, like fresh food,
and you can say your farewells to people during the daytime,
but you can also look back at the island you're
(14:49):
leaving from to get back bearings, right, so you can
make use of the land if your navigation for as
long as it's feasible, right. And it's also usually can
cosidered important to arrive at your destination during the daytime
because one of the great perils actually of Pacific navigation
is accidentally missing your target in the dark. If you
(15:13):
sail past the island in the dark and you don't
realize you've done it, that can be uh that that
could be a death sentence. So it's kind of interesting
while you're out on the open ocean, navigating at night
is ideal. That's you know, where you get these accurate
guide stars. But I think it's often considered good to
leave the island during the daytime and to arrive at
(15:34):
your destination during the daytime. And sometimes uh. And there
might be some exceptions to that, but those seem to
be some general principles that were observed at least that
Lewis mentioned and uh. And so that would require very
careful timing of the journey, right, Like you need to
know pretty much exactly how long it's going to take,
how many days, so that you can time it out
like that. And just as one example about the dangers
(15:56):
of missing an island at night, uh, the Lewis talk
about at least one of the navigators he worked with
having a practice of when you're getting close to the
island and it's really dark out, sometimes they would just
stop sailing. They would slow down. They would uh it's
called heaving to you know, they would heave to to
slow the progress of the boat, just to be super
(16:17):
careful that they didn't accidentally, say, sail between two islands
unnoticed in the middle of the night. But while the
nighttime star navigation is the most accurate thing to use,
there are clues you can use for navigation in the
daytime as well. For example, you can use the sun.
It's more difficult to use the sun, but it can
be done. Uh. And it's more difficult for a number
(16:38):
of reasons. First of all, there's only one of it,
and its position can vary a lot over the seasons. Right,
Unlike the stars, the relative position of the Sun on
the horizon of Earth has a lot more variability. But
even with the seasonal variability of the Sun's position, you
can still use it to navigate by pairing it with
external reference to the stars. And this was one of
(17:01):
the many moments in this book. It gave me that like, oh,
of course kind of feeling, and this was one of them.
So uh So, Lewis writes at one point about another
scholar who had been writing about Pacific navigation uh named
acre Blom. He says, quote acre Blom surprisingly asserts that
to achieve a satisfactory degree of accuracy when checking the
course by means of the bearing of the rising or
(17:22):
setting sun, the Polynesian navigator must necessarily have had access
to some form of memorized table of the changes in
the sun's asimuth. So it's you know, changes in rising
and setting patterns over the seasons. But contrary to that,
Lewis says, all the navigator actually needs, of course, are
his eyes and a knowledge of the stars. The sun
(17:43):
star comparison could be made twice in each day if
one were so minded. So when the sun is rising
or setting, you can check its orientation with respect to
the stars that appear, you know, before or after it,
and then you can basically know where on the horizon
it is rising or setting at this time of er. Wow. Yeah.
(18:08):
Now there are other methods of maintaining course setting during
the daytime that are again more difficult than the nighttime,
but still possible. And another method that I thought was
really interesting was steering by ocean swells. And there are
actually two different uses here. Um, So there's one thing,
which is navigation by swells in the open water. So
(18:28):
if you're out you know no side of land anywhere nearby,
you can use ocean swells to help you do direction finding,
just like you would use the sun or the stars.
But in addition to that, using the swells is actually
a land finding technique. It changes in how the ocean
swells are affected by nearby land masses can be used
to locate islands that are nearby, and this is something
(18:50):
we'll probably talk about more in the next part of
this of this series. But what does it mean to
steer by swells in the daytime. Well swells are permanent
wave patterns with specific cardinal origin points, which are associated
not with waves kicked up by transient weather, but with
strong and persistent wind patterns associated with specific permanent weather systems,
(19:14):
for example, the trade winds or what or what A
Louis calls the Southern Ocean belt of strong Westerly's. Yeah,
and I think we can sort of loosely imagine like
a recreation of a basic form of this, you know,
some sort of a model or a simulation. If you
had a body of water and you had say a
fan or something creating some sort of you know, disturbance
(19:38):
across the surface, and it it was regular, what would
happen if you then dropped some islands in there? It
could disrupt the waves, especially in if we were talking
in in the actual ocean, in the form of long
ocean waves as they bend around land masses, and and
this wave disruption can be identified by a skilled eye
(19:59):
enable them to detect land hundreds of kilometers wave and
which is is pretty amazing, right, And so that's the
kind that would be used specifically for the land finding, right,
But you can also use the c swells, like you
would use the stars to get directional orientation to know
which direction is north southeast or west without a compass,
because if you know basically what direction a c swell
(20:23):
that is permanent and reliable comes from, you can detect
that swell and then no, okay, that way is south southeast. Right.
So so now we have not only the stars above,
but also uh the wave patterns the CEA swells as well. Right,
So these permanent weather patterns, they originate in a fairly
consistent direction from your location. Now, part of the ignorant
(20:47):
land dweller in me is just incredulous here, right, Like
when I'm out in a boat on the ocean, waves
seem utterly random to me. I could not I could
not identify that waves are coming from a particular direction.
And you know, but they're well, unless it's coming from
a ski do right then you write motor boat that's coming.
By then it's pretty clear what's creating the distraction. That's
a good point. But you know, just the general choppy
(21:09):
wave patterns of the ocean, I wouldn't have any idea
what to do. But if you are trained in knowing
what to look for, you actually can identify particular wave
patterns or swell patterns. Lewis actually makes a distinction between
waves and swells um but but they're not just random.
The system of orientation based on swells is not as
(21:31):
reliable as the stars, but it's still pretty reliable. So
the question would be, well, how do you detect them?
One interesting fact is that the navigators Lewis learned from
seemed to consult the swells based on feeling them in
the body more so than looking at them, which means
that they can be used to steer not only in
(21:52):
the daytime, but on overcast nights. So when the stars
are completely hidden that's your main orientation tool gone, and
there's no light to see, you could still potentially feel
the directional swells and get an orientation based on that. Wow,
that's interesting and it makes perfect sense. So how do
you feel swells? Well, there's a part in Lewis's book
(22:14):
where he talks about this. He says, quote T. K
told me he would sometimes retire to the hut on
his canoes out rigger platform, where he could lie down
and without distraction, more readily direct the helmsman onto the
proper course. By analyzing the role and pitch of the
vessel as it cork screwed over the waves. In distinguishing swells,
(22:36):
he stressed, you have to wait patiently until the one
you want has a spell of being prominent and discernible.
So there is a lot of noise in the waves, right,
So there's a lot of conflicting, you know, wave wave
action coming in different directions. But there's a certain pattern
you can recognize from a known swell, And once there's
(22:56):
a there's the right kind of timing in the wave
action for you to IDENTI find the pattern of that
known directional swell, you can orient based on that, and
this would be again done by feeling it in the
body and feeling the direction of the rolling of the boat.
So when you think about how a boat moves in
the waves, it can pitch, it can move up and down,
(23:17):
forward to back, and it can roll from side to side,
and the interaction of pitch and roll will tell you
something about the direction that the swell is coming from.
Right now, in saying that this type of navigation method
is more reliable than it sounds, I also don't want
to overstate or understate the difficulty of detecting it right
(23:38):
that there is a lot of noisy way of action
going on in the ocean, so somebody has to be
really experienced and know what it is they're feeling for
in order to feel it. And I just want to
read one section of Lewis talking about attempting to understand
what's going on with the navigation based on swells. Uh
He writes, quote the course toward Tomaco was east northeat
(24:00):
directly into the C swell that came from the same
direction that it was only present or at any rate detectable.
Occasionally at such times it could be picked out by I,
and as the ship rowed up and over it, meaning
pitched without any role at all, except when the steep
northerly wind wave happened to coincide when the boat, the
(24:21):
Spiorn was rolled to starboard at the same moment as
she was pitching over the head on C swell. In
those long intervals where the C swell was absent, the
wind wave rolled us to starboard about once every five
seconds without there being any pitching component. I could feel
little effect from the southeast or northwest swells. After nightfall,
(24:43):
we steered by the stars, the swells remaining unchanged except
that the wind wave declined. So that's about like trying
to understand that they're different. In fact, there are multiple
swells at any given time, probably hitting you from different directions,
and so the experience navigator is looking or a particular
type of swell. You know that you could actually make
(25:04):
the same journey potentially and look for different swells to
steer you in aid of it. You just have to
know which ones you're feeling for. And that goes back
to the example you mentioned earlier about just like like
setting there or laying there on the boat and just
waiting to to feel the one you're looking for. It's
not just okay, the waves you're hitting me, I got
(25:25):
the pattern. No, you're looking for the specific pattern amid
the noise or amid the waves right when there may
be multiple patterns coming at you at the same time.
You're just trying to pick the right one out, get
the timing right to understand, yes, this is it. But
as you were talking about earlier, I think it's important
to remember and again, well we'll get more into this
in the next episode. The ability to detect and measure
(25:46):
swells in their direction of origin is not useful just
in steering on the open ocean, but it's also one
of the techniques for understanding when land is near. Now,
there are a couple of other things that are really
interesting about navig aiding on the open ocean. There's one
more orientation technique that is even less reliable than the others,
but it is sometimes still used as a backup. That's
(26:08):
known as the wind compass. So it's it's basically operating
on the presence of known wind patterns to give you
indications about about directionality. So you might, for example, use
the aid of a tool here, an external tool like
a pennant, the you know, kind of flag object that
would allow you to determine patterns of winds and where
(26:29):
they come from. And if you know that there are
certain dominant patterns of winds, you can kind of use
that to give you another data point in orienting your
boat in the right direction. Now, there's a whole other
world of ad hoc adjustment that needs to take place
on top of everything we've already been talking about. You know,
basically everything we've been talking about is getting the correct bearing,
(26:52):
knowing you're going in the right direction towards your target
island based on your starting point. But of course in
sailing you can always just sail in a straight line.
Right winds and ocean currents will gradually shift you off
course and you have to understand how that's happening and
compensate for it. Which again this is one of those
things where I just like react to that, thinking like
(27:15):
it seems impossible, how could you do it? But but
they have methods that they can do it. And there
are a lot of methods here, but for example, one
that I really liked, Lewis discusses on the first stage
of one journey with hip Hoor, departing from pula Wat,
hip Hoor would keep track of back bearings on the
island that they were leaving to see how the current
(27:38):
was affecting their heading. So you have the reference point
of the island, landmarks the island you're leaving, and then
you can see from your heading as you're leaving the
island how strong the current is at the moment. And then,
to to read from Louis here quote if said hip
Hoor it turned out on further observation to be weak,
(27:59):
we would head towards It's the point where vegas set,
which is about at three hundred and nine degrees if strong,
as proved to be the case towards the setting point
of the pl A D s at about two hundred
and eighty five degrees. Thus there were at least two
distinct star courses traditionally laid down for this passage, and
probably four to allow for strong and weak south flowing currents.
(28:21):
This was a north flowing current. So not only do
you need to know the right headings for uh, for
the island you need to get to under you know,
basically like neutral conditions, you also have to know what
headings you would use if the current is a certain
strength in a certain direction and the corresponding guide stars
(28:41):
of course, um. But so if the wind or current
is moving you laterally off course while steering in the
open ocean, and so you don't have like, you know,
back bearings like an island to refer to. How would
you even know it? How do you know how far
off course you're getting blown by the wind. This was
another moment where the technique was revealed and was like, oh,
of course, I thought this method was ingenious. Some of
(29:04):
the navigators here would look at the wake left behind
by the boat. So if if leeway I mean, you know,
wind the blowing the boat sideways in addition to forward.
If leeway is affecting your course, one way to judge
this is by looking at the degree of the angle
between the straight line you're attempting to steer on. So
(29:26):
you can imagine a straight line going from the stern
to the bow of the boat, you know, and just
going off towards the horizon in every direction. Look at
the angle between that line and the trail of wake
left behind you. This might be kind of hard to
visualize without a without a picture, so I'm sorry, but Rob,
I've got a picture for you to look at. Here
you can see that there's actually an angle of difference
(29:49):
in between the wake behind the boat as you're getting
blown off course and the straight line that you are
attempting to steer on. Yeah, you can imagine it is
looking back and saying, not a straight wake behind you
going back to you know, to just directly behind you,
as if it is a line drawn from the rear
of the vessel, but something that is diagonal because because
(30:12):
of the way the wind is blowing the vessel from
the side right. So by seeing that angle and how
large it is, a master navigator is able to correct
for the amount of leeway that they're being blown off course.
Now there's a huge thing that we haven't gotten into
(30:34):
in detail yet here, but a big section of Lewis's
book is about the Pacific navigation forms of dead reckoning,
and dead reckoning is estimating the position of your boat
without reference to any new markers around you, but rather
by knowing your past position and estimating how far you
(30:54):
have traveled from there and in what direction. So this
is crucial to keeping track of your journey. But this
is a different thing because it's not giving you new
information from your surroundings. It's rather a sort of keeping
track of your position on a mental map by just
using the information already in your possession. And one mental
(31:14):
tool that seems to help with this process and Pacific
navigation has been referred to as attack. Again, this is
not a means of acquiring new information from the environment,
but rather a visualization or a mental reference system for
understanding one's place in relation to other things. Unfortunately, this
is yet another concept that is kind of hard to
(31:36):
explain without visual aids. But Rob, I've got a visual
aid for you to look at here, and I will
do my best to try to explain it. Basically, it
hinges on having this mastery of relationships between stars, vantage points,
and various geographical locations, specifically islands on in the nearby surroundings.
(31:56):
So as a point of analogy, imagine that you want
to travel between New York in Chicago by stars. One
way that I can help understand where I am along
my journey is if I have a third reference point
in mind. So let's say Atlanta. So I know that
I start in New York, and when I start in
(32:16):
New York, I know from where I am, Atlanta is
going to be under Star A from my point of view.
So if I wanted to travel to Atlanta, I would
take my beer, I would head towards Star A on
the horizon. But by the time I reached Chicago, now,
because I'm at a different vantage point, Atlanta is underneath
Star C from my point of view, and there's a
(32:38):
midpoint in between Chicago and New York where Atlanta, from
my vantage point is underneath Star B. So the whole
time I never see Atlanta. But this mental reference system
allows me to break my journey into recognizable segments where
I keep track of each time the third reference island
or in my analogy, Atlanta has moved under a new
(33:02):
star from my point of view. Does that make sense? Yeah,
I think so. And this this visual reference helps a bed. Yeah,
I'm sorry you folks at home can't see it, but uh,
actually you know if you do, if you do just
a Google search for etach reference points, I don't think
you will find the exact um illustration that I'm looking at,
(33:23):
but you'll see some that are similar to They give
you an idea of what we're talking about. It's e
T A K. Yeah, though it's complicated by the fact
that this appears also to be the name of a
like a car navigation system, uh software. So if you
if you Google attack islands there you'll see the right illustrations. Yeah, yeah,
(33:45):
that'll cut out some of the car stuff. But I
think this system is is also really interesting because it
I think it still is important to think of it
as a useful tool for navigation, even though it provides
no additional information to the navigator. Instead, what it is
is it seems to be that it's useful as a
system for mentally keeping track of the information you already have,
(34:10):
for knowing how far you've come, where you are, and
how far you have left to go. Uh, which is
interesting because I mean, obviously that's an important part of
of any travel, right, is sort of visualizing the whole
of your journey in ways they're not immediately apparent to
your senses. Yeah, and I guess as in modern travelers
with modern instruments, being at sea or on land, Yeah,
(34:33):
we're still engaging in some level of that. We still
have some level of a mental map, but we have
these other tools that make our mental map less important.
Maybe sometimes the mental map is even incorrect. Like you know,
if you're if you're relying heavily on a GPS device
to drive you from one point to the other. I
guess you could theoretically not know if you're really driving
(34:56):
north or west or south or what have you, as
long as the system got you there. But in this case,
the mental map is everything. The Milton in the mental
map has to be carefully cultivated using uh knowledge of
all of these environmental cues, these different systems. Uh. It's
it's really quite quite amazing. Uh it's uh yeah, it's
(35:18):
it's it's something else. So when you're driving somewhere new
that you've never been before with the aid of a GPS,
you know, like a map, SAP on a phone or something.
Can Can you just plug it in and go? Or
do you, like me strongly prefer to look at the
whole route first. Um, I tend to just go the
(35:39):
same way I do recipes for meals. It's just I
just trust that. I mean, I look and make sure
I have what I need. In the same case, I'll
look at my gas tank and make sure I have
enough gas to get where I'm going. I'll see how
much how long it says it's gonna take for me
to get there. But then I'll just go I'll just
start cooking, or I'll or I'll just start driving and
(35:59):
trust that I will get there and I'll figure out
on the way of there any snakes. This must be
differences in personality type somehow, I guess I'm I'm more
annoying about this or something. I really don't like having
to navigate based on just a moment to moment directions
on an app without seeing the entire route first. I
like to look at the whole map, see what the
(36:21):
steps are, see how far it is, see like see
it visually represented. That really matters to me for some reason.
I mean, I might glance at it if if I
know there's going to be some weird exit, if it
says that, oh, I'm getting off at this exit, and
normally I don't do that. I'm kind of curious what
route I'm taking then, But otherwise I just go, well,
you know. The weird thing is, I think one reason
(36:42):
I do that, it's not like it usually gives me
important information that I actually need in addition to whatever
the step by step instructions in real time are. Instead,
I feel like it's something closer to the attack system,
where I just want to be able to visualize in
this app stract way the whole of the journey and
sort of imagine where I am along the journey at
(37:05):
various points. M yeah, but I feel like I'm going
to do that anyway as I drive, Like there's kind
of a perhaps a less accurate version of that that's
going to be going on in my head. But it
says it's as accurate as it needs to be. Yeah,
Like if the GPS satellites were to suddenly get taken
out by aliens or something, um, you know, I could
I get backtrack or even if it's if I've driven
(37:28):
this particular route before, I can probably remember the rest
of the way. Um, But otherwise I'm good. Well, I
wonder if we should call part two there and then
come back in part three to talk about one of
the next really interesting things, which is all of this
has been mostly about navigation, direction finding and navigation, especially
on the open sea, but a whole other part of
(37:48):
this science of navigation is land finding. When you're getting
close to an island, how do you know that and
how do you find it? And so let's save that
for part three. Yeah, part three, we will we will
make landfall or try to make landfall appropriately. All right.
In the meantime, if you would like to check out
other episodes of Stuff to Blow Your Mind, you know
where you can find them in the Stuff to Blow
(38:10):
your Mind podcast feed. We have core episodes of Stuff
to Blow Your Mind on Tuesdays and Thursdays. On Monday's
we do a little listener mail. On Wednesdays we do
short form episode we're calling it the Artifact, and then
on Friday's we do Weird How Cinema. That's our time
to set aside most of the science and the culture
and just talk about a weird emotion picture and then
(38:31):
we have reruns on the weekend. Huge thanks as always
to our excellent audio producer Seth Nicholas Johnson. If you
would look to get in touch with us with feedback
on this episode or any other, to suggest a topic
for the future, or just to say hello, you can
email us at contact. That's Stuff to Blow your Mind
dot com Stuff to Blow your Mind. It's production of
(38:57):
I Heart Radio. For more podcasts, my heart Radio. This
is the i heart Radio app, Apple Podcasts, or wherever
you're listening to your favorite shows.
Stuff To Blow Your Mind News
Hosts And Creators
Robert Lamb
Joe McCormick
Popular Podcasts
United States of Kennedy
United States of Kennedy is a podcast about our cultural fascination with the Kennedy dynasty. Every week, hosts Lyra Smith and George Civeris go into one aspect of the Kennedy story.
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com