With weather turning against him, the
crew of the Agalas 2 push forward into
the ice. Their only hope of finding
Shackleton’s endurance lies with an AUV.
A robotic scout sweeping the seabed and
mapping every contour in search of
something unnatural. But 30 hours into
the mission, the AUV is scheduled to
surface and check in. The screens remain
blank. No signal, no contact. The wreck
they’re chasing may be lost, and so is
their only machine capable of finding
it.
[Music]
[Applause]
In 1914, Sir Ernest Shackleton aimed to
be the first to cross Antarctica by
land, setting out on the Imperial Trans
Antarctic Expedition on board the
schoona Endurance. In January 1915,
Endurance became trapped in thick pack
ice off the Ked coast in the Wed Sea and
drifted for months. After breaking apart
on the 21st of November 1915, it sank in
water 3,000 m deep. The expedition’s 28
men spent months a drift on ice flows
hundreds of miles from land. As food ran
out, the team resorted to shooting the
expedition dogs to eat. Becoming
desperate, they sailed their three
lifeboats and reached the uninhabited
Elephant Island, where they survived on
seal meat and penguins. Shackleton and
five others took one of the lifeboats,
the James Ked, and sailed 675 nautical
miles of open sea to South Georgia, then
climbed a mountain to reach the other
side of the island to seek help. In
August 1916, after 467 days on the ice,
the remaining expedition members were
rescued from Elephant Island. All the
men survived. The loss of the ship and
the epic story of Shackleton and his
crew’s determination to survive made
Endurance the most sought after
shipwreck in the world. The idea of
finding the remains of Endurance has
captivated maritime historians and
archaeologists for decades. Several
expeditions to find endurance have
failed.
In 2019, the Netherlands-based Flatillaa
Foundation funds a non-government
research expedition to the Wed Sea in
Antarctica. The Wed Sea Expedition 2019
sets out to conduct a 45-day research
and exploration along the body of water
between the Antarctic Peninsula and East
Antarctica. This area of the sea is
notoriously difficult to access, and no
ship, including Endurance, has ever been
known to navigate through safely.
Although the charity’s main goal is to
conduct scientific research, the
secondary goal is to locate Endurance,
which is thought to have sunk 150
nautical miles east of the Larsen Sea
ice shelf. The ice around the Endurance
search area might be too difficult to
access, so the team decide on a backup
search for the ship Antarctic. The
Antarctic is also a prize ship from the
Swedish Antarctic Expedition team led by
Dr. Otto Nordkold which sank in 1903
around 25 nautical miles from Plet
Island near the northeastern extremity
of the Antarctic Peninsula. The Wedca
Expedition 2019 is led by Dr. John
Shears, whose 36 member multinational
team is made up of scientists,
researchers, specialists, and
technicians from the UK, USA, Russia,
Norway, Netherlands, Austria, South
Africa, and New Zealand. Professor
Julian Dowsell, the chief scientist,
leads the scientific team. Menson Bound,
who’s an accomplished shipwreck hunter
and marine archaeologist, is tasked with
supervising the search for and survey of
the historic wrecks in the Wed Sea.
Because of Antarctica’s harsh
environment, the window of opportunity
for conducting any field study is brief
and restricted to the southern
hemisphere’s summer months from November
to March. In the Western Wed Sea, the
main factor that determines the timing
of marine research is sea ice, which can
be as thick as 2 m. The mission has a
better chance of reaching the Endurance
search site between the end of January
and the beginning of February when the
sea ice has retreated somewhat.
[Music]
Only a handful of ships in the world are
strong enough to attempt a journey into
the wed sea. The team begin by looking
at the Russian icebreaker Merman, a
massive vessel capable of breaking
through thick ice, but it lacks the
specialist research facilities they
need. Next, they consider the Swedish
Odin, a proven veteran of polar
expeditions, but it isn’t available for
charter during the narrow summer window
of opportunity. One by one, the options
fall away. What they require is not only
a ship with power, but also one with the
flexibility to serve as a floating
research base. They need laboratories,
workshops, and crucially, a moon pool
that allows them to launch underwater
vehicles safely when the sea ice closes
in around the hull. In the end, only one
vessel fits all the requirements.
The group decides on the SA Augustus 2,
a polar research ship that cost $161
million to build and is run by the
Department of Environment, Forestry, and
Fishing on behalf of the South African
government. Named after the southern tip
of Africa, the SA Galis 2 isn’t just
another supply vessel. It’s a
purpose-built polar research ship
designed to survive in one of the
harshest regions on the planet. At 5
knots, the Agalas 2 can crack ice up to
1 m thick. At 134 m long, it has the
strength to crack through ice while
still carrying enough fuel and supplies
to make the long voyage from Cape Town
to Antarctica and back again. Its heated
decks keep ice from building up in
sub-zero temperatures, while a moon pool
at the center of the hull allows
submersibles to be deployed directly
beneath the ship, even when surrounded
by ice. On board there are cabins for a
100 scientists and crew, workshops,
laboratories, cranes, and even space for
helicopters. It’s powered by diesel
electric engines driving twin
controllable propellers, giving both
range and the ability to maneuver with
precision in the ice. For this
expedition, Captain Knowledge Benu
commands the vessel with his experienced
South African crew, working alongside
international researchers and
archaeologists. Every part of the ship
has been designed with one mission in
mind, to carry people safely into the
frozen continent and bring them back
again.
In January 2019, Augustus completes a
resupply of the South African National
Antarctic Expedition Research Base. The
expedition crew fly into Thimble Ice
Shelf about a 100 miles south of the
base to meet a Gulus for their journey
south. 7 days later, they reach Lars and
Sea site at the end of the month. The
team start their research of the marine
environment and ice from on board Agalas
2. They send an autonomous underwater
vehicle or AUV to map the subca
environment. The team has two Ksberg
Huggin free swimming autonomous
underwater vehicles from Ocean Infiniti
along with technicians from the company.
The 6.2 2 m AUVs have cuttingedge
navigation systems and a variety of
sensors for mapping the landscape,
taking temperature readings and
measuring depth. The AUVs are built to
run continuously for 60 hours at a
maximum speed of 6 knots and can operate
in depths down to 6,000 m below the
water line. The AUVs have been set up to
conduct surveys of the seafloor looking
downward and surveys looking upward
beneath the ice. They use an underwater
ROV to film and fill in any detail that
the autonomous vehicles can’t pick up.
Eclipse Group provides and operates the
generalpurpose ROV. It can recover
objects underwater and has lighting and
video capabilities for highquality video
capture. The team can explore and get
closer to the seafloor with the ROV to
record the geology and marine life. and
they fly remotec controlled aircraft and
drones over the ice pack to build a
picture of the entire area. They’ll use
the same technology to search for the
wreck of endurance.
At the start of the expedition, the
pressure housing in the ROV explodes at
a depth of 3,000 m during a test dive. A
Galis heads to King George Island hoping
to collect replacement parts, but the
weather deteriorates and the parts can’t
be flown in. The team has a limited
window to get to the wreck site before
the sea ice closes in. They decide to go
directly to the endurance search site.
Satellite charts provide the crew with
fine grain sea ice imagery which helps
them navigate the flows. The route is
challenging and the ship could get stuck
in the pack ice. But the crew on board
Agalas 2 have an unusual technique for
breaking the ice. One technique that ice
breakers use is to rock from side to
side. If you watch my video about the
development of ice breakers, you’ll see
that they pump ballast water from one
side of the ship to the other. But
Agalas doesn’t have that technology, and
so they swing the ship’s crane from one
side to the other, which rocks the ship
and loosens the pack ice enough that
they don’t get stuck. They break the ice
as they go and move slowly at about 3 to
5 knots, puddle hopping from one patch
of open water to the next. Even though
the team don’t expect to see so much
wildlife in such a remote area, in the
open water, they’re accompanied by mink
whales and emperor penguins. And when
the ship grinds to a halt, they’re
surrounded by hundreds of crab eater
seals, a name they don’t deserve because
there are no crabs in Antarctica.
[Music]
To narrow the search, the team turned to
the records of Shackleton’s master
navigator, Frank Warsley. With only a
seextant and chronometer, Wley fixed
their position in the featureless
expanse of the wed sea. It was an
extraordinary feat of skill, relying on
quick glimpses of the sun through the
clouds, painstaking calculations, and
the steady hand of a sailor who knew his
instruments better than anyone alive. On
the day Endurance sank, the weather was
against him. But when the skies cleared
the following morning, he recorded
precise coordinates. 68° 39 minutes
south, 52° 26 minutes west. Even then,
ice drift meant that the numbers could
only be an approximation. Modern
searches now use Wley’s entries as a
starting point, mapping out a grid of 72
square nautical miles. Somewhere within
that grid, 3,000 m below, lies the wreck
of endurance. On the 11th of February,
the team on board Agalis 2 arrive at the
last set of coordinates that Wley
recorded. The expedition team allocate 5
days to find the wreck using an
autonomous underwater vehicle. Unlike an
ROV, an AUV isn’t tethered to the mother
ship. Instead, it’s programmed and runs
its course independently. The team
wastes no time. After 4 hours, the AUV
is in the water and starts the search
for anomalies at the bottom of the
ocean. The AUV maps the seafloor using
its side scan sonar and multi-beam
echosounder with a resolution of 10 m to
half a meter. The AUV has other sensors.
If the wreck is heavily covered by
sediment, the AUV’s magnetometers and
subbottom profiler can identify
abnormalities in the flat seabed and
locate metallic objects from the wreck.
The AUV also has an HD camera to record
the scene. Like a lawn mower, the AUV
moves back and forth across its
programmed search area in a straight
line search grid. It’s programmed to
follow 11 lines in the search pattern
during a 44-hour dive. The team will
only know the results of the dive when
the drone is recovered and the data is
downloaded for analysis. Recovering the
AUV is difficult in the severe sea ice
conditions. The AUV sends a regular
signal with its location and if it loses
contact with the ship, it’ll
automatically go up to a specific
location to be recovered. But if the sea
ice has closed over its location, then
it’ll be trapped below the ice. As the
sea ice closes in, the captain needs to
maneuver a Gulus to keep a gap open to
recover the AUV. At 30 hours into the
dive, the AUV has completed seven lines
of the search grid. When the operators
lose contact, they wait a few minutes
and check the designated recovery
points, but the AUV is nowhere to be
seen. the team’s communication with the
AUV is lost.
It’s possible that the battery lost its
charge, which can happen to batteries in
a cold environment. The AUV is neutally
buoyant during mission operations and
carries two 17 kg drop weights, one aft
and one at the fall. And it has a beacon
so the team can find it easily at the
surface. When the AUV loses power, the
weights fall. The AUV surfaces under the
ice and because it can’t see the sky
from under the ice, its beacon doesn’t
work. A search operation is launched to
find the AUV. Normally, the ROV is
deployed to find the AUV under the ice,
but it’s out of order and still waiting
for a spare part. The floating ice makes
the search even more difficult. They fly
the drones over the ice to try and find
the AUV from above, but the temperature
drops and the search is canled for
safety. The AUV is left behind and the
Wedca 2019 expedition ends in failure.
The 2019 expedition ends in bitter
disappointment. Their cuttingedge
autonomous vehicle vanishes beneath the
ice, never to be seen again. Without it,
the search is impossible. The Agalas 2
turns back, carrying a crew who know
they came close, but ultimately failed.
For a ship already steeped in legend,
Endurance lives up to its name of
defying discovery once more. But the
dream doesn’t die. For three long years,
the wreck remains out of reach. But
momentum builds, the Falkland’s Maritime
Heritage Trust steps forward with
funding determined to finish what others
had started. By 2022, the same vessel,
the same leaders, and a larger, better
equipped team are ready to try again.
In 2022, the Forkland’s Maritime
Heritage Trust funds the Endurance 22
expedition to search for Endurance. The
Falkland’s Maritime Heritage Trust has
experience, successfully finding German
warships that sank in 1914 during the
Battle of the Falkland Islands. Because
Agalis 2 is one of only a handful of
ships to reach the far-flung Wed Sea,
the Foundation uses the same team from
the Wed Sea 2019 expedition and the same
vessel, Agalis 2. Along with finding and
examining Endurance’s wreckage, the
foundation also wants to spread
awareness and teach youth across the
world about the southern latitudes that
they call home. The science program
includes a study of sea ice parameters
and a ship’s reaction to the challenging
ice and water conditions. The expedition
is once again led by Dr. John Shears
with maritime archaeologist Menson Bound
once again in charge of the search for
endurance. Overall, the team’s composed
of 65 worldleading scientists,
engineers, technicians, pilots, and
filmmakers along with the highly
experienced crew of the Agalis 2. On the
5th of February 2022, Agalis leaves Cape
Town, South Africa on a 10-day, 3,250
nautical mile voyage to the Wed Sea. A
crew at the South African Weather
Service guides agis between two low
pressure systems forming, helping them
steer clear of choppy waters and
potentially damaging waves that range
from 9 to 12 m. They provide daily
weather briefings, analyzing the icy
conditions the team faced throughout the
voyage. Along the way, the team on board
agis drop Argo float wave spotters in
the water at each latitude line along
the route. As part of the research, the
Argo boys gathered data on the Southern
Ocean’s temperature, salinity, pressure,
and elements like oxygen, pH, nitrates,
and chlorophyll.
On the 16th of February, the Endurance
22 team arrives at the Wed Sea. As
expected, the sea is covered with ice,
but the ice conditions are a lot better
than the last attempt, and Agalis can
cut through with ease. The team is
assisted by scientists from the drift
and noise polar services who specialize
in ice navigation for sea icegoing
vessels. They help the crew navigate a
safe route to the search site by using
its ICC app, a map-based program that
provides near realtime sea ice
information. Specialists from the German
Aerospace Center are also on board to
aid navigation by giving access to
highresolution satellite photos that can
differentiate between thin ice, ridges,
and individual ice flows. The research
team maps the ice with thermal infrared
imagery, which gives temperature maps
that show more detail of the ice
conditions. Researchers from Stella
University in South Africa place sensors
around the ship to find out how Agalis 2
reacts to wave action and the impact of
ice on its propulsion system which
causes vibrations throughout the ship.
As the Agalis 2 moves through the sea
ice, a German ice scientist from the
Alfred Wgner Institute hangs an ice
thickness probe at the starboard bow of
the ship to monitor the sea ice
thickness in real time. The information
gathered from the sensors complements a
Finnish university study which aims to
better understand how ships respond to
ice loads in order to improve the design
of ice breakers in the future. In case
the 2 can’t reach the search location in
the ice, the team prepares two utility
helicopters to transport them and set up
a temporary ice camp where they can
lower an AUV through a hole drilled in
the ice. But that isn’t needed. Agalis
is able to cut a safe path through the
ice directly to the wreck site. Deep
Ocean Search is the team in charge of
locating and documenting the wreck of
Endurance under the guidance of Menson
Bound. To find the wreck of Endurance,
the Deep Ocean search team defines an
area where the underwater vehicle will
survey. The team has established a wider
search box of 15x 8 nautical miles or
120 square nautical miles, about half
the size of New York City. Two new
Saber-tooth autonomous underwater
vehicles are prepared by the Deep Ocean
Search team. The Saber-Tooth is
manufactured by the Swedish Aerospace
and Defense Corporation. It’s a
hatchbacksized hybrid AUV ROV that can
operate in the most hostile conditions
at depths over 3,000 m. It can be set up
to operate autonomously with sonar. But
for its first mission, the Saber-Tooth
is controlled from the surface using a
fiber optic tether and outfitted with
sensors, lights, and cameras. The fiber
optic tether is used to transfer data
from the sensors and camera and to
control the AUV. The Endurance search
site is covered in ice as thick as 1.4
m. Finding a shipwreck is usually
difficult and dangerous, but surveying a
region of the seafloor covered in thick
ice requires meticulous preparation.
accurate data and an understanding of
the direction and speed of the sea ice
drift. And Saber-Tooth can only dive
under the ice for 9 hours at a time. So,
the team use all the data they have to
update the underwater operations and
optimize the dive. The captain guides
Aalis through ice fishissures and gaps
and into position to launch Sabertooth
from the rear of the ship.
The days get shorter and the
temperatures drop considerably as the
Antarctic seasons change. To avoid
getting frozen in, the team works 24
hours a day in sub-zero temperatures to
find endurance. As the temperature
reaches minus 35° C, the equipment
freezes. Equipment failure is a major
issue for the team because they’re
already under a lot of pressure. The
Saber-Tooths are pushed to the limits of
their design capability. The AUVs aren’t
accustomed to going so deep in such cold
water where icicles form as soon as
they’re hauled out of the water.
Temperatures on deck reach as low as
-20° C. The extremely low temperature
has a significant impact on the winch
and fiber optic cable which become
brittle at very low temperatures. The
fiber optic cable is several miles long
and it breaks at multiple points. So the
team cut the cable into new lengths and
respspool it. The team put up a tent on
the off deck with an ice camp heater to
keep the AUV operations running. Then a
Gulus gets stuck in the ice. As soon as
they stop moving, the ice starts to
close in around them. The crew does
everything they can to break the ice
around the hull. They power up the
engines and rock the ship from port to
starboard, using the crane to shift the
weight from side to side. Agalis manages
to free itself after being trapped for a
full day. They often get stuck briefly
and have to wait until the ice releases
them. As winter draws near and the
temperatures continue to plummet, it’s
up to Dr. Shears to decide when to halt
the expedition for the team’s safety. In
10 days, they cover nearly 80% of the
search area. They have less than 3 days
in the ice before winter forces them to
return to Cape Town. On the 5th of
March, the nose-mounted camera of the
Sabertooth captures a grainy image of a
wooden bulkhead at 3,08 m at coordinates
of 68° 44 minutes 21 seconds south, 52°
19 minutes 47 seconds west, just 5.4
nautical miles from Endurance’s last
recorded position. Before they can
confirm that this is the wreck of
endurance, the AUV’s batteries run low
and they have to bring it up to
recharge.
The winter clock is ticking. They found
something and they need to get back as
quickly as possible to find out if it’s
endurance. They change the payload and
install a side scan and multi-beam
sonar, plus a highdefinition camera to
replace the sensors on the sabertooth.
One of the parts malfunctions and it
takes eight hours for the engineers to
resolve the issue. While Agulus drifts
with the ice, ending up in the wrong
position for the dive, Captain Benu
maneuvers a Gulus as close as they can
get in the ice. The AUV’s journey from
the surface back to the wreck takes
another 2 hours. Almost 12 hours have
passed by the time Sabertooth gets back
to the wreck. At 4 in the morning, the
senior team members watch the monitors
in the main control room as the drone
approaches the wreck. It moves up close
and pauses. Then it moves from bow to
stern and hovers above the top of the
wreck. Although the vessel is crushed,
the wreck is intact and in remarkable
condition, as if it recently sank.
Because of the intense cold, lack of
light, and relatively low levels of
oxygen, its timbers are well preserved.
Organisms that normally consume a sunken
wooden vessel don’t thrive in this
environment, but there are creatures
like sponges and kryinoids that have
made the wreck their home. As the drone
approaches the stern, the monitors show
the rudder resting on the seafloor, and
etched into the stern directly below the
handrail is the name Endurance.
Below the name is a five-pointed star, a
holdover from before Shackleton bought
the ship. With only 6 hours of practical
work time at the bottom, Sabertooth
spends that time taking photographs of
the timber and surrounding debris field.
The ship appears largely unchanged from
the final photo taken by Shackleton’s
filmmaker Frank Hurley in 1915. The
rigging is tangled and the masts have
fallen, but the hull is in relatively
good condition. The bow shows some
damage, possibly from when it hit the
seabed. The anchors are there. On the
well deck, the ship’s wheel is still
intact with all its spokes showing. In
front of the wheel is the open access
door and steps leading down from the
deck to the cabin. Shackleton’s cabin
portal is visible next to the companion
way. The funnel is still with the ship,
but no longer upright. It lies almost at
a right degree angle to the keel with
its steam whistle attached. Alongside is
the engine room skylight near midship.
There’s a boot along with several plates
and a cup. Like in Frank Hurley’s last
photos, the mast spars boom and gaffs
are all down. The team also uses side
scan and multi-beam sonar along with a
3D laser to scan the hull and
surrounding debris to produce a
highresolution 3D model. The team take
nothing but photos. Under the Antarctic
Treaty, Endurance is protected as a
historic site and so it remains
undisturbed on the seabed. For many, the
timing feels symbolic. The wreck is
found on the 100th anniversary of
Shackleton’s burial. The discovery
closes one of the greatest mysteries in
polar exploration. But more than that,
it gives the world a final image of the
ship that carried 28 men into the ice
and carried Shackleton’s legend into
history.