Poster presented by Paula Johanson at DHSI 2015 - Local Knowledge: small boat losses on LaPerouse's 1786 expedition in Lituya Bay, re-interpreted with moon and tidal data

1. Introduction
Jean François de Galaup, comte de La Pérouse led
an expedition of two ships from France in 1785,
intending to complete the second French
circumnavigation of the world. In July 1786 while
claiming Lituya Bay for a French base on the North
Pacific coast in what is now Alaska, the French
expedition lost two small boats and twenty-one
men. Recent commentators discuss the Lituya Bay
incident in terms of first contact between cultures
with gaps in understanding. To the study of
chapters VII and VIII in volume 2 of La Pérouse’s
journal, I bring a new element: using online moon
and tide databases to understand how the French
expedition could wreck their small boats in Lituya.
The softwarization of study of chapters VII and VIII
allows modern readers to understand conditions in
which the French expedition was using small boats.
The Incident
When trying to enter the bay, La Pérouse
was deeply impressed by the strong ebb
tide running out of the inlet. Small boats
sounded the channel and several times
crossed the current. The two ships entered
the channel’s S-shape turn between the
reefs and the points in good weather, in
daylight, and intended to be as high tide
went slack. Both ships were nearly wrecked
when the wind changed. Even this
experience was not enough to teach the
sailors caution Ten days later three small
boats went out intending to sound the
channel at slack and were caught in the
current. One boat was able to return. The
other two were wrecked in the rough waters
of the channel. Twenty-one men died, and
their bodies were never recovered.
Acknowledgments
David Berry describes softwarization as the
application of computation to forms of media,
historical and digital, adding: “We therefore need to
develop critiques of the concepts that drive these
processes of softwarization but also to think about
what kind of experiences make the epistemological
categories of the computal possible.”
Analysis
Julie Cruikshank discusses chapters VII and VIII thoroughly in her book Do Glaciers Listen? Like Cruikshank,
anthropologist G.T. Emmons makes it clear that in this case of first contact between European explorers and First
Nations people there were many gaps in understanding on both sides. La Pérouse wrote at the end of chapter
VIII that common experience of losing people in wrecked boats in the mouth of Lituya Bay helped the French
explorers and the Tlingit people understand each other to a greater extent than before. I focus on the expedition’s
use of small boats in Lituya because there is a gap in understanding between modern commentators and people
familiar with small boats. I can’t take every reader out in my small boat! The softwarization of study of chapters
VII and VIII allows modern readers to understand conditions in which the French expedition was using small
boats.
The ships entered Lituya Bay on July 3, 1786, after the small boats had entered and left the bay. Masters of the
small boats had taken several soundings, rowing in and out the narrow mouth of the bay and even across the
current. I wondered how it could be that they would lose two boats there on July 13, only ten days later – and
that’s when I understood. In ten days, the phase of the moon changed, affecting the tides and currents. I knew
that because as a kayaker, I look at the phase of the moon and how it affects tides in the narrows where I paddle.
To document this knowledge for other scholars, I turned to online databases for moon phases and tide tables.
I checked the phases of the moon in 1786, according to the National Aeronautics and Space Administration
(NASA) Eclipse web site. While no tide tables were ever generated for 1786, on the National Oceanic and
Atmospheric Administration (NOAA) website there are tide tables for Lituya Bay during June and July for several
years, allowing one to estimate the expected tides in good weather for 1786. On NASA’s website I found recent
years which had a lunar eclipse during the Full Moon on July 12th
, like 1786. Then I went to online records for
those years on the NOAA web site, where I found records for Lituya Bay.
The French expedition entered Lituya Bay on July 3, 1786 when the moon was at First Quarter. This phase of the
moon produces the least possible difference between high and low tides in that season. When the accident
occurred on July 13 the moon was a day past Full, causing the greatest possible difference between high and low
tides in that season. The phase of the moon had changed in ten days, affecting the tide so that with higher high
tides, the current would be much stronger and the slack between ebb and flood tide much shorter.
While the sailors knew what time to expect high tide and low tide on July 13, they didn’t understand that the ebb
current would remain strong until the turn of the tide with a very short slack. Based on NOAA records for tides in
that season, the tidal currents were stronger and the slack water between ebb and flood was much shorter than
on July 3, only about fifteen minutes instead of an hour. The current was twice as fast, and much stronger than it
had been ten days before. One boat was rolled in the current, one rode the waves by going straight backward,
and the third boat attempted rescue and was also rolled.
Conclusions
In his journal, La Pérouse wrote extensive
notes on Lituya Bay, explaining how the loss
of human life was not his fault because he
had given orders not to approach the
narrows until slack. He knew that on his
return to France a court-martial might
execute him. He likened Lituya Bay to the
bay of Toulon, which had a superficially-
similar T-shape. Unfortunately, the bay of
Toulon is shallow and has a tidal range of
about 1 foot (about 0.3 metres). Lituya is
instead a fjord: considerably longer, larger,
and much deeper than Toulon, with a tidal
range of over 15 feet (about 5 metres).
None of the expedition had ever anchored
before in a fjord. They had no idea of how
this great volume of water would respond to
tides; specifically, they did not realize how
short the slack current would be when the
tide changed from rising to falling. As well,
they had never tried to ride a current
through standing waves at a narrows.
The pilots of the small boats ignored La
Pérouse’s written orders and rowed too
close to the narrows. They did not
understand that on July 13 the current would
not go slack as early as it had on July 3.
Once caught in the current they did not
know how to run the standing waves out into
open water. Experienced sailors who
thought they were the best in the world after
surviving the challenges of rounding Cape
Horn were defeated by a strong current no
wider or faster than a small river.
What some commentators see as a story of
gaps in understanding between cultures, or
La Pérouse acting as his own spin doctor, is
first of all a story of hubris and lack of local
knowledge.
Paula Johanson
University of Victoria BC Canada and Kayak Yak website
Further information
Check Kayak Yak for my paddle group’s
story of our small boats in a smaller narrows
http://kayakyak.blogspot.ca/2006/07/cooper
s-cove.html
© Copyright Paula Johanson 2015