Version 2.1 - November 14th
Seabed Mapping Cruise Report
October 18th to 31st
Pangnirtung to Iqaluit
|John E. Hughes Clarke and
Ocean Mapping Group
Dept. Geodesy and Geomatics Engineering
University of New Brunswick
Master: Cecil Bannister
First Mate: Anton Snarby
Crew: Jeff Cheater and Levi
The RV Nuliajuk is a 19m fisheries research vessel owned by the
Fisheries and Sealing Division of the Dept. Environment, Government
of Nunavut (GN). The prime mandate of the vessel is to conduct
a ~10 week fisheries research agenda off SE Baffin Island from mid
July to end of September. After that time there is a ~ 4 week window
in which useful operations can still be done in the SE Baffin
area. That time is currently being utilized for a seabed
mapping program. The seabed mapping program is funded jointly by GN,
the Canadian Hydrographic Service (CHS) and the ArcticNet NCE. The
actual mapping is undertaken by the Ocean Mapping Group at the
University of New Brunswick (UNB).
The 4 week window was broken into two legs. The first leg achieved
ArcticNet and GN objectives within the fjords around the Cumberland
Peninsula from Qikiqtarjuaq to Pangnirtung. That leg is described
elsewhere. This report describes the second leg.
The last 12 day leg of Nuliajuk Mapping in 2013 had three
As it happened, the flights in and out of Pang on the 18th and 19th
were aborted or cancelled losing two days at the beginning. To make
up for this (and to avoid bad weather) a through-night transit was
made. The end result required that one day be dropped from the
Inside Passage investigations and the first day of the CHS work
included (useful) transit data along the north side of outer
- Pangnirtung to Iqaluit Transit - 3 days
- GN Objectives: Inside Passage Small-Craft Shipping Lanes - 2
- CHS Objectives: Charting and tide gauge recovery - 7 days
The west side of Cumberland Sound is functionally uncharted. Apart
from a single reconnaissance line in 1968 that gets only within 3 nm
of the coast, there are no soundings within 10-15 nm of the outer
islands. Despite that, Blacklead Island was a well established
whaling station and mission in the late 1800's. And Inuit local and
traditional knowledge is well aware of the degree of accessibility
of that region. Prior to the relocation of communities to
Pangnirtung in 1962, many small communities existed on the myriad of
bays and inlets on the west side. Even today, hunting camps are
frequented routinely on the west side.
300 x 100 km rotated map of Western Cumberland Sound
CCGS Amundsen and MV Nuliajuk Multibeam Coverage
(underlying image - combination of CHS charts 7050 and
Notably, Inuit routinely use an "inside passage" within the islands
along the south western flank of Cumberland Sound. This includes
Popham Bay, Anderson Channel and Robinson Sound. And to avoid going
the whole way around Loks Land, they even use an undocumented route
through Lupton Channel and Beare Sound. Most transits are made in
local small craft with a draft of less than 1m. Only this year,
however, Peter Kilabuk brought his new ~ 2m draft Cape Island vessel
through this route. Prior to departure from Pang, Peter shared his
knowledge with us and this was the basis for the attempt on this leg
to provide a first precisely sounded route through this inside
CHS Central and Arctic are currently improving the charting in the
vicinity of Iqaluit. This year, a mission lead by Scott Youngblutt
utilized survey launches from the CCGS Radisson to enlarge the
available sounding data along the Pike Resor Channel, the main means
of navigating through the island chain that closes off the inner
part of the bay.
The harbour and approaches to Koojesse Bay (Iqaluit) are well
surveyed to modern standards out to a distance of ~6nm (done from
1997-2002).. Outside that, the whole area is covered with 1951-1958
vintage CHS single beam soundings (typical line spacing between
~200m (< 100m depth) and ~500m (depths > 100m). Given
the rock strewn nature of the seabed, this may imperfectly represent
all shoals in the area. Additionally, since ~ 2003, the CCGS
Amundsen has added transit EM300/EM302 multibeam corridors from the
Pike -Resor Channel. While imperfectly tidally reduced, these
corridors do represent a ~ 1500m wide corridor which has 100%
300 x 100 km rotated map of Frobisher Bay
CCGS Amundsen and MV Nuliajuk Multibeam Coverage
(underlying image - CHS chart 7050)
The aim of the 7 days allocated for this leg are to expand the 100%
multibeam coverage from the core Amundsen corridor and build new
corridors to alternate inter-island channels including Fletcher,
Bartlett and Algerine Passages.
The primary means of collecting bathymetric data is a 300 kHz
Kongsberg EM3002 multibeam. In more southerly waters these system
are typically used to ~150m depth. In the cold brackish water of the
SE Baffin Island, increased performance has been noted due to lower
attenuation and high bottom backscatter strengths. Bottom tracking
to ~ 250-320m is routinely achievable. Nevertheless, depths
exceeding this range are common.
Primary positioning is provided by the F-185 on COM1
(GGA, HDT, VTG, ZDA) at 1 Hz
Single Beam: a 38 kHz Furuno FCV-30 is the standard
fisheries echosounder on the Nuliajuk. It is capable of bottom
tracking in excess of 1500m. It is a split beam system, and also
capable of forming multiple simultaneous beams (up to 5) for fish
school shape determination. For fisheries biomass, the full waveform
of a single channel can be exported in the HAC format. No bottom
tracking is maintained in the HAC format, however, (or heave or
orientation). And when recording to an external disk (the internal
disk is too small), it slows down the ping rate and often freezes
the sonar for up to a minute at a time. Thus for this leg,
full waveform logging was not used.
Attitude and orientation is provided by the F-185 on COM2 in
EM1000 format at 100 Hz
Secondary positioning is provided by the C-Nav 3050 on COM2 in
NMEA (GGA, VTG, ZDA) at 1 Hz
Timing is provided by the F-185 via ZDA and 1PPS (Falling Edge)
In survey mode, bathymetric bottom tracking data is available for a
single channel. The NMEA DPT strings are logged by the Aldebaran
system on board. interleaved with the ship's Furuno GPS system
generating ZDA, GLL and VTG strings. The raw data are in uncorrected
metres assuming 1500m/s and no draft. Although the system is stated
to have an internal heave correction capability, it is clear that
the data is not heave corrected. As the data is time stamped, the
F-185 heave could be applied in post processing if desired.
For this leg's survey operations, these data are only used in depths
greater than ~ 250m where the EM3002 bottom tracking is lost.
A Knudsen K3200 2kW, 2 element 3.5 kHz subbottom profiler was run
continuously after the transceiver power supply board was replaced
on the 23rd. A 16ms FM pulse was used (5kHz bandwidth).
From the 28th onward however, intermittent failures of the Knudsen
PC terminated the logging. In general the high tidal currents in the
area preclude any significant soft sediment build up so little
subbottom penetration was noted.
The system received the F-185 positioning and is heave corrected
using the same source.
Example of 3.5 kHz subbottom profiler record
Western Iqaluit Anchorage - JD303 - ~150m depth - 10m
On the last day, the Knudsen was used off Hill Island with excellent
results (see figure above).
A Furuno CH-300 searchlight sonar system operating at either 85 kHz
("low") or 215 kHz ("high") is installed on the Nuliajuk. This is an
essential component for safely surveying in uncharted waters. It was
standardly used in HF mode as it is not synchronizable and this
minimized interference with the EM3002. The LF is only required for
ranges in excess of 500m anyway. It was routinely used on a 200m
range using horizontal scan at a user-selectable depression angle
(typically 5° to 10° examining 17 to 35m depths) . A forward looking
+/- 48° sector was used to monitor upcoming shoals in that
The system uses a mechanically tilted and rotated pencil beam
with a beamwidth of 4.5° at HF (10.5° at LF). The beam is
rotated in 6° steps, taking around 5 seconds to complete one 96°
scan at 200m range.
This system provides the means to robustly detect upcoming shoals at
a distance of 150m+ so that there is adequate time to turn or stop
the vessel. Due to the rocky and unpredictable nature of the
submerged geomorphology in the SE Baffin Island area, without this
system, almost none of the operations in uncharted waters would have
Positioning and Correctors:
CNav 3050 and 2000 GNSS Receivers are the prime source of precise
positioning available onboard. Real-time RTG output from the
3050 is available and the 3050 also generates RTCM differential
corrections for the inertially-smoothed GPS solution from the F-185.
Both the 3050 and the 2000 raw pseudo-range observations are logged
for PPP or PPK post processing.
CNAV 2000: The output is recorded using a serial logger.
The logged data is converted to Rinex format using a proprietary
CNAV converter that must be run on 32-bit Windows. Files are split
by the serial logger 24 hours from logging start.
Positioning and Orientation:
CNAV 3050: Is the secondary positioning for EM3002 and provides
RTCM correctors to F-185. Logged by C-Setup to a proprietary
format. Can be converted to Rinex with C-Nav converter.
COM1: configured to output GGA, VTG, ZDA at 1 Hz,
supplied to EM3002 as secondary positioning.
COM2: configured to output RTCM 9 correctors to the F-185
A CODA Octopus F-185 GPS-aided inertial navigation system provided
100 Hz orientation and 1Hz position.The position is an
inertially-smoothed differential solution reduced to the vessel RP.
Roll and Pitch accuracy are reported at the ~0.025° range (1 sigma).
The heading accuracy is supposed to be at the 0.05°
level. Real time heave is reported to be at the 5cm or 5% of
range scale. However, as with other real-time heave solutions, long
period drifting of the real time solutions over time scales of a
minute or more at a level of 5-15cm is common after manoeuvres. The
F-185 also provides a delayed heave solution ("iHeave") which is
continuously logged asynchronously with the GF-185 mcom files.
Should it be desired, those heave solutions could be substituted.
Typically one SVP per day was collected. An AML SVPlus
(SN3310), on loan from the CHS was used which records pressure,
sound speed and temperature. From this the salinity was
back-calculated. Given that the daytime air temperatures are now
below zero, almost all river runoff has ceased. Below ~ 5 metres the
water mass was almost entirely invariant. Beyond the maximum depth
of a dip (ranging from 60 to ~ 360m) the deepest temperature and
salinity reading was combined with a 300 to 500m decibar pressure to
estimate the sound speed at that depth. The Simrad S01 format
TSV file was transmitted to SIS so that, as well as an asvp profile
a valid attenuation coefficient file was generated.
On the gondola, an AML SV and T probe was installed providing 1Hz
readings continuously. A 60 second long median filter of those 1HHz
values was used to peform beam steering.
As a backup, a Castaway TSZ probe, usable to 100m was available.
Frobisher Bay SV Profiles (T and Sv, Salinity derived):
|All SV-T-S(derived) profiles
obtained in Frobisher Bay
|Map showing locations of 4
of the 5 SV profiles collected.
Anomalous differences between the surface sound speed and the
lowered probe were only noted in Lewis Bay (presumably the result of
remnant river run off). As the gondola SV probe was used for beam
steering and the surface brackish layer was thin, the consequences
Lever Arms, Reference Frames:
The Ship's Reference Frame (SRF) was established by a static survey
while the vessel was in dry-dock The survey, performed by Anand
Hiroji and James Muggah in May 2013, used the IMU mounting plate as
the Reference Point (RP). The RP local level was established as
parallel to a surface defined by a series of bollard tops (the
vessel wasn't level in dry-dock). The EM3002 is mounted
pitched up 1.98° w.r.t the SRF but is assumed to be aligned
with the reference frame in heading and roll. Any subsequent angular
discrepancies noted in the patch test are assumed to be a result of
the F-185 IMU body misalignment with the SRF.
The following offset are entered into the SIS installation fields:
The primary positioning came from the F-185 which outputs an
inertially smoothed trajectory of the RP.
- WLZ = -0.98 (the top of the white painted waterline - i.e. RP
is below waterline)
- S1X = 0.79, S1Y = 1.15, S1Z = 1.66 (EM3002
transducer offsets w.r.t. RP from survey)
- S1H = 0.00, S1P = 1.98, S1R = 0.00 (EM3002 orientation w.r.t.
SRF from survey)
- MSR = 0.21, MSP = -1.53, MSG = -1.86 (IMU orientation wr.t.
SRF from patch test)
These are entered as the elevation of the RP with respect to the
nominal waterline (WLZ). For all operations, the waterline is
assumed to be the top of the white painted band. Forward, that band
submerges and aft it is emergent (i.e.: static nose-down trim of the
vessel) as illustrated in the photos below. Throughout the 4 week
period, the draft was not observed to significantly change
(<~0.10m). The vessel was refueled at Qikiqtarjuaq and again at
The following photos were taken at the end of the cruise showing the
location of the top of the white waterline (the RP to WLZ reference
used). The vessel is slightly heeling to starboard. The waterline
top drops towards the bow and meets the actual waterlevel at about
the location of the RP ((roughly below the porthole location).
| stbd side water line
On the last day 30th October, (JD303), squat trials were conducted.
Weston Renoud will be analyzing the resultant RP PPK trajectories
(Iqaluit has a permanent observing base-station) to to see if
any squat trends can be observed from 0 to 8 knots.
Lowrance Single Beam: A Lowrance single beam sounder was used
from the larger RIB for the Hancock Harbour survey and revealed the
potential of using the RIB as an inshore survey and shoal
investigation tool. A custom conversion program was written to take
the position, bottom track and echo trace into the OMG Knudsen
format for post-processing. As well as confirming the validity of
the bottom track, the echo-trace seems promising for seabed
vegetation studies (see figure below).
Lowrance Digital Echo Trace - showing seabed vegetation
(and surface bubbles from breaking waves).
Three sections across Hancock Harbour, 29th October 2013.
would be better with a
showing transceiver/display mounting
showing antenna and transducer transom
showing detail of transducer
The Lowrance logs a 3200 byte echo trace with an associated depth,
position and time. The time, however, is relative to the start of
logging, so either a waypoint must be made at that point or the time
manually recorded. The only reason for a time fix is for tidal
reduction. There is no heave input and the draft offset has to be
added after the fact. It is not yet clear what sound speed is used
in the range estimation.
The RIB single beam is a useful tool for establishing depths in
waters too shallow or constricted for the Nuliajuk to safely
operate. On this leg the system was used just once in Hancock
Harbour. The figure to the left shows the achieved sounding
coverage (plotted with respect to the 1958 sounding sheet).
One option being considered for the 2014 field season is to install
a small swath system on the RIB to improve the usefulness of the
data that can be collected.
As with standard ArcticNet survey procedures, our prime source of
vertical referencing is to use the DFO WebTide. This provides a Mean
Sea Level (MSL) referenced elevation. Webtide is designed to
optimally reproduce tidal constituents at previously observed
stations around the Arctic. It will not, therefore, account for any
non-tidal water level forcing. It does however, elegantly cope with
the rapidly varying amplitude and phase of the tide around the SE
The newer Arctic9 model does resolve Frobisher Bay (left figure
below). The previous edition (Arctic8) specifically excluded
Frobisher Bay (central figure below). The default approach for OMG
processing is to select the nearest node of one of the three
available WebTide models that cover the archipelago (Arctic8 or 9,
Hudson Bay and NW Atlantic). When a vessel position is within the
mesh, it would make more sense to perform inter-node interpolation,
but as the mesh extents do not cover all of the inshore (cutting off
small inlets), the nearest option ensures that the mesh edges are
extrapolated into those inlets. The degree of extrapolation needs to
be limited however. Particularly for the case of Frobisher Bay as it
would be worse to apply a grossly extrapolated Hudson Bay or NW
Atlantic model inside Frobisher Bay, than to apply no tide at all.
Thus a series of model-specific masks, defining the allowable limits
of extrapolation, are used for all ArcticNet WebTide processing
(right figure below). As can be seen, prior to 2012, Frobisher Bay
was specifically excluded from application of any tidal model.
Up to the end of the 2011 field season, the Arctic8 model was used
for all ArcticNet extrapolations. Therefore all Amundsen data inside
Frobisher Bay have not had any tide applied. Only with the 2012 and
now 2013 field seasons, has the Arctic9 model been used for
multibeam data collected within Frobisher Bay. Therefore, it is
recommended that those Amundsen data be identified and reprocessed
with the Arctic9 model. All Amundsen data included and presented in
this report have had that done. But this needs to be applied to the
public online distribution.
|Arctic9 model coverage
|Arctic8 model coverage (blue)
NW Atlantic model (green)
Hudson Bay model (red)
|Polygons defining default
choice for ArcticNet surveys
prior to 2012
The newer Arctic9 model provides a first view of the likely
variation in amplitude and phase of the tide along Frobisher Bay.
The figures below illustrate the M2 constituent (by far the
strongest contributor). As can be see, the amplitude of the tide
increases up Frobisher Bay and the phase advances similarly up the
bay indicating a rapidly progressing wave.
|M2 amplitude - white line 0.1m
contours, black line 1m contours.
3.4m amplitude at head, 2.5m at mouth
|M2 phase -range : -11 to -60
degrees (1 degree is roughly 2 minutes delay for an M2 tide)
Loks Land Bypass - One of the objectives of this mission that
was not achieved was to investigate a potential navigable channel
between Loks Land and the Blunt Peninsula. A path through the
Lupton Channel and Beare Passage is reportedly used by local shoal
draft craft (most recently, Peter Kilabuk in July 2013). The Sailing
Directions, however, mention that at the northern mouth of the
Lupton Channel "a line of breakers forms from shore to shore when
a rough sea from the Davis Strait meets an outgoing tidal stream"
and "Powerful and erratic currents prevail in Lupton Channel
making navigation difficult and dangerous".
If the tidal streams are indeed so strong, it would limit the
usability of such a short cut. Examining the figures above indicates
a significant offset in both tidal range and phase on either side of
the peninsula that could produce extremely strong currents through
such a channel. The M2 tidal amplitude goes from 2.0 to 2.5m across
the peninsula and the phase of the tide is ~30 degrees (~ 1 hour)
different on either side.
The other issue that the Arctic 9 tidal model can help to elucidate,
is the typical nature of the tidal streams and their times of
reversal as the tidal wave propagates through the line of islands
that restrict the entrance to inner Frobisher Bay. The animation
below shows the magnitude and direction of the tidal streams,
inferred from the M2 constituent of the Arctic 9 model in
inner/upper Frobisher Bay. Note that the fidelity of such a model
depends on how well the shape of the inter-island channels are
resolved. Part of the aim of this mission was to better resolve
those inter-island passages. Notable, a new, large cross section
channel was in fact found.
animation of current vectors for the M2 component over one
EM3002 - depth limitation:
As mentioned earlier, much of the area surveyed is at, or beyond,
the attenuation limit of a 293 kHz system. After ~ 75m depth,
the full +/-65° sector cannot be utilized. In general, a maximum
swath of ~ 300m in muds (400m in gravels) is achieved by ~ 150m
depth which stays stable until ~ 200m after which it contracts and
dies by ~ 250m in muds (~320m in gravels). The two performance
envelope plots below illustrate the actual achieved coverage as a
function of depth, either in soft sediment or hard sediments.
|example performance envelope
in low backscatter sediments
|example performance envelope
in high backscatter sediments
for depths greater than ~ 150m, a lower frequency multibeam should
be used. As the areas covered routinely dropped in and out of the
maximum achievable depth, lots of data cleaning has been required to
edit out the mistracking in the event of an "unfathomable" bottom.
The system has to be kept logging even after the bottom tracking has
been lost in case the seabed rises up again. For those instances,
the Furuno single beam data is substituted.
The figure to the left illustrates surveys that go beyond the
extinction depth of the EM3002 off the mouth of the Falk Channel.
Reconnaisance lines were run in an attempt to link the Falk Channel
survey to the Bartlett Approaches corridor across an area believed
to be generally deep but with anomalous soundings (charted depths
are in fathoms). The Furuno 38kHz data is substituted and retains
the ability to disprove anomalous reported obstructions present in
the old chart.
EM3002 - near
nadir tracking noise:
Throughout the month, it is clear that on certain seafloor
types (generally smoother), the bottom tracking around nadir
exhibits a characteristic series of deeper spikes. While the RMS
effect of these spikes on the whole dataset does not exceed IHO
Order 1 criteria, the individual events are outside (deeper) than
that criteria. These spikes show up clearly in sun-illuminated
images (see figure to left). While many of these are caught by
the spike filter, one could not engage the filter too strongly, as
in areas of boulders, it would remove many of the boulders.
Fortunately most of the spikes are to deeper depths and thus not
biasing the bathymetry shallow.
The outliers are expressed in both phase and amplitude detections,
but most notably in amplitude detections. When the associated water
column imagery is compared to the actual bottom tracking (see
figures to left below), it is clear that the intermittent deep
spikes do not correspond to an apparent alternate
echo at that range. Indeed, for most of the mistracks, there is a
clear bottom echo within that beam trace above the chosen tracking
point that matches the tracking on the neighbouring beams (see
figures to right below that show the intensity time series for the
mistracking beam). Thus it is not actually clear why it is choosing
a deeper range?
The 2012 Nuliajuk EM3002 data needs to be reassessed to see if this
phenomena was present then. It notably degrades the fine detail
definition for the near nadir data.
Four examples of watercolumn imagery of
swaths in which pronounced deeper bottom mistracking is present.
|water column imagery - grids
spacing at 10m intervals
|zoom of watercolumn showing
intensity trace for the specific mistracking beam
EM3002 - outer
beam low S/N:
Even in shallow water, on almost any seafloor, it was apparent that
the last few beams beyond ~ 62° tended to abruptly have a higher
bathymetric noise level (see figure to right). This showed up
in sun-illuminated grids as a distorted edge to the swath (see
figure to left). Where overlap was achieved the weighted gridding
filter removed this. Nevertheless, it has not been seen on other
The water column imagery clearly show a significant drop in the
seabed scattering strength for the last few degrees on each side. It
is presumably this low S/N that is resulting in poor bottom
tracking. Even though the grazing angle is very low, in extreme
cases the bottom detection is forced to revert to amplitude
It does correspond to a poor quality factor (as defined in the old
depth telegrams, not the new Ifremer one). The phase QF is stored in
the lower 6 bits (maximum value of 64) and corresponds to the
residual to the regression through the phase values. For most
operations, the outer 5 beams on either side showed QF > 64.
Initially an attempt was made to edit based on a QF over this
threshold. But at times the data is fine and thus this would result
in artificially trimming the edge of good data.
The animation below shows 10 successive water column images
illustrating the abrupt drop in the apparent seabed echo at the edge
of the swath, corresponding to the increase in bathymetric noise.
Note that the noise is worse to starboard which in this case
is slightly downhill. Both sides exhibit this noise characteristic
It is not clear whether the low S/N in the outer edge of the swath
is a failing of the transducer beam patterns, or a result of the
installation in the gondola, or a transceiver electronic issue?
animation of 10 succesive pings
still of one ping
still of another ping
BIST tests results:
Surprisingly, the BIST tests this mission indicated passing all the
requirements. Previously the receiver noise test failed. The
actual test files are still on board, but will be added to this
report in a few weeks.
In summary, the EM3002 hardware on board (now ~7 years old) appears
to have some small, but not insignificant issues. At this time it is
not clear whether the transdcuer or transceiver could be improved by
a factory maintenance cycle. There are no confirmed plans to drydock
the vessel yet, but that may change in the spring.
A brief description is included here of all the main survey
areas/objectives. An overview figure is provided along with details
on data quality and comparisons to existing data (if it even
For all figures presented, a common colour range and contouring
schema is utilized. The upper end of the colour range (solid red) is
depths less than 20m and the lower end of the colour range (purple I
think), represents 100m. This highlights the areas of concern to
navigational charting. The contours in white are at 50m intervals to
a maximum depth of 400m (beyond the range of EM3002 tracking). The
contours in black are at 5m intervals to a maximum depth of 200m.
The resolution of the images depends on the area covered. All images
have a geographic grid embedded for registration.
Where no modern charting is present (or just small scale 7050 or
7051 chart coverage), the backdrop is the NRCan toporama topographic
map series. These are the most reliable for coastline location. They
also include a surprising amount of detail on offshore reefs, as
inferred from aerial photography. The only problem seen in these
maps is the outline of the Nunavut Land Claims boundaries which are
clearly slightly offset.
For the Inner Frobisher Bay area, charts 7121 and 7122 are
preferentially used as backdrop. Around the inter-bay islands, the
coastline agreement between the CHS charts and the NRCan toporama is
adequate (within 50m). Further out in the Bay (around Ward inlet),
the two coastline representations are off by several hundred metres.
At this time, it is not clear which is more representative although
the NRCan are generally assumed to be better positioned.
Open Water Shoal
From Imigen Island to Blacklead Island, an inshore transit corridor
is gradually being developed along the west side of Cumberland
Sound. By combining the July 2013 Nuliajuk transit and this
leg, a ~ 300m corridor is now available through an area previously
completely devoid of any depth measurements. For the majority of the
transit corridor, the depths are over 100m and often beyond
the capability of the EM3002 (>250m). For those deeper water
sections, the single beam depth from the 38kHz Furuno is substituted
(see figure to left).
Along that corridor, however, here is one notable constriction
at ~ 65° 31' N, 66° 49' W. At this point (box in figure to left and
see figure to right), on the inbound transit, a least depth of 24m
(re. MSL) was found on the eastern side. On the outbound transit on
this leg, a shoaller depth of ~ 15m (re. MSL) was observed on the
western edge. As a result, at the moment, there is only a ~ 150m
wide corridor that appears safe for navigation. These shoals clearly
represent a NNE extension of the islands to the SSW.
It is strongly recommended that the spatial extend of these shoals
be better determined to establish a wider safe transit corridor.
Cape Edwards Anchorage:
A nearby bay just SE of Blacklead Island was investigated for an
overnight anchorage. A sill with a least depth of ~ 20m was apparent
and an inner basin which is at least 70m deep is present. At the
head of the inner basin, a suitable anchorage area in < 30m is
Data was only collected during the inward bound transit as in the
morning, the F-185 required ~ 1 hour for recalibration while
to Neptune Bay:
An additional protected-water corridor can be found by diverting
into the Littlecote Channel and then out again through Neptune Bay.
While a longer route, it is completely protected from open water
swells. Peter Kilabuk reports that the constriction at the SW
extremity has ~ 2 fathoms of water. This may be too tight for the
Nuliajuk, although, once investigated, there may be a deeper
There was no time in this leg to investigate that alternate route.
When approaching the northern entrance to Popham Bay it is possible
to take a few cuts inside some of the islands. The main one is
Christopher Hall Island but there are two small islands off Jackson
Island too. Popham Bay consists of two main deep segments connected
by a cross channel . The cross channel is shallower, and has
significant currents. At the time of transit (~1800UTC, 22nd
October) the flow in the most constricted section of the cross
channel (64° 11.7'N, 65° 12.3'W) was ~ 3 knots to the north.
That time corresponded to slightly before low water at Imigen
The depths of the deep segments are preserved by integrating the
Furuno 38 kHz single beam data.
There are alternate possible passages through the islands within
Popham Bay. The original proposed route had to be modified to avoid
breaking shoals at ~ 64° 07.8'N, 65° 01.7'W which lie between two
small islands that exist on the NRCan Toporama sheets.
Cape St. David Anchorage:
Just inside the northern entrance to the Anderson Channel a very
tight, but suitable anchorage was established in a narrow and steep
sided inlet on the north side of the channel.
It is necessary to go right up to the head of this inlet to find
suitable depths (<30m) for anchoring. At that point the width of
the bay is only ~ 200m wide.
This section represents the shoallest depths encountered on the
inside passage. There are in fact three constrictions. The first two
are primary depth limited, but the third, by the unnamed island
provides a significant lateral constriction as well. This was the
location indicated by Peter Kilabuk.
At the southern end of Anderson Channel is a connecting channel to
the east that potentially might provide a clear passage to open
water. This should at some point be investigated.
|northern Anderson Channel
|central Anderson Channel
|southen Anderson Channel
Once clear of the constrictions, the passage opens up into Robinson
Sound extending down to the end of the shelter provided by Cape
Murchison. No further constrictions were encountered.
Near Monumental Island:
Originally, it was intended that a reported navigable passage inside
Loks Land be investigated. But due to deteriorating weather, the
Nuliajuk undertook a diversion seaward that passed close to
Monumental Island. That area is covered by CHS Field Sheet 285501
-Brevoort Island to Loks Land (1:72,000 1958). The depths
encountered were compared to the reported depths on that field
sheet. No significant anomalies were encountered.
Outer Frobisher Bay
and Gabriel Islands:
A single line of soundings is depicted on chart 7050 (see figure to
right) indicating a deep water passage between the line of islands
on the north side of outer Frobisher Bay. If this corridor can
be re-established and expanded, it provides a more protected route
for small boat passage through Outer Frobisher Bay. At the moment,
the preferred route for vessels is along the southern shore which is
deep and has now been extensively surveyed by the Amundsen over 10
years of multibeam transits (figure to left).
This corridor was followed (as well as possible given the
uncertainty in the registration of that small scale chart). Almost
the whole passage was greater than 100m. The shoaller areas were
clearly when the track approached one or other side of the channel
with deeper water always apparent on the outer side. At the northern
end when turning to the west, a particularly deep point (?> 300m)
was encountered suggesting a deep trough that probably could be
followed to provide a new corridor to the NW up into Ward Inlet and
ultimately up into Anna Maria Port.
It is the intention that all future transits of the Nuliajuk in and
out of Frobisher Bay will follow and expand this corridor to provide
a well surveyed alternate route on the northern side.
Bartlett Narrows and Deep Passage:
All the existing soundings on 7050 (shown in more detail on
7121 and 7122) and all the ArcticNet Amundsen transit data is on the
southwest side of Frobisher Bay leading towards the currently
preferred inter-island channel (Pike Resor). If a vessel is to
approach Bartlett Narrows or Algerine and Deep Passages, it requires
steaming through sparsely charted waters.
Therefore a new corridor was established linking the main approach
to those northern channels. The reconnaissance soundings reported
indicate that it is mainly deep immediately to the east of the line
of islands although isolated apparent shoals exist.
As the EM3002 only reliably tracks in shallower than 250m depths,
the corridor location was chosen along the NE side of the route in
depths generally about 150-250m of water.
Inner Frobisher Bay
In order to get into Inner (Upper) Frobisher Bay and approach
Iqaluit, it is necessary to negotiate a route through an "intricate
labyrinth of islands of all sizes extending from shore to shore"
(Sailing Directions, Arctic Canada, CHS ). These line of islands
have five known navigable passages based on an intense single beam
campaign by the CHS in the 1950's. As originally requested the
focus of the mapping was to be on improving the multibeam coverage
around, and through, the known inter-island passages.
The CHS have now almost completely resurveyed the recommended
corridor through the Pike Resor Channel. The Fletcher Channel,
however, is an almost equivalent conduit. The existing soundings
data from the 1950's and indicate a similar sill constriction at the
SE end of the channel. In order to better define this corridor there
was a requirement to start undertaking 100% coverage of this channel
in the hope of opening it up for more traffic.
The centre of the whole length of the Fletcher Channel deeper
than ~ 60m has now been covered. And the approaches, between the
Bird Islands and Daniel Island have been further investigated.
The deeper water to the south of the Bird Islands is all already
covered by Amundsen transit multibeam data.
The most remarkable finding of the mission was the discovery that a
deep channel exists between Falk and Fletcher Islands. Apparently
the area had previously never been investigated. The 1950's surveys
extend ~0.5 nm into the western end, indicating deep water but
abruptly terminate. At the eastern end there are three rocks awash
that are reported without any intervening soundings. The main
5 nm long channel otherwise appears completely unsurveyed.
The current Sailing Directions refer to the inter island passages
east of the Fletcher Channel and report "Air photographs show
drying ledges extending from most of the islands and most of the
channels between them appear to be encumbered with rocks and reefs".
Currently the Pike Resor Channel is the route recommended in the
Sailing Directions. The second option would probably be the Fletcher
Channel. The SE end of the Fletcher Channel, however, shares the
same lateral and depth constrictions which results in accelerated
tidal flow making navigation problematic. The more NW section of the
Fletcher Channel is both wider and deeper with correspondingly
reduced tidal streams.
The Falk Channel branches off from the wider, deeper section of the
Fletcher Channel. And the full length of the new Falk Channel is
both wider and deeper (usually over 200m depth) than either the Pike
Resor or Fletcher Channels. Although current meter measurements have
not yet been performed over a spring tidal cycle, it is strongly
suspected that the tidal streams in the Falk Channel will not be
particularly challenging (at least compared to the mouths of either
Pike-Resor of Fletcher Channels) as it is deeper and wider.
And the channel width is at least > 750m at all locations which
should allow two vessels to pass safely. To negotiate the turn at
the western end into the Fletcher Channel, over 1 nm is available in
depths > 50m.
The weaker tidal currents may result in a later opening of this
channel. One of the reasons the Pike Resor has been previously
favoured is that the extremely strong tidal streams promote early
Algerine and Deep Passages:
In July, a first transit was obtained through Algerine and Deep
Passages which was then widened as part of this mission in October.
The surveys agreed well with the 1950's data. As noted in the
Sailing Directions, however, the two ~90° turns required are
problematic for navigation. During the first July transit, on the
Spring tide flood, significant whirlpools were recognized that would
submerge large blocks of floating ice.
The approach to Hancock Harbour was covered while deploying and
recovering the RIB in an attempt to retrieve the CHS tide gauge
(unsuccessful unfortunately). The Nuliajuk did not attempt to enter
the inner harbour. A likely safe transit was noted using the forward
looking searchlight sonar, but there was no need to take any risk.
The RIB undertook a brief single beam reconnaissance of the inner
harbour and those data are presented earlier in this report.
This was surveyed at HW (Neap). The main concern is the sill between
Scylla and Charybdis Reefs. A sill depth of 16 fathoms (re. CD) is
reported in Chart 7122 and 6-7 knot peak tidal streams are present
there. A minimum depth of 28m (re. MSL) was found at the same
location. During the Neap water period, at the time of survey, no
more than ~ 2 knots maximum was observed.
The branch to the SW between McAllister Island and Culbertson Island
was not investigated. Even at neap tides, there was a pronounced
tidal front and overfalls visible at the NE end of this channel.
On JD302, to avoid the strong winds, the passage around the east
side of Frobisher's Farthest was briefly investigated. The
constriction is not quite as tight as the current chart suggests ( a
product of generalizing the contours into deeper water to best
represents the constraining shoals). The passage requires no
significant course changes and is generally protected from winds.
Whether it is open later or earlier than other passages is not known
Daniel Island Harbour:
While working on the approaches to the Fletcher Channel and the new
corridor through Falk Channel, overnight anchorage on three
occasions was obtained in Daniel Island Harbour. As a result,
reasonable new multibeam coverage of the central part of the
anchorage was obtained. The area has been extensively surveyed in
the 1950's and is a specific chart insert (712102).
The newer multibeam coverage confirms the older surveys without
significant anomalies. The main new information noted is the
widespread presence of submerged landslides. Notably, while some of
the landslides are adjacent to steeper slopes, they do not
clearly correlate with any subaerial geomorphology.
While working around the northern channels, overnight anchorage was
easiest in Lewis Bay. This bay, and Porter Inlet to the west, have
both been previously surveyed as part of the 1950's single beam
campaigns. Originally it was intended that Porter Inlet be
utilized as well. The new multibeam coverage confirm the older data
without any significant discrepancies.
The only new features of note are the widespread presence of
landslides coming off the coastal areas. These look very similar to
the phenomena seen in Daniel Island Harbour.
Western Iqaluit Anchorage:
On the last day, as we were already in Iqaluit, rather than lose 3
hours of transit to get out and back to the island chain area, we
decided to pick an area outside the modern CHS Kojeese Inlet surveys
and map that. The result was an area adjacent to Hill Island (see
figure to left). Just to the NW, a shoal region, missed in the
reconnasisance 1950's surveys had been recently surveyed using the
Amundsen barge EM3002 system (in 2010). In the deeper Hill
Island area covered, the 1950's depths were confirmed without any
October 18th: - flights both in and out of Pang were aborted
so outgoing and incoming crews not exchanged.
October 19th: - Original intended sailing date. Outgoing
flight did leave so crew departed (James, Bob, Kevin) but incoming
was cancelled so Jeff and Weston were unable to arrive.
October 20th: - Incoming flight finally arrives at ~ 3pm.
(JD294): - Departed Pangnirtung at 0600. F185 heading clearly
wrong. Rebooted and calibrated while steaming out of Pang Fjord.
Reacquired calibration and logged data on north flank of coverage.
Over Pang Sill with ~ 15m water (schools of fish on sill top
providing false targets for searchlight sonar).
Transited over deep sound, tracking bottom intermittently. Joined up
with July inboard transit on west side of Cumberland Sound. Twinned
that track. Shoal region slightly expanded (see note elsewhere) but clearly
a constriction. Diverged from inbound transit to keep in shallower
water towards Blacklead Island. Passed Blacklead at dusk ~ 2 miles
Entered uncharted potential anchorage
just east of Cape Edwards. Sill least depth of ~ 20m, but deeper
inside. Excellent anchorage.
(JD295): - Departed Cape Edwards anchorage at 0600 but F185
heading clearly wrong - waited 45 minutes while rebooted and tried
to reacquire a calibration. Finally achieved this outside harbour.
Uneventful transit until turned inshore to attempt Popham Bay transit.
Strong tidal currents observed at one constriction (see note
Rounded Cape St. David at dusk. Searched out an unsurveyed narrow
side inlet on the north side of Anderson channel for an anchorage. Eider duck impact
as entering (flew into, and apparently blinded by,
searchlight). Too deep for anchoring in outer part but ~ 20m
in inner most basin. Only ~ 200m wide though. Excellent anchorage.
(JD296): - Departed Cape St. David anchorage at 0600. F185
working well. 3.5 kHz turned on after consultation with Knudsen
Three constrictions found in
Anderson Channel. First two are shoal but not narrow. The third is
the one pointed out by Peter Kilabuk. It is both shallow and
extremely narrow requiring one to hug the west side of the central
Overnight Transit: - As we steamed down Robinson Sound past
Brevoort, the seas increased. Rising wind and swell from NE were
noted as we moved into open water. Decided it was imprudent to
attempt an entrance to the Lupton Channel as would be with following
wind and seas. Decided to steam outside Loks Land even though
requiring an overnight transit.
Headed out to SE towards Monumental Island to avoid seas on the
beam,. Then turned due south just west of Monumental Island. Passed
south of d'Iberville Rocks at ~ midnight.
October 24th (JD297):
- at dawn, transited through the line of soundings between Maclean and Gabriel
Islands. 1-1.5 knot flood tide current with us. Then developed
the first line of a corridor just
to the south of reported rock and shoal areas toward Bartlett
Narrows and Algerine Passage.
Off Bartlett, turned south and ran along the 150-200m contour to
define the eastern edge of the island chain. There are no systematic
surveys to the east of the island chain. To the west are shoals, and
to the east is the deep water (beyond EM3002 tracking depths).
Anchored overnight in Daniel
(JD298): - Departed Daniel Island Harbour anchorage at
0700. ran east across preexisting deep Amundsen coverage to a
point where EM3002 tracking depths are viable. Built a corridor
north to join the incoming transit on the 24th. Ran that up to
the mouth of the Bartlett Narrows. Once at the mouth as it was close
to HW, so we ran two lines through Bartlett
Narrows, in and back out again.
The return corridor to the south east was twinned all the way
back. With three overlapping swaths, there is now a 500m+ wide
corridor for vessels wishing to steam to Bartlett Narrows or
Algerine Deep Passages.
Anchored at 1800 back in Daniel Harbour..
(JD299): - Departed Daniel Island Harbour anchorage at
0700. Ran a constraining survey around the "Bird"
Islands (Gander, Nesters, Gosling, Kittiwake). Then proceeeded to
define the deep water
approaches to the constriction at the mouth of the Fletcher
At HW we proceeded through the mouth of Fletcher Channel, adding a
few lines better defining the multibeam coverage on either side of
the constriction and then ran a corridor up the east side of the
channel. At the north end we turned to the NE and cut the
first line of a transit corridor to Lewis Bay.
Arrived and anchored in Lewis Bay at
(JD300): - left Lewis Bay at 0700. Added two lines on either
side of the
Algerine and Deep Passage
transit corridor. And added two lines on either side of the Bartlett Narrows Corridor. Then
proceeded to expand the Fletcher Channel as HW approached. On
returning NW along Fletcher we decided to turn into the opening to
the east that lead to the gap between Fletcher and Falk Islands.
Prior soundings only extended ~ 1/2 a mile in but indicated over
200m of water.
On investigation it is apparent that there is a wide (>3/4 of a
mile) channel with typically 200+m of water all the way to the
open outer Frobisher Bay. The channel passes north of the reported
rock awash and shoals at the mouth of the inter-island pass.
Several lines were performed before heading south biulding inshore
along the reconnaissance line just to the east of the island chain.
An attempt was made to find a suitable anchorage in an uncharted bay
at the south west end of the Falk Channel
but the mouth proved to be foul.
Anchored in Daniel Island Harbour at 1730.
(JD301): - Departed Daniel Island Harbour anchorage at
0700. ran up the eastern flank of the island chain, landward
of our previous tracks. Defining the 40m contour most of the
way. Started better defining the mouth of the Falk Channel. Also established that the
two rocks awash are not part of the same reef. It is possible to
steam between the two and around to the west of the southern shoal.
The reported obstruction does not appear to exist. Investigated
shoaler soundings in the deep water between the channel mouth and
our transit corridor to the NE.
Continued to define the full channel to the 40m contour wherever
possible to safely do so. Finished at about 3pm. Headed up the west
side of the Fletcher Channel and then built on the transit corridor
over to Bartlett Narrows and Deep Passage.
Anchored in Lewis Bay at 1830.
(JD302): - up anchor at 0700. Prepared RIB for tide gauge
deployment. ~25 knot winds from the NW, with significant seas.
Dropped off at ~ 0845 in lee of island closing off Hancock Harbour.
Weston and Levi attempted to communicate with the submerged tide
gauge. No luck. Deck unit clearly transmitting and codes used were
based on the deployment log. RIB proceeded to undertake single beam
reconnaissance mapping of Hancock inlet to better define entry
depths. Nuliajuk surveying to the south, but sea states marginal for
quality data collection. Picked up RIB at about 1030. Decided to
take the shelter of Frobisher's Farthest and run the Mandarin Passage. Then proceeded to
survey just south of Lewis Bay in partial lee of coastline.
At ~1300 departed for Iqaluit to arrive before dark as freezing
spray building up on superstructure. Winds now gusting
to 35+ knots from the NW. Steaming into seas. ~ 1430 (local) noticed
that C-Nav has lost its corrections. Perhaps ice buildup on the
receiver? Not recovered until at anchor.
Anchored in inner harbour at ~ 1530. Breaking ice off
(JD303): - Picked up GN representatives at 0700. Proceeded to
Hill Island Area. Did a
CTD in 250m of water and surveyed until ~ 1500. After that we
conducted squat trials while transiting back to Iqaluit harbour.
At anchor at 1600.
October 31st: - hopefully airborne!
For the GN inside passage investigations, the most significant
finding was the validation of a viable corridor with > 10m keel
clearance through the restrictions in Anderson Channel.
For the CHS work. the most significant finding of this mission was
the identification of a previously unsurveyed, safe deep-water
passage through the island chain. No prior sounding existed at all
between Falk and Fletcher Islands. The seaward mouth had a series of
correctly reported rocks awash which presumably discouraged any
The obstruction charted east of Falk Island at 63.266905 N
-67.729099 W, reported in 1948 appears to not be present.
Similarly the charted 37 fathom (67m) spot sounding to the NE is
actually in an area > 500m.
The 102 fathom (198m) spot sounding to the east is more like ~
250m. It may however shoal within half a mile of that area.
- find way to record FCV-30 full-trace data without freezing
the real-time display.
- replace C-Nav 3050 antenna with one immune to Inmarsat
- return K3200 transceiver to Knudsen to trace power supply
- shorten F-185 antenna pair baseline to achieve faster
- add more memory to SIS-PC to prevent grid engine freezing.
- Increase OMG monitor displays from 4 to 6 screens (reduce
printer footprint also?).
- Establish procedures to log hull-mounted ADCP without
- add swath mapping capability for the RIB
- have EM3002 serviced to fix nadir noise and low SN outer
- Location Specific:
- Frobisher Bay area:
- The Falk Channel data should be used to generate an ENC to
allow shipping to start using it.
- A deep-water approach corridor should be established to
allow vessels to steam directly to the mouth of the newly
defined Falk Channel.
- Consider deploying bottom-mounted ADCP moorings in the
channel constrictions to determine current field as a
function of spring-neap cycle.
- West Cumberland Sound Area:
- Investigate the shoal
area along the open water channel on the west side of
- Investigate the feasibility of the protected inside
passage through Littlecote Channel and Neptune Bay.
- Expand the coverage of the three shoal constrictions in
Anderson Channel (would require RIB-based swath system).
- Investigate the connecting channel from the middle of
Anderson Channel to the open water.
- Attempt the Lupton Channel - Beare Passage corridor (again
- would be easiest with a RIB-based swath system).
report generated on board by JEHC -
October 19th to 30th 2013 - v2.1 finished on November 14th.