Fort St James January 2005 Launching the Seaeye Falcon ROV with sector scanning sonar


SubOceanic Sciences Canada Ltd.
Fort St. James Stuart Lake ROV Search Operation Report

Introduction

SubOceanic Client : The Karey and Prince Families and the Nak-Adzli Band.

Location of Search : Stuart Lake, Fort St James. The area of Cottonwood beach Government Wharf side of 2-kilometer long previous ice bridge location towards South shore of lake and outwards into Stuart Lake of an unknown distance. (see chart)

Dates of ROV Search : 08th to 15th January 2005 – Eight days of Operational Searching with ROV and Sector Scanning Sonar.

Nature of Search : ROV with Sector scanning Sonar search of lakebed for missing persons and Snowmobile.

Names of Missing Persons : Kora – Lee Prince, female, age :16
Matthew Karey, male, age :19

Make/ Model of lost Skidoo : MXZ 670 Long Track, 1997 model. Color : Yellow

ROV Supervisor/Pilot/Tech : Michael D. Wood

ROV Pilot/Tender : Ralph North

ROV System & Serial Number : Seaeye Falcon ~ Serial Number 1238

ROV Sensors & tooling : Tritech Sea Prince Sector Scanning sonar with a narrow beam, single frequency transducer of 675 kHz with a
150meter range. Hydro-Lek Single Function, 3 Jaw Manipulator.

ROV Camera Specifications : High Resolution of 480 TVL, Horizontal field of view 91 degrees, Min. scene illumination 0.2 LUX (F1.4), pick up device ½ “ CCD image sensor, Lens ½ “ Aspherical 3.8mm lens, wide angle fixed focus. Color camera mounted on a 90-degree tilt platform.

Nature of Lakebed : Variable, generally level with some depressions, areas of fixed lake weed and large clumps of rolling lake weed, areas of fine sand with scattered rocks of 3” diameter to 18” diameter, areas of fine silt over a mud and clay base of indeterminate depth.


Maximum Depth of water
in Lake areas searched : 14 feet 4 inches

Minimum Depth of water
in Lake areas searched : 2 feet of water - being 3 inches above ROV sonar and ice cover with ROV skid on lake bed.

Maximum thickness of ice
In search areas : 20 inches.

Minimum thickness of ice
In search areas : 8 inches.

Minimum surface temperatures
Reached during search period : - 47 Degrees with 60 kilometer an hour winds
giving a – 53 degree wind chill factor.

Maximum current encountered
In search areas : ¼ of a knot.

Total Search area covered over 8 day search period : 22 ice hole access locations each with a minimum 1000 foot diameter circular area searched beneath and around these locations. The majority of these 1000 foot diameter search areas overlap for thoroughness.

ROV Search Procedures with Sector Scanning Sonar and High Resolution Wide Angle Lens Color Camera on 90 degree Tilt platform

The ROV was lowered through the ice holes at each search location. These ice access holes were cut by chainsaw and were an average of 4 feet square in size.

Once the ROV was stable and resting on the lakebed directly beneath the ice hole an initial sonar scan was carried out with ranges used dependent on water depth and varying through 100 meters to 20 meters through 360 degrees. The optimum sonar speed utilized was slow and very slow with the threshold decreased to an allowable point to minimize clutter and the gain was generally set from 76 to 100 %.

In shallower areas, shorter ranges could only be used, due to the sonar beam picking up the ice cover above. Shortest ranges were at 20 to 30 meters, the longest range was 100 meters and the average, optimum range was 50 to 70 meters.

After the initial 360 degree scan the ROV Pilot would line up the vehicle (At the umbilical Tenders directions whilst he observed the ROV through the ice access hole) with the Stuart River lake outflow, generally South East or East of the search area. The reason for this first transect was that the slight to ¼ knot current moved in the Stuart River direction of the search areas. To take this as a first transect let the particulate suspension of fine sand, silt and mud stirred up from the lakebed by the ROV thrusters move away from the next 3 transect lines, which improved visibility.

This river mouth heading would be the first Transect with a heading taken and maintained using the ROV’s onboard flux gate compass to navigate out to the first 100 foot increment and set the ROV on the lakebed to carry out sonar scanning through the optimum and various ranges. Once the scan was completed the ROV would then proceed out another 100’ to 200’ chainage from the ice access hole, set down for sonar stability and scan again. This procedure would be repeated to a distance of 500’ from the ice access hole whereupon the ROV would proceed back to the ice access hole to be lined up by the Tender for the next transect, whilst also visually searching the area by camera whilst returning. Four equidistant 500 foot transects were carried out from the center of each ice access hole. In a couple of rocky, problem areas, five or six transects were made. These transects established a 1000 foot diameter searched area at each ice access hole.

Chainage distances of the ROV were established by the umbilical tender and passed on by radio to the pilot. (The ROV umbilical is marked with numbered distances every 50 feet.)

The radio operator in the ROV control van would sit alongside the Pilot to receive and pass on directions between the Pilot and tender. Observers, helpers and Radio personnel alternated between the Fort St. James Fire & Rescue Department Chief; Rob Bennett and his Personnel, the Citizens of Fort St James and members of the Fort St. James RCMP.

Each ice access hole was spaced 500’ from the last to ensure an overlap and a thorough search of the areas, giving the sonar varying angles to view the lake bed at given points. This was confirmed by observing umbilical drag marks on the lakebed from the previous ice hole location.

If suspect targets were acquired on the sonar, the vehicle would line up with the target and proceed to its position to visually establish its nature. The first, (# 1) ice hole scanned showed a strong target at 70 meters East of the vehicle. The ROV proceeded to the target and a three-foot by four-inch diameter length of chimney-stove pipe was found, upright on the lakebed. (These were being used by First Nations to place in holes in the ice and view small areas of the lakebed)

Other targets investigated were generally found to be 10 – 12” rocks in groups resembling a reef or in groups of 3 or 4. The sonar acquired single rocks and weed masses also.


Negative effects to the ROV Search Operation:

Fouling of the ROV umbilical by rocks was a problem in many areas especially when daylight was fading and visibility was limited.

Iron or metallic deposits in some lakebed mud areas searched were found to be present. This was established when cleaning the ROV thruster propellers. These propellers have water lubricated rare earth magnet bearings. The gray, gritty mud from the lakebed acted like iron filings and was attracted to these magnets.

These metallic, iron deposits affected the ROV compass on some transects making bearings difficult to maintain as did vehicles parked on the ice when the ROV passed beneath them.

The ROV has 150 watts of variable intensity lighting. This is forward looking and particulate suspension reflects the light. In poor ambient light conditions the ROV had to fly closer to the lakebed to obtain a visual image for searching and obstacle avoidance, where the ice cover is in shallow water, this proximity of the thrusters to the lakebed caused further pluming and silt disturbance with loss of visibility.

There were approximately four instances (over the 8 days of operation) of all 5 ROV thrusters freezing solid whilst in transition from one ice access search hole to another, this required defrosting of the vehicle which generally took no longer than 20 to 25 minutes in a heated container with a woodstove.

Due to the shallow waters navigated between ice and lakebed combined with limited visibility encountered on this search, the ROV camera Perspex lens ‘porthole’ has been fractured and one hardened glass light cover has also cracked. These are minor items.

The Falcon has 50 kgs of forward thrust and an umbilical of 13mm diameter which enabled the ROV to pull 500’ of umbilical along the lakebed and sometimes around rocks yet still complete the transects and target observation doglegs. Using umbilical flotation would have caused friction and fouling problems with the ice cover over the lake.


Chronological Events Of ROV Search Operation in Stuart Lake


06th Jan 05
07:05 Commence Testing and mobilizing ROV system in Duncan Facility. Mobilize Pilot tender from Campbell River to Duncan.
11:12 Arrange ROV freight to Prince George by telephone.
15:15 Pilot / tender arrives Duncan, load system and proceed to Duke Point.
08:00 Depart Duke Point on ferry en-route to Twassen.
20:15 Arrive Vancouver & proceed to Westjet cargo Section at Vancouver Airport to check in ROV system.
21:42 hrs Arrive Hotel in Vancouver to await morning flight to Prince George.

Maximum Depth : N/A
Total ROV Dive Time : N/A
Total Hours Worked / Traveled : 14 hours 22 minutes.


07th Jan 05
06:50 Depart Vancouver Hotel to Airport
10:37 Depart Vancouver Airport to Prince George.
11:55 Clear ROV system from Westjet cargo and proceed with Rob Bennett, Fort St James Fire Chief to Fort St James.
15:18 Arrive Fire Hall FSJ and set up and test ROV control system in 9-seater van.
16:15 Attend meeting in Fire Hall with Family Members, Fire & Rescue and RCMP.
17:58 Depart Fire Hall for Hotel.
Maximum Depth : N/A
Total ROV Dive Time : N/A
Total Hours Worked / Traveled : 11 hours 8 minutes


08th Jan 05
07:58 Arrive Fire Hall and prep system.
09:00 Arrive Stuart Lake.
09:20 Dive ROV and commence ROV and sector scanning sonar search for Snowmobile. Two areas of 1200’ and 1000 foot diameter covered, being locations # 1 and 2 ice access holes in presumed entry area of skidoo from West side of previous ice bridge of December 26th 2004.
17:05 ROV on surface, secure system and proceed to Fire hall.
18:05 Leave Fire Hall and proceed to Motel.
Maximum Depth : 3 meters
Total ROV Dive Time : 7 hours
Total Hours Worked / Traveled : 10 hours 3 minutes


09th Jan 05
07:55 Arrive Fire hall and prep system.
09:30 Dive ROV and Search ice access location holes # 3, 4, 5 and two transects on ice access hole # 6. Number 5 hole was the location of the snowmobile helmets and glove found by searchers in ice on South side of lake area West of previous ice bridge.
18:10 ROV on surface, secure system and proceed to Fire Hall.
19:00 Arrive Fire Hall and unload ROV & umbilical.

Maximum Depth : 3 meters
Total ROV Dive Time : 7 hours 5 minutes
Total Hours Worked / Traveled : 10 hours 55 minutes


10th Jan 05
06:30 In an early morning meeting with family member Vince Brisebois, the ROV Supervisor ; Mike Wood hands him a written request with an itemized list of GPS fixes required to be taken and placed on a scale chart to include: Matthew and Kora’s presumed snowmobile entry point onto the ice bridge, the presumed point of exit of the snowmobile into the lake, the locations of the helmets and gloves found by searchers, the West side of the ice bridges starting points on the North and South sides of the lake as of December 26th 2004, all ice access holes searched to date, the correct Government wharf lights he should have used to navigate the ice bridge and the incorrect Forestry Commissions lights that would have taken them off the West side of the ice bridge. Chart also to show wind direction of that evening.
08:38 Arrive Stuart Lake.
08:55 Dive ROV and complete searching ice access hole # 6 and search ice access holes # 7, 8, and two transects of hole # 9.
17:00 Depart Stuart Lake for Fire Hall.
17:16 Arrive Fire Hall and secure ROV system.
18:04 Arrive Motel.

Maximum Depth : 3.30 meters
Total ROV Dive Time : 6 hours 52 minutes
Total Hours Worked / Traveled : 10 hours 14 minutes


11th Jan 05
07:30 Arrive Fire hall and prep system.
08:02 Arrive lake and prep to dive ROV.
08:20 Dive ROV and complete searching ice access hole location # 9 and search ice access holes # 10, 11 and set up container and barriers at ice hole # 12 ready to commence work there in the morning. At ice access hole number 11 a log from a booming ground was encountered angled up from the lakebed to a height of 4 feet.
16:30 ROV on surface, leave Lake. Winds gusting 60 kilometers an hour.
16:45 Arrive Fire hall and carry out ROV maintenance.
18:45 Depart Fire Hall.

Maximum Depth : 3.50 meters
Total ROV Dive Time : 8 hours 50 minutes
Total Hours Worked / Traveled : 11 hours 15 minutes


12th Jan 05
07:02 Arrive Fire Hall and prep system.
07:45 Dive ROV and complete searching ice access holes # 12, 13 and start first transect on hole # 14.
16:20 Surface ROV and secure system.
16:45 Arrive Fire Hall.
18:37 Depart Fire hall for Motel.

Maximum Depth : 3.50 meters
Total ROV Dive Time : 7 hours 45 minutes
Total Hours Worked / Traveled : 11 hours 35 minutes


13th Jan 05
07:08 Arrive Fire Hall Heavy fog delays start of workday. Maintain ROV whilst waiting for fog to lift.
09:10 Depart Fire Hall for lake.
09:25 Dive ROV and complete searches of ice access hole # 14 and search hole # 15 and one transect of hole # 16 at 68 degrees compass.
17:00 ROV on surface secure system in van.
17:18 Arrive Fire hall.

Maximum Depth : 3.50 meters
Total ROV Dive Time : 6 hours 5 minutes
Total Hours Worked / Traveled : 10 hours 10 minutes


14th Jan 05
Terrace Search and Rescue team arrive previous evening with stand alone drop sector scan sonar and operator from Vancouver.
06:30 hrs In a breakfast meeting with family member Vince Brisebois, Mike Wood advises him that with the drop sonar and drop cameras, (plus the shallow nature of the lake in the search area) it would be more cost effective to maintain the search with these resources and demobilize the ROV back to Vancouver Island.
This would also extend the duration of the search fund.
07:18 Arrive Fire Hall. Heavy fog delays start of workday. Maintain ROV whilst waiting for fog to lift.
09:35 Dive ROV and complete search of ice access hole # 16, and search ice access hole # 17 and complete the first two transects of 67 and 356 degrees on ice hole number 18.
16:15 ROV on surface, proceed to Fire Hall.
16:32 Arrive Fire Hall and offload ROV and umbilical.
17:15 Leave Fire Hall for Motel.

Maximum Depth : 4.40 meters
Total ROV Dive Time : 5 hours 34 minutes
Total Hours Worked / Traveled : 9 hours 55 minutes



15th Jan 05
07:05 attend meeting with all direct family members and Terrace Search and Rescue Team.
08:15 Arrive Fire Hall and prep system.
Complete search of ice access hole # 18, complete searches of holes number 19, 20, 21 and 22.
18:30 All ROV system repacked and demobilized ready for early departure. Depart Fire Hall.


Maximum Depth : 3.20 meters
Total ROV Dive Time : 5 hours 27 minutes
Total Hours Worked / Traveled : 11 hours 25 minutes


16th Jan 05
05:00 hrs depart Fort St James for Prince George Airport and load system into Westjet Cargo section.
09:20 depart Prince George.
11:35 Arrive Vancouver and load ROV system into truck.
12:45 Depart Vancouver for Vancouver Island by Twassen ferry.
14:25 Arrive Duke Point and proceed to Duncan.
15:20 Arrived Duncan and offloading system in SubOceanic workshop.

Maximum Depth : N/A
Total ROV Dive Time : N/A
Total Hours Worked / Traveled : 10 hours 20 minutes



Summary :

Various members of the family and other members of the Nak-Adzli Band directed the search operation, with regard to which locations the ice access holes would be cut for the ROV to search.

The area West of the ice bridge to be covered is extremely large and will take a great deal of time to search thoroughly. There are doubts as to the actual location of the West side of the ice bridge as of the 26th of December 2004. An error on this position could throw the search out.

It would have been extremely helpful if GPS fixes at locations of the ice bridge faces and ice bridge starting points from the shore had been taken the day after this incident took place, well before the ice bridge expanded and the lake became a single sheet of ice. Present locations are based on estimations.

The only hard clues in this search are the locations of the gloves and helmets of Matthew and Kora.

The SubOceanic ROV personnel had tremendous support in this Search Operation from Chief Robert Bennett and all his men in the Fort St. James Fire & Rescue Department. They are a very dedicated and professional team. The RCMP Diver Mr. Dave Kokesh was a strong asset and gave SubOceanic good insight into the historical events also.

The direct family members and the Citizens and First Nations of Fort St James were also extremely helpful, friendly and dedicated, working in harsh weather conditions for many days, now running into weeks.

The Terrace Search and Rescue team’s response to this event and preparedness in coming to Fort St James to take on the search over such a daunting area is highly commendable.

We sincerely hope that success in the search is soon achieved and closure is brought to the family members and relatives of Matthew and Kora, The Nak-Adzli Band and the Community of Fort St. James.

Yours Sincerely,

17th January 2005



Mike D. Wood

Director Marketing and Operations
ROV Pilot/Supervisor
SubOceanic Sciences Canada Ltd.
Tel : 1 250 748 5156
Cell: 1 250 7011058
Web: www.suboceanic.net
Email: mike-bevwood@shaw.ca