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Immediate Report of Victoria University Of Wellington Antarctic Expedition 1987-88: VUWAE 32


page 20



Surveys of the sea floor of McMurdo Sound and Granite Harbour have shown that sediment texture there is, in broad terms, bathymetrically controlled, with mud in the basins, muddy sand on the slopes and sand on the shelves. The main purpose of this project is to document the relationship between sediment texture, micro-organisms (diatoms and foraminifera) and water depth from the shoreline to the 100 m contour along the Victoria Land coast.

Sea floor sediment samples were obtained from seven shore-normal transects from Blue Glacier to Tripp Bay, plus one transect off Cape Armitage, on Ross Island. Current measurements were made at most of the 100 m sites with an TnterOcean S4 electromagnetic current meter.

The programme involved a five-person party working from the fast ice in the southwestern Ross Sea, Sea floor samples taken with a modified Shipek grab along the eight transects sampled diverse substrates and biota. The areas sampled represent a range of coastal types (exposed to embayed) with a variety of substrates, including bedrock, gravel, sand, mud and sponge mat.

Preparations for the Field

This event used several large equipment items from Scott Base which required checking and minor repair-cleaning before use. Our field assistant Geoff Blake went to Scott Base early to prepare some of this equipment and our scientific equipment. It was a little disappointing however to find more items than I expected required servicing before we could use them. This servicing should have been the responsibility of Scott Base staff. The main problems were the Cantago sledges which required digging out of the snow and servicing, NZ-1 wannigan which we had to clean twice because it was used for Scott Base Sunday excursions after we had taken possession, and the D3 servicing which is the Scott Base mechanic's responsibility, although some people thought this was our job also. There was also some confusion over generator allocation and other mechanical items which are serviced by the mechanic but controlled by the storeman. A solution to this type of problem would be for the mechanic to have both servicing and issue responsibility for this equipment. An example of this problem was that our field assistant ended up servicing two generators, one for our use and one that was allocated to another field party.

page 21

Field Transport

NZARP vehicle

We travelled on the fast sea ice by D3B LGP tractor pulling three 5 ton Cantago sledges and used a Grizzly toboggan (G4) for bathymetry surveys and route finding. The first sledge was set up as a sea ice drilling platform, with hydrographic winch, drill and drill mast, grab, fuel and tools. The second sledge carried the NZ-1 wannigan, which is fitted with bunks, table, desk and small kitchen. This was used as a laboratory for mixing preservative for the sediment samples, as a dry lab for the IBM PC, used for programming and interrogating the S4 current meter, and as a kitchen and working area. The third sledge carried the remaining cargo, such as tents, personal baggage, the Grizzly when not in use, further fuel and miscellaneous cargo. A VUW ski trailer for use with the Grizzly was towed last.

D3B LGP operation

The towed load for the D3 was quite high as indicated by the necessity to remain in 2nd gear on soft dry-cold snow in the area from Ross Island to the McMurdo Ice Shelf. We estimate that each Cantago sledge with cargo had a dead weight of about 5 ton giving a total dead weight of 15 ton. There was no method available to measure draw bar pull directly, however, this was estimated from published D3 performance curves to be about 8000 lbs (35 kN) on soft snow in 2nd gear, reducing to about 3000 lbs (15 kN) in 3rd gear on thin snow-smooth sea ice. This would seem to be a sensible maximum load for long distance travel when a variety of surface conditions are encountered. The D3 performed very satisfactorily with only a few minor problems. The ether cold start facility was required at temperatures below −5°C and the batteries require heating below −15° to −12°C. A Herman Nelson heater should be considered a necessary accessory for the D3 when in the field, especially in the October-November period. A field rescue kit consisting of 2 heavy duty snatch blocks, chain and materials to make a deadman anchor should also accompany any bulldozer while in the field. This was not required by us this season but recent experience has highlighted the advantage of such equipment.

We had minor problems with clogging of the primary fuel filter which is in a different priming pump configuration than shown in the operator's manual. Perhaps a manually operated priming pump should be used in Antarctic conditions. There was also a leaky engine seal which required regular additions of oil. The loss of oil however decreased as the atmospheric temperature increased and as the engine accumulated more operating hours. The winch-wind wire became damaged while extracting the D5 on 1 November. This problem reoccurred in New Harbour and required cutting the winch wire and enlarging pan of the gap between winch drum and cheek to remove the crushed page 22 wire. A new wire was provided later in the season. The gap between winch drum and cheek should be reduced because the problem will easily reoccur.

A running log for the D3 is shown in table 1 with an analysis of fuel consumption for varying conditions.

Cantago sledges

Several of the older ski shells on these sledges require replacement as the keels have been worn through. The draw bars and rear ski connecting bar should also be raised to give better ground clearance, as on the newer sledges and USARP sledges.

NZ-1 wannigan

The wannigan proved to be very useful for our laboratory, kitchen and eating area and is well fitted out. The following improvements are suggested to increase the NZ-1 versatility.

(i)Permanently fixed aluminium ladder to give safe access to roof aerials.
(ii)Small step ladder for safe access to door when on sledge.
(iii)Increase solar panels to enable faster charging of VHF nicad batteries.
(ib)Electrical noise suppression from generator when radios in use.
(v)Mini vacuum cleaner (eg 12 v) to clean dust and clothing fluff in lab environment.
(vi)The "fridge" could be improved by removing from wall and installing through the floor. Its sharp corners at head height are dangerous.
(vii)Hermetically sealed double glazed skylight.
(viii)12 volt internal wiring to attach to generator.

Grizzly toboggan (G4)

This toboggan was used generally for short distances (bathymetry and route finding) and travelled for much of the time on the third Cantago sledge to keep the distance travelled to a minimum. The machine performed satisfactorily with adjustments required to the chain drive gear box and twin carburettor, which are more difficult to tune than the standard engine.

Helicopter operations

Four hours helo time was used for a sea ice reconnaissance to Tripp Bay. The route expected to be taken by the D3 was flown to make a map of ice conditions. Two ice crack monitoring stations at Depot Island and C. Roberts were also established during this flight. The helo reconnaissance proved to be extremely valuable and the route map used extensively. We recommend that similar flights should be made for future tractor trains.

page 23

Event Diary

14 Oct. G. Blake arrive Scott Base.
14-24 Oct. G. Blake preparing equipment for K042. Attended survival course.
24 Oct. A.R. Pyne and B.L. Ward arrive Scott Base (3 day weather delay in Christchurch).
25 Oct. Unpacking cargo. G. Blake drove D3 and NZ-1 to ice edge for Scott Base recreation trip. Equadorian guest scientist Fernando Zurita arrives Scott Base.
26 Oct. Began setup of drilling equipment on sledge (winch and hydraulic unit and drilling mast). Cleaned up NZ-1 after Sunday trip. Pyne, Ward, Zurita attend evening survival lecture.
27 Oct. Helo reconn. of sea ice to Tripp bay. (Pyne, Ward, Blake, Ayres and Saxby). Established ice crack monitoring stations at C. Roberts and Depot Island. Zurita attend survival course, joined by Pyne and Ward in late afternoon.
28 Oct. Continue equipment preparation. B. Armstrong and P. Shane arrive Scott Base.
29 Oct. Survey work at Erebus Ice Tongue to locate S216 sediment trap. DOSLI surveyors (Anderson, Faloon) and K042 personnel. Test of K042 Grizzley (G4). Armstrong and Shane attend evening survival lecture.
30-31 Oct. Armstrong and Shane attend survival course. Continue preparation of equipment. Meeting with S216, Surveyors and K042 at Scott Base to discuss respective programmes and cooperation for the season.
1 Nov. Preparing equipment in morning. Pyne and Blake take D3 and rescue equipment to Erebus Ice Tongue for D5 rescue.
2 Nov. Continue equipment preparation including adjustment of G4.
3 Nov. Final packing sledges and equipment. Tested drill sledge equipment and grab in front of Scott Base in afternoon. Pyne and Zurita tested S4 current meter in fish hut. Tractor train departed Scott Base at 10.30 p.m. Spent night on sea ice near runway.
4 Nov. Continue travel towards tip of Dirty Ice. Met K191 near sea ice edge to discuss route and ice conditions. Arrive Butter Point 2.30 a.m. 5 Nov.
5 Nov. Leave two NZARP survival boxes at Butter Point. Pick up explosives. Continue to Explorers Cove, New Harbour, arrive 9.00 p.m. Winch wire jammed in drum on D3.
6 Nov. Visit S043 (diving group, SCRIPPS) to discuss local sea floor topography and ice conditions. Bathymetry survey of proposed sample line.page 24
7 Nov. Stan 87-1 sample site. Drilling access holes and taking grab samples. Ward sprains ankle. Zurita picked up by helo 2.00 p.m. to return Scott Base.
8 Nov. G4 used by Pyne and Shane to locate route to 100 m sample site (87-1-6). Echo sounder repaired in afternoon. Last sample for Explorers Cove taken.
9 Nov. Depart Explorers Cove 1000 hours. Arrive Cape Bernacchi 1700. Samples put into preservative. Echo sounder soldered by Blake.
10 Nov. Blake checking sample line route with D3. Armstrong and Shane do bathymetry survey with G4. Pyne and Ward set up IBM PC and test S4 compass. In afternoon start grab sampling on surveyed line (87-2).
11 Nov. Bathymetry survey completed. Two final sites grab sampled. Ward and Armstrong mix batch of preservative, preserve sediment samples. Blake reorganizes gear sledge. S4 current meter profile taken twice at 87-2-6 (108 m) site, for comparison of data. S216 arrive 1930 hours.
12 Nov. Depart Cape Bernacchi 1030 hours. S216 remain to core sea floor. 1645-1700 at Marble Point, load 6 fuel drums. Depart Marble Point 1735 hours. Arrive Spike Cape 2250 hours. Unload K121 penguin tracking hut. Pyne blasts hole in 44 gal drum, to leave with one other.
13 Nov. Depart Spike Cape 1000 hours. Travel over rough ice. Pass Dunlop Island 1200 hours. Pyne and Blake change oil filter in D3, 1700 hours, just south of Cape Roberts. Still having problems. Blake discusses problem with Clayton Ross, Scott Base mechanic, 1900 hours. Changed another oil filter. Proceed at 2030 hours through very rough ice to Cape Roberts. Continue around point to smoother ice, arrive 2225 p.m.
14 Nov. Helos behind schedule, proposed VIP visit uncertain. Scott Base 'flu hampering operations. Request relayed for resupply via K191 (Surveyors). Bathymetry survey carried out. Drill four holes (87-3) and take grab samples.
15 Nov. S216 arrives with sampling equipment provided by Dr. E. Barrera, Ohio State University; pH meter non-functional, mercuric oxide containers (glass) broken. Disposed of contaminated material by burning. Finished sediment sampling. Pyne took two current profiles at 100 m site. Camped third night at Cape Roberts.
16 Nov. Current profiling in central deep (800 m) basin in Granite Harbour. S216 arrive 1700 hours with mail, new pH meter.
17 Nov. Depart for inner Granite Harbour 0935 hours. Took water profile with S4 off Couloir Cliffs. S216 coring nearby. Depart 1430 hours for page 25 Mackay Glacier Tongue snout. Put S4 down at 705 m for overnight profile. Camped near S216.
18 Nov. Retrieve S4 after 15.3 hour profile near sea floor. Moved camp to Cuff Cape, on south side of Mackay Glacier Tongue. Set S4 to profile overnight in 152 m water. S216 still coring in area.
19 Nov. Retrieve S4 0900 hours. Depart Granite Harbour 1045 hours. S216 remain to continue coring. K042 continue north, crossing two cracks, traveling on outside of large bergs, arrive Tripp Island 2400 hours.
20 Nov. Pyne, Ward, Armstrong and Shane carry out bathymetric survey for sampling line. Blake checking Herman Nelson operation. S216 arrive 2100 hours.
21 Nov. Sampled Tripp Island grab transect (87-4-1 to 7). S216 continue areal bathymetric survey for Tripp Bay area. K191 survey flagged sites.
22 Nov. Ward, Armstrong and Shane take bathymetric survey in tide crack. Blake and Pyne start S4 profile and water sampling on grab line. Echo sounder freezing up during use. In afternoon, Armstrong, Blake and Shane take G4 to fry Glacier Tongue to continue areal bathymetric survey. Pyne and Ward finish S4 profiling. Ward mixes batch of formalyn. Camp with K191 and S216.
23 Nov. Travel to Gregory Inland. K191 continue survey at Tripp Bay, S216 depart for Granite Harbour. Arrive Gregory Island 1635 hours. Pyne and Shane do bathymetric survey.
24 Nov. Sample grab transect 87-5. Take S4 current profile. K191 arrive 2000 hours. Ward preserved sediment samples.
25 Nov. Retrieve S4. Ward and Armstrong mix formalyn. Shane packs gear, tents. Blake and Pyne straighten wannigan sledge towbar. Depart 1320 for Granite Harbour. Arrive 1800 hours. S216 coring nearby. Set up S4 for overnight current profile at 858 m. Brake system on S4 slipped at 0520 hours on 26th. Reset and continue profiling.
26 Nov. Thanksgiving Day. S216 departs for Dunlop Island. K042 travels to Cape Roberts, arriving 1630 hours. Pyne, Blake, Shane and K191 clean junk from C. Roberts hut, for retro to Scott Base. Thanksgiving Dinner with K191.
27 Nov. Depart Cape Roberts 1000 hours, arrive Dunlop Island 1500 hours. Bathymetric survey of grab transect completed.
28 Nov. Started grab transect 0930 hours (87-61 to 6). Put S4 current meter down for profile. VIP helo dropped off mail about 1400 hours. Returned 1 hr later for 45 min visit (Ruth Richardson, Jim Barker and page 26 co.). Showed them samples, biota, and S4 results. Put S4 down for overnight profile.
29 Nov. Ward and Armstrong check all preserved samples for pH reading, and adjust (0945-1745 hours). Blake and Shane retrieve S4 and sledge from 87-6-6 site.
30 Nov. Depart Dunlop Island for fuel stop at Marble Point. Met S-216-seconded Armstrong to S-216 to assist in setting sediment traps. Received spark plugs from helicopter, sent out mail. K042 pick up l barrel Mogas at Marble Point, continue to large iceberg in New Harbour, arrive 2220 hours.
1 Dec. Pyne, Blake, Shane drill one access hole (87-1-8, 164 m) take grab sample, set S4 for 24 hour profile. Armstrong still with S216, who have mechanical breakdown of transport at Marble Point. Pyne, Blake, Shane take G4 to Butter Point to dispose of old explosives. Ward prepares batch of formalyn, preserves sediment samples.
2 Dec. S216 still at Marble Point with mechanical problems. Ward and Pyne preserve samples, check pH of formalyn mix.
Retrieve S4 current meter at 1400 hours. Tried 3 profiles through water column; considerable distortion in data.
Met two Greenpeace personnel touring New Harbour on toboggan.
3 Dec. Pyne retrieves Armstrong from S216 with G4. S216 mobile. Ward, Blake, Shane continue with D3 train to Cape Chocolate. Armstrong and Pyne catch up 1315 hours. S216 passed K042 at 1400 hours. Continue to Cape Chocolate, crossing several large cracks. Pyne and Shane scout route in G4 toboggan. Cape Chocolate inaccessible. Deviate to Blue Glacier. S216 arrive 2050 hours. Leave Cape Chocolate survival box at Blue Glacier.
4 Dec. Pyne and Shane do bathymetric survey for grab transect. Grabs completed 1800 hours. K191 arrive 1930 hours. Set S4 for 12 hr profile at 87-7-7, 107 m, overnight. Armstrong and Ward preserve samples.
5 Dec. K191 remains at Blue Glacier site to wait for helo and S-216 (Dunbar) for survey of sediment trap sites. Ward and Armstrong drive ASV (K191 vehicle) back to Scott Base, departing 1100 hours. Blake drives D3, Shane and Pyne scout route with G4 toboggan. VIP helo (Holborow, Suggate, Taylor) buzz our caravan, do not stop. Helo arrives for K191. K042 continues past Dirty Ice to Scott Base, arriving 2040 p.m.page 27
6 Dec. Depart SB for Cape Armttage transect 1045 hours. Bathymetric survey completed and flagged sample sites. Ward and Armstrong mix formalyn.
Cleaning of wannigan started. Final discussions with S216 at McMurdo Station.
7 Dec. Grab transect at Cape Armitage (87-8-1 to 6) completed at 1630 hours. Water samples for Dr Barrera taken. Cleaning continues.
8 Dec. Cleaning and sorting of gear continued. Blake and Pyne unloading sledges. Shane to McMurdo Sick Bay with fever and dehydration. 1900 hours back to final grab site (87-8-6) to demonstrate operation to VIP party (Holborow, Suggate, Taylor) and TVNZ film crew.
9 Dec. Finish packing sediment samples. Retro cargo packed for shipment (air) to NZ. Sledges unloaded, field gear returned.
10 Dec. Armstrong and Shane depart for NZ.
11 Dec. Blake and Pyne assist S216 (Dunbar) to set sed trap at Erebus ice Tongue. Ward takes K042 cargo and baggage to Hill Cargo, finishes personal packing.
12 Dec. Ward and Pyne depart for NZ.
14 Dec. Blake departs for NZ.

Field Equipment

20-person day food boxes:

The improvements made in field rations are commendable. The availability of packets of frozen vegetables, roasts, chops and bacon was most appreciated. Comments on quantities, etc. were made on the form filled out for the field Store Person before leaving Scott Base.

We do feel the organisation of the food boxes could be standardised further. The food boxes should include staples, such as flour (not just self-rising), toilet rolls and paper towels. The only items to be obtained separately should be perishables, such as cheese, salami, frozen meat and vegetables.

"Fin" Ice Augur

A new "Fin" 4" diameter hand operated ice auger was used extensively by K042 this season. It is a fast efficient way of drilling holes to test ice thickness and therefore especially useful for the D3 operation. The drill was also used for bathymetry surveys to make a hole for the echo sounder transducer. The drill should be available for future tractor trains; however, some care and skill is required for efficient operation. Good quality files, sharpening stone and adequate instruction is necessary to keep the drill razor sharp and operating properly.

page 28

Survival Boxes

Three large red survival boxes were carried by the tractor train and were deployed at Butter Pt Hut, Cape Roberts Hut and on the south side of Blue Glacier for helo lift to C. Chocolate. In addition, old food caches were returned to Scott Base from the C. Roberts trig site and Butter Pt. huts. A food cache in old NZARP 20 man day cardboard [unclear: boxes in the Commonwealth Stream John] in Explorers Cove was pointed out to us by Bill Stockton (S043), but we were unable to retro it to Scott Base.

K121 Penguin Tracking Facility (toilet)

A small dismantled hut (toilet) was carried by the tractor train to Spike Cape where it was offloaded for K121 and later helo-lifted to Hanson Ridge. This could have been better organised at Scott Base, as we understand no fasteners were supplied to erect the hut. Two empty 44 gal fuel drums were also supplied by K042 with tops removed by plastic explosives, for anchoring the hut on Hanson Ridge.

Radio Communications

A Codan SSB installed in NZ-1 and 2 Tait VHF radios were used this season. This combination of radio systems was generally very satisfying with the VHF radios giving us flexibility for surveying and route finding. Some minor problems were noted and these are listed below for future consideration.

(i)Some of the Tait VHF batteries are tired and could not be charged from a solar panel and would not hold the charge even when a generator was used.
(ii)NZ-1 wannigan requires a greater solar panel charging capacity (see NZ-1 in the field transport section).
(iii)The VHF system repeater at Mt. Newall has some unexpected blind spots such as close along the coast from Spike Cape. It is also obscured in much of Granite Harbour and north of Cape Ross as expected.
(iv)The surveyors (K191) used high gain aerials on the VHF radios which improved performance, especially over long distances without elevation, eg sea ice. These aerials are light in weight and very useful for our sea ice work.

On 2 or 3 occasions we travelled late into the night and could not contact Scott Base after stopping between 0100-0300 hours. We had understood Scott Base was operating a 24 hour radio watch and we felt unfairly criticised when we did not respond to the 0800 hours schedule. There seemed to be some breakdown in communication between the radio operators' and field operators' organisation at Scott Base.

page 29

Refuge Huts

Cape Roberts

The area around the C. Roberts hut was cleared of redundant equipment stored during previous VUWAE-K042 visits in 1982-1984. All this equipment was returned to Scott Base for disposal or return to NZ.

Butter Point

Explosives remaining at Butter Pt. from the CIROS programme were destroyed as per request from Ant. Div. Building and Services Officer. A small quantity of explosives was returned to the NZARP magazine after this season's field programme.

Garbage Disposal

A 44 gal. drum incinerator was made in the field to burn flammable and metal wastes on the sea ice. The incinerator in conjunction with some fuel gave a clean smokeless burn which reduced to non-burnable materials which were returned in the drum to Scott Base for disposal. Human and biodegradable waste were released into the sea.

page 30
Table 1. D3B Running Log
Date Location Distance Running hours Fuel (Diesel) Engine Comments
Nov 3 Scott Base-Ice Shelf 12 km 2.5 20% 0.51 Snow cover, 2nd gear only
4 Ice Shelf-Butter Point 60 km 14.0 150% 2.51 3rd gear
5 Butter Pt.-Explorers Cove 20 km 5.0 50% 1.01 2nd gear, snow and multiyear ice
6 Explorers Cove - - - -
7 Explorers Cove sampling 3km 2.0 20% - Short run and idling
8 Explorers Cove sampling 5 km 2.0 10% 0.51 Short run and idling
9 Explorers Cv-C.Bernacchi 15 km 6.0 100% 0.51 2nd gear, heavy snow & multiyear ice
10 C.Beniacchi sampling 10 km 3.0 30% - Blading & pushing snow on transact line
11 C.Bernacchi sampling 3km 3.0 25% - Idling
12 C.Bernacchi-Spike Cape 25 km 14.0 80% 0.51 Snow & multiyear ice at Bernacchi Bay 4 hours idling at Marble Pt. fuel pickup
13 Spike Cape-Cape Roberts 35 km 10.0 80% 0.51 3rd gear, thin snow cover, smooth ice
14 C. Roberts sampling 2km 2.0 15% - Idling
15 C. Roberts sampling 4 km 1.0 10% - Idling
16 C.Rbts-Cent.G.H.-C.Rbts 25 km 4.0 40% - 3rd gear, 2 sledges only, smooth ice, snow cover
17 C. Roberts-Mackay G1. 20 km 6.0 50% 0.51 3rd gear, smooth ice & snow
18 Mackay G1.-Cuff Cape 8 km 2.0 20% - 3rd gear, smooth ice, no snow
19 Cuff Cape-Tripp Island 54 km 14.0 140% K01 3rd gear, smooth ice & snow cover
20 Tripp Island - - - -
21 Tripp Island sampling 3 km 8.5 15% - Idling
22 Tripp Island sampling 5 km 4.0 15% - Idling
23 Tripp Is.-Gregory Island 15 km 4.0 45% - 3rd gear
24 Gregory Island sampling 4km 6.0 20% - Idling
25 Gregory Is.-Centrat G.H. 15 km 4.0 H0% 0.51 3rd gears no w cover, small area rough ice
26 Central G.H.-C.Rbts 10 km 2.0 20% -
27 C.Roberts-Dunlop Is. 25 km 5.0 45% 0,51 3rd gear, good travel on snow ice
28 Dunlop Island sampling 3 km 6.0 20% - Idling
29 Dunlop Island - - - -
30 Dunlop Is.-New Harbour 45 km 10.0 95% - 2nd & 3rd gear. Multiyear ice Bernacchi Bay-New Harbour
Dec 1 New Harbour - - - - -
2 New Harbour - - - - -
3 New arbour-Blue G1. 40 km 8.0 80% 0.51 3rd gear, smooth ice, little snow
4 Blue G1. sampling 6 km 6.0 15% - Idling
5 Blue G1.-Scott Base 60 km 10.0 105% 0,51 3rd gear, bare ice & fast warm snow
6 C. Armitage 6 km 5.0 20% -
7 C. Armitage 6 km 8.0 20% -
8 C. Armitage 6 km 3.0 20% -
Totals 550 km 180.0 1455% 8.51
370 gal

Analysis of running log gives the following indications of performance for different conditions lowing near maximum suggested load.

Condition Transmission Fuel Consumption SPEED
Soft thick snow on rough (blocky) ice 2nd 16% per hour:6.7% per km 2.5 hour
Soft thick snow, smooth surface 2nd 13.6% per hour:4.7% per km 3 km per hour
Hard, thin snow/sea ice 3rd 10.5% per hour:2.6% per km est 5-7 km per hour
Fast warm snow/bare sea ice 3rd 10.3% per hour:2% per km 6 km/hour

In exception conditions on warm (wet) sea ice the D3 and sledges were measures travelling at 12-14 km per hour with the ASV speedo. For general planning in good surface conditions we suggest using an expected fuel consumption of 12% per hour:3.5% per km and speed between 5-7 km per hour.