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

Field Transport

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.