Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Victoria University Antarctic Research Expedition Science and Logistics Reports 1981-82: VUWAE 26

TRANSPORT:

TRANSPORT:

The International Harvester 500 crawler tractor and Snotric 047 motor toboggan were made available to Event 5 for work on the sea ice. The IH-500 tractor was used to pull the "Cantago" sledge with Wannigan and a Maudheim cargo sledge. The toboggan pulled a single Tamworth sledge.

Helicopter transport was used for an initial sea ice reconnaissance and fuel flight to Granite Harbour and later for minor resupply and personnel movements.

page 21

A detailed summary of performance and problems for each major transport unit is presented below:

IH-500 Tractor.

The tractor had been brought into the garage at Scott Base by the relieving mechanic and previous wintering mechanic for checking and overhaul. Two sheared main sub-frame studs and bolts had been discovered and one removed by October 16 when Pyne and Cattley arrived at Base. Three days were spent by Cattley and Pyne removing the remaining broken bolts, making new parts (which are not stocked for the tractor at Scott Base), reassembling and fixing the cracked fuel tank. The electrical system was checked and a new regulator fitted by the base assistant mechanic before leaving for the field on November 4.

The tractor started cold very well on most occasions, especially considering the cold temperatures in early November. Normal preheating and a small quantity of ether were usually all the starting preparation required. The "noyse" heater and parachute carried in case of starting problems were never required. There was a starting problem on only one occasion and this was found to be fuel leaking into the starter motor, gumming the brushes and contacts. No further starting problems occurred after cleaning the motor and sealing the holes in case of further fuel spills.

On November 10 a crack was discovered in a previously repaired section of the main frame. The crack slowly increased in length as we travelled across the sound to the Strand Moraines necessitating repairs before moving to Granite Harbour. It was decided that the repairs would be most easily carried out at Scott Base although the possibility of effecting repair in the field with helo support was considered. Repair of the frame required removing the old repair gusset and arc welding a new heavier plate steel gusset over the cracked section. The tractor returned to Scott Base on November 18 after completing the Cape Evans-strand Moraines sampling. The fuel tank sprang a further leak on returning to base.

The regulator was found to be faulty during the period at Granite Harbour. It was promptly disconnected and later repaired. The idler bearing for the fan belt became faulty on the return from Granite Harbour to Butter Point (December 4). The bearing was disassembled and regreased but remained faulty which necessitated a deliberately slow return to Scott Base.

Early in the season the tractor was using about 1 litre of transmission oil every eight running hours. A leak which contributed to higher oil usage was found at the oil guage connector and promptly fixed. The oil usage appeared to drop slightly later and averaged about 1 litre every 10 running hours. The track bearings were greased about every 3 running hours.

Minor repairs carried out in the field included replacing the clutch return spring and several battery retaining bolts broken by vibration during travel.

The IH-500 performed very well considering that it was usually towing between 13,000 and 14,000 lbs. and working at its limit. On several occasions the second sledge had to be disconnected when relatively minor obstacles were encountered because no reserve power was available. The lack of a blade on the tractor also meant that difficulty was experienced negotiating some rough ice or snow drifted areas. The difficulty of these situations would have been reduced considerably if a blade were available.

page 22

We believe that we were very lucky to cover over 800 miles with this machine considering it was underpowered and did not have a front blade. The great age of the machine and incomplete stock of parts at Scott Base reduce its suitability for this type of programme in the field. It is, however, very reliable and probably will be useful for several years yet around Scott Base.

Snotric 047.

This toboggan was new at the beginning of the 1981-82 season. The machine generally was easy to start and performed well with only two major problems.

Early in the season when temperatures were less than 10°C freezing often occurred in the original airfilter-carburettor system on the Briggs and Stratton engine. This usually happened after the machine had been idling or running slow for some time. It is thought that the carburettor remained sufficiently cold to freez out moisture from the air. The carburettor was dismantled several times and the ice scraped or melted out before the machine would start.

Secondly, the flexible exhaust coupling broke where it enters the muffler soon after leaving Scott Base. This did not affect the performance unduly but required that the toboggan be run with the fibreglass cowling removed until repairs were made at Scott Base.

"Cantago" sledge.

The "Cantago" sledge is a scaled down all steel version of the American tandam "Octago" sledge and was built in Christchurch for Antarctic Division DSIR. It was first used this season by Event 5 to carry a twelve foot long Wannigan, winch and fuel on the sea ice. The sledge performed reasonably well in most conditions and provides a form of transport not previously available from Scott Base. There were, however, some problems with the sledge which will require some modification.

The sledge did not perform well on the softer snow drifts, often breaking through to run on the sea ice beneath. Where the snow was more than 0.3m thick the sledge would bulldoze snow in front until the tractor would lose traction and stop.

PLATE III: Tractor and Wannigan at Cape Roberts.

PLATE III: Tractor and Wannigan at Cape Roberts.

page 23

The return from Granite Harbour to Butter Point involved crossing some rough ice around Cape Bernacchi. The rough ice caused some minor damage to the sledge in particular bending the small front ski protectors and slightly bending the draw bar.

The sledge was heavier at the stern with the Wannigan at the back of the deck. This, however, was necessary to maximise the remaining forward deck space for the winch and fuel.

We believe that the sledges performance could be improved if fitted with wider skis with a higher rocker in the front. This might be achieved by bolting wider ski shells underneath the present skis. By moving the back ski beam aft about 0.5m the loading capabilities of the sledge may also be improved.