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

McMurdo Sound Studies (K5)

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McMurdo Sound Studies (K5).

NARRATIVE:

Pyne and Cattley arrived at Scott Base on October 16, four days behind schedule, due to a hold on flying because of communication problems caused by sunspot activity. The first three days were spent servicing the IH-500 tractor, work that had not been anticipated. The refitting of the Wannigan for scientific use had been started by the winter over personnel but was unsuitable and was removed. The base carpenter, Pyne and Cattley spent a full week refitting and securing the Wannigan to the sledge. By the time this work was complete we were a full week behind in our planned schedule.

The remaining preparatory work which included issuing and testing the normal field equipment and testing our scientific equipment was therefore rushed. We had allocated three to four days for testing the scientific equipment alone, but this became impossible and consequently we decided to leave for the field with some equipment untested. In retrospect we were lucky that only one major item of equipment (the underwater camera) did not work because of this.

On November 4 Pyne, Ward and Cattley (K5) departed Scott Base at 0950 hrs. for Cape Royds. At 1800 hrs. we reached Cape Evans and remained there for the night. Numerous thin snow drifts between the Erebus Ice Tongue and Cape Evans slowed us down considerably. The following day we completed the traverse to Cape Royds. During this leg of the trip, we became stuck in deep soft snow out from the Barne Glacier.

On November 6 we prepared the sampling equipment for a coring attempt in 850m deep water 10km northwest of Cape Royds. This involved adding 400m of extra wire onto the winch and transferring all the equipment onto the toboggan-pulled Tamworth sledge. This was necessary because we anticipated that the ice would be thinner out towards the centre of McMurdo Sound. We were not prepared to risk the heavier tractor and sledge with Wannigan without first checking the ice thickness. As it transpired the ice thickness at the sample site was 1.2m and sufficient to carry the tractor. The next two days were spent in actual collection of the sample, cleaning and repairing the equipment and preparing to begin the "across sound" traverse.

On November 9 we departed Cape Royds for a rendezvous at Cape Evans with the dog team carrying our mogas resupply and the penguin census group, Colin Monteath and Lindsay Main, who joined us for three days at Cape Evans.

Between November 10-16 we traversed a line westwards between Cape Evans and the Strand Moraines to continue the sea-floor sampling programme. On November 12 Brent Alloway joined us and Monteath and Main left on the same helicopter for the Wright Valley. Peter Barrett joined K5 on the 13th. K-2 (Lands and Survey surveyors) joined us on the 16th for one night before continuing to Butter Point, we obtained cores 2 through 10, 5A and 8A along this line, arriving at the Strand Moraines on the 16th.

By this tune we needed a resupply, and repairs to the IH-500 and toboggan. On the 17th, Cattley, Pyne and Ward drove back to Scott Base to institute repairs and manufacture replacement weights for the sphincter corer. We spent 4 1/2 days at Scott Base, leaving there at 4.30 p.m. on the 22nd, and arriving at the Strand Moraine camp at 10.30 p.m. During this time, Barrett and Alloway recorded tidal measurements and attempted several core and grab samples. Sample #11 was taken by orange-peel grab during this time.

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November 23 and 24 were spent travelling the 85km to Cape Roberts. On the 24th Barrett and Pyne took the toboggan back to Butter Point to assist K-2 (surveyors) in the sea ice movement survey, but were able to rejoin us that evening at Cape Roberts. The following day we began the Granite Harbour sampling programme. Three cores (12 through 14A) were taken along a line extending from Cape Roberts to Cape Archer. On the 29th and 30th cores 15 and 16 were taken within Granite Harbour. On Tuesday, 1 December, Barrett was lifted out by helicopter for his return to Christchurch, and Paul Fitzgerald joined us. The 2nd was spent travelling out of Granite Harbour to Cape Roberts. On the next day, the Tamworth sledge and toboggan were loaded with the sampling equipment, as the IH-500 and Wannigan could not cross the 2 1/2m lead 1km seaward of Cape Roberts, and Pyne, Cattley, Fitzgerald and Alloway travelled 5km offshore for core 17. We then moved to Dunlop Island after picking up fuel at Cape Roberts.

On the 4th we moved from Dunlop Island to Marble Point, where two full fuel drums were stockpiled on the land. That evening while still at Marble Pt. we received a radio broadcast from the O.I.C. Scott Base for all Kiwi field parties in the McMurdo area. The message required that all field programmes be prepared to move all personnel and essential equipment back to Scott Base as soon as possible. No clear statement explaining why this was necessary was given but "the inability to support science field parties from McMurdo Station" was quoted. A final decision about the withdrawal of field parties and Vanda personnel would be made on the Sunday evening (December 6) by the O.I.C.

We decided to continue to Butter Point that evening to meet the K2 surveyors. Because of the broadcast we were all committed to returning to Scott Base with K2. Originally we had intended to send only the togoggan back to base to bring back a part needed for the tractor so that the work at Cape Chocolate could be cone. The next day before leaving for Scott Base we successfully sampled in front of the Ferrar Glacier snout (core 18).

If we had been told that the problem of support concerned only helicopters (from which we were independent) our original intention to move to Cape Chocolate would have been possible. The Sunday decision which required us to return to base but to finish work that was enroute came too late.

December 8 to 14 were spent cleaning and returning gear, packing cargons and samples for transport to New Zealand, as well as preparing equipment for Pyne, Fitzgerald, Alloway and Lindsay Main to take to Mt. Feather.

We had hoped to complete the sampling programme at Cape Chocolate by togoggan. Unfortunately the only other toboggan available at Scott Base was an old OMC which was considered unreliable for a journey of this length. The total equipment load was over 2500 lbs, and was considered too great for our single toboggan to pull, so this part of the programme remained uncompleted.

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.

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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.

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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.

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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.

WEATHER:

Poor weather conditions were experienced early in the season (strong winds and snow with intermittent white-out for 3 days), but did not hinder progress of the sea-floor sediment sampling programme. Later in the season, we experienced exceptionally good weather at Granite Harbour and New Harbour. A summary of weather observations is presented in Appendix III.

COMMUNICATIONS:

A Compak radio was used for daily radio skeds with Scott Base. The equipment worked well but on many occasions there were operator problems at Scott Base. In particular messages from field parties often did not appear to reach the appropriate people at Base and was possibly the reason why some helo movements and resupplies did not go according to plan.

The availability of two VHF sets for the sea ice work would have reduced some problems and time delays. During this work the toboggan was often used for forward route reconnaissance and bathymetry traverses. With VHF sets it would have been possible to keep both toboggan and Wannigan informed of progress (or breakdown).

FIELD EQUIPMENT:

Clothing:

Several new items of clothing, the same models as the Antarctic Division issue, were first used by VUWAE members this season, and were all very successful. Minor problems were found with the bib-overalls which had some wear patches which were too small and too lightly sewn in stress areas. We also tried New Zealand manufactured wool felt booties in the normal Japanese mukluks. These booties are more expensive than the conventional mukluk inner boot but give superior warmth and ankle support.

Equipment:

See Transport section for report on the Antarctic Division "Cantago" sledge, IH-500 tractor and Snotric 047 toboggan.

Scientific Equipment:

This season the "sphincter corer" performed "with distinction", the triggering problem encountered last season having been eliminated with a new design. The poor penetration by the corer in some parts of the sound is definitely attributable to a hard gravelly sea floor. Even in this sediment short undisturbed cores were often retrieved.

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We are still learning how to operate the corer with successive attempts and minor accidents such as losing weights should be prevented in future.

The limitations of the winch which performed well last season were discovered this season. The extra lead weights on the corer and deeper water created a 600m depth limit to our operation even though there was sufficient cable for 1000m. unfortunately, testing the winch in deep water around New Zealand requires a large ship and great expense.

The underwater camera was the one major item of equipment which did not work successfully. The camera and flash components were borrowed from NZOI and mounted in our housing as in a previous season. Our unfamiliarity with the components and lack of time are probably the main reasons for the problems.

RECOMMENDATIONS:

Field Preparation:

The Narrative describes the considerable amount of work (some unexpected) necessary at Scott Base to prepare for a Tractor Train on the sea ice. The limiting factor to work on the sea ice is time, which is determined by when the ice is considered unsafe for heavy machinery, normally early-middle December. It is therefore imperative that the start to preparations at Scott Base be as early as possible to ensure sufficient field time to achieve a reasonable amount of work.

Transport:

The international Harvester 500 tractor performed faithfully this season. However, a larger tractor is really required for operation on the sea ice a considerable distance from Scott Base. A blade and winch are also necessary for some travelling conditions (see Transport section for details).

The "Cantago" sledge requires wider skis to improve its performance (see Transport section for detailed recommendations).

Communications:

Many problems which concerned field parties this season could have been avoided if one person only had been responsible for both helo logistics and radio scheds. The person who does the radio skeds is the most informed about field party movements and logically should be responsible for all Scott Base initiated field support (e.g. helo planning and resupply).

Portable radios (e.g. VHF) are needed for efficient work on the sea ice where parties must work some distance apart. This is particularly important for seismic work where people firing the charges require verbal communication with the recording station.

Equipment/Clothing:

A modification to the bib-overall design should be made to improve their wearability (see Equipment).