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Victoria University Antarctic Research Expedition Science and Logistics Reports 1977-78: VUWAE 22

A. Transport

A. Transport

(a) Toboggans Event 12

Using two OMC two-stroke toboggans (NZARP No. 23 and 25) Event 12 suffered only minor mechanical failures. Toboggan 23 was used for all but 3 weeks of the 3 month field season on the Taylor Glacier. Toboggan 25 was used for the initial survey trip from the snout to Depot Nunatak, where it was handed over to Event 13 for their travel downglacier. Full accounts of mechanical repairs and problems are listed below:

NZARP 23 OMC

Scott Base
23-31 Oct Minor repairs and familiarisation of toboggans. Repaired pull-start cord and broken drive-chain during field testing of equipment.
Taylor Glacier
4 Nov Locking nut on end of flywheel and primary clutch sheave coming loose.
10 Locking nut still coming loose. Scott Base sending out new one on next resupply
28 Left hand idle spring replaced
29 General toboggan maintenance and tuning
1 Dec Replaced shoulder for leaf spring left ski and one right hand idle spring.
5 Left hand idle spring replaced. Changed primary sheave locking nut and flange. Took slack out of drive-chain. Clean and check plug gaps.
16 Toboggan running rough, seems like fuel starving.
8 Jan Replaced fuel pump, still rough.
12 Replaced pull-start recoil spring. Still poor carburettion, but no solution.
17 Primary sheave clutch spring broken, temporary repairs.
18 Base mechanic did check of toboggan. Points, advance and retard, fuel mixture all checked. Replaced primary clutch assembly. Still not running well underload and when warmed up.
21 Both rear swinging arms and bearings replaced.
page 12

NZARP 25 OMC Event 12

Scott Base
23-31 Oct Minor repairs and familiarisation. Idling problems.
Taylor Glacier
3 Nov Adjustment to mixture, due to lean running.
6 Carburettion problems. No ratchet grip on pull-start, reset and tighten mounting.
10 Changed spark plugs, just flooding.
20 Still idling problems.
21 Handed toboggan over to Event 13.

Estimated mileage for OMC 23 600-640 kilometers, during which time the major problem was poor carburettion. All other repairs were minor, except for the two rear swing arms. The failure of this back suspension resulted from the wear and consequent loosening of a locking sleeve on the left hand side of the rear axle. This allowed the axle to twist and pull out of the left hand bearing and swinging arm mounting. The right hand swinging arm snapped away from the toboggan body thus allowing the whole rear axle assembly to break loose, bringing the toboggan to an immediate stop.

(a) Toboggans Event 13

Three OMC 2 stroke toboggans (NZARP Nos. 22, 24 and 25) were used. Number 25 was used on the Taylor Glacier, the other two on the coastal trip to Cape Royds. Only minor problems were encountered, which were not sufficient to cause any delays. Pull start chords were replaced after breaking on all three machines. Also none of the machines idled satisfactorily. Starting difficulties were experienced particularly with Nos. 22 and 25 until the temperaments of the individual machines had been determined. A new throttle cable was fitted to No. 22 after breaking at Cape Evans. No. 25 proved particularly difficult to start on a number of occasions, the problem being a faulty primer pump which necessitated detaching the primer hose and sealing with a finger until sufficient suction to draw fuel was established. This machine was also used without neutral lockout after failure of a lock washer and subsequent clutch failure while Event 12 had the machine. The non-availability of spare clutch parts when we went into the field meant this fault could not be repaired.

Fortunately no track and suspension problems were experienced, no springs were broken. This was probably due to good advice we received on loading the sledges and not the toboggans. In general only the driver travelled on the toboggan. Oh smooth glacier ice travelling page 13 up inclines where more traction was needed, an extra person travelled on the toboggan. Because very low speeds were used on the Taylor Glacier, spark-plugs oiled up rapidly and needed regular cleaning/replacement. Because of this and the poor idling characteristics it was difficult to maintain a slow regular speed, which could only be achieved by constantly working the throttle. The entire trip was downhill from Depot Nunatak to the snout apart from short excursions to the Beacon and Pearse tongues of the glacier. Thus it was possible to haul two sledges with a total load of up to 1400 lb. Control was improved considerably by shortening the tow lines between sledges and between the toboggan and sledges to minimise fish-tailing. Ice clots were very necessary in these conditions.

A petrol allowance of 8 mpg proved more than adequate particularly on the Taylor where most of the travel was slow and downhill. A toboggan cover was used on the Taylor Glacier to keep snow etc. out of the stationary toboggan. This performed satisfactorily although only moderate winds and light snow falls were experienced. Covers were not available for the Cape Royds trip. One modification which proved useful was the fitting of a rear-vision mirror to No. 24. This avoided the problem of turning to check on the load being towed when wearing heavy down gear.

The toboggans we used performed satisfactorily with no major difficulties, a large factor in this was probably the thorough checking and tuning they received at Scott Base before departure from Jos Lang and Barry Hiscock.

(b) Sledges

Event 12 went into the field with two sledges (1 dog sledge and one of the new 'red' sledges). Both withstood the conditions exceptionally well. The red sledge was handed over to Event 13 on Nov 20 at Depot Nunatak. Minor repairs had to be made to this sledge. Twine lashing and doping of a split outside longitudinal, which was damaged during a downslope manoevre on extremely smooth ice. The sledge and toboggan were going directly down a low gradient slope. The driver turned slightly causing the sledge to swing out catching up with the toboggan and eventually hitting a small snow patch and 'broadsiding' over. The sledge was fully laden and had a brake-man. Unfortunately, because this sledge lacked dog sledge handles and stand, braking by the brake-man proved ineffective against this rapid swinging out motion.

Other damage was minor (a) one leather lashing between the first bridge and runner was replaced; (b) abrasion of front cow-catchers, resulting from contact with the toboggan.

The sledge tanks appeared to have canvas sidings of poor quality. The dog sledge siding canvas continually ripped along eyelet holes and hook rivets. This was simply the result of badly deteriorated canvas. However, the red sledge had a new sledge tank and canvas sidings. This too ripped at the eyelet holes, on inspection these sidings did not have extra strengthening along the margin. Canvas siding failure was due to age and poor manufacture. Repairs seemed impractical, further ripping was prevented by loosely tying the canvas sidings, when loading, and increasing the main sledge lashings.

page 14

Event 13

One dog sledge and one combination Nansen sledge were used on the Royds trip. Both had sledge tanks. No problems or breakages occurred. The same dog sled was taken into the Taylor, no transport difficulties were experienced in helicopter loading despite the difficulty in keeping the sledge runner away from the lugs projecting below the helo cabin, and keeping the handlebars clear of the ground when landing. At Depot Nunatak we also obtained the red sledge with the brake from Event 12. The dog sledge had both brake and keels although the keels were not used on the hard glacier ice.

The only repairs necessary were to replace the lashings and straighten and lighten the bolts on the brake bars. Brakes received extensive use because of the amount of downhill travel. Rope brakes fitted on the rear sledge were used for brief spells but have a very short life and were conserved carefully. Sled tanks were used with both sledges, one required the patching of a tear at the Beacon Valley.

(c) Air transport to, from and in the field was provided by U.S. Navy helicopter.