ASSESSMENT OF SNO-TRIC MOTOR TOBOGGANS
Two near-new Snow-tric motor toboggans were provided by Antarctic Division to the VUWAE 15 party at Horseshoe Mountains as a substitute for the Polaris toboggans disabled in the Skelton Neve. The Sno-trics were used in the Darwin Mountains also, along with one Polaris toboggan. One Sno-tric was powered by the original Sachs 2-cycle 18 HP engine; the other had been modified for a Kohler 4-cycle 10 HP engine, which is standard on the Polaris toboggan. The Sachs Sno-tric received the most use, despite the inconvenience of petrol fuel. The Kohler Sno-tric felt underpowered for slopes and hauling heavy loads, and it had a marked propensity for burning out the clutch. However most of the comments that follow apply to the Kohler Sno-tric as well as the Sachs Sno-tric. A total of 340 miles was covered on the latter, 100 of them with a moderate to heavy load (500 to 1000 lbs) in tow. Because the Sno-tric was intended as a replacement for the Polaris the performances of the two machines were compared in a detailed report by Barrett to Antarctic Division (26 February 1971). The report's summary is given below:-
The Sno-tric is not a suitable replacement for the Polaris. It is of much lighter construction, and cannot cope as well as the Polaris with the variety of snow and ice surfaces and slopes normally encountered in the Transantarctic Mountains. The hard steering, the less responsive motor and gear system, the poorer traction on hard surfaces, and the difficulty in getting a sled moving, make it unsuitable for towing heavy loads. The change to the Kohler engine improves the toboggan's starting capability slightly, but at the expense of the clutch. Even with modification the Sno-tric would be much less safe than a Polaris in a crevassed area.
The Sno-tric seems best suited for day trips up to 15 miles from a base camp, and for towing a light sled (up to 600 lbs) on moderate to good surfaces. A toboggan with performance comparable with the Polaris must be found if the NZARP geological programme is not to be much more limited in scope in the future.