Since there was debate about whether the sledge could be used in their category III trek...
Found more info posted by WAB back in 2019:https://forum.dyatlovpass.com/index.php?topic=375.0
In this he says,
"And now it is necessary tell about theme of this section: Kolevatov device.
At first I should notice that Kolevatov was not the radio technician. Therefore no coils condensers and resistors were necessary for he. He studied on branch of nuclear physics. Radio engineerings were Woodpeckers, Kolmogorov and Doroshenko.
It is possible dream long on theme of "nuclear high-speed sledge», but all is much easier: Alexander Kolevatov tried make usual sledge of spare skis and available subjects. On them it is easier transport cargo, for example, backpacks. This craze of that period at all ski travellers. As experience of use of such devices yet was not, all moved ahead "trial and error method". Their big part was unsuccessful, therefore and has not been told in diaries of anything, besides joke seriously concerning the next failure.
On another there also could not be, because conditions of application this adaptation have not been considered. Always on deep snow sledge loses in efficiency of transportation. Because resistance movement happens very high. Therefore many forces should be spent for nothing. It turns out that easier (less expense of forces) carry cargo on back (in backpack).
The design of sledge has been simultaneously badly chosen and made. Absence of experience and preliminary careful designing of these sledge has yielded negative result.
If the design was more successful this sledge could very well it is useful at movement by the top part of ridge where there are no woods and snow is more dense.
A bit later so it has been made by some skilled groups of travellers on skis when they travelled on areas without wood. It, for example, Polar Ural Mountains and many areas of the Russian (or other) North. All these travellers in advance carefully developed designs and made the sledge at professional level. Then all did it on the basis of skis, and then (in 70th and 80th years) began apply entirely cast (or stamped) from plastic. However it was favourable apply them only in areas where there are no many woods.
As Kolevatov was at the very beginning period of application such sledge he has failed. It not its error, and absence of experience such use and absence of understanding as it is necessary do. In due course all would turn out, when there would be experience. But the misfortune with group has not given possibility to Alexander Kolevatovu continue these employment."
WAB may yet weigh in on this as his time allows. However, as he was well aware of the rules for category III certification at that time, I expect he would have mentioned if sledges such as this were not allowed.