Given the question: Given the following context: Returning to Danes Island in the summer of 1897, the expedition found that the balloon hangar built the year before had weathered the winter storms well. The winds were more favorable, too. Andree had strengthened his leadership by replacing the older and critical Ekholm, an authority in his field, with the 27-year-old enthusiast Knut Frnkel.On 11 July, in a steady wind from the south-west, the top of the plank hangar was dismantled, the three explorers climbed into the already heavy basket, and Andree dictated one last-minute telegram to King Oscar and another to the paper Aftonbladet, holder of press rights to the expedition. The large support team cut away the last ropes holding the balloon and it rose slowly. Moving out low over the water, it was pulled so far down by the friction of the several-hundred-meter-long drag ropes against the ground as to dip the basket into the water. The friction also twisted the ropes around, detaching them from their screw holds. These holds were a new safety feature that Andree had reluctantly been persuaded to add, whereby ropes that got caught on the ground could be more easily dropped. Most of them unscrewed at once and 530 kilograms (1,170 lb) of rope were lost, while the three explorers could simultaneously be seen to dump 210 kilograms (460 lb) of sand overboard to get the basket clear of the water. Seven hundred and forty kilograms (1,630 lb) of essential weight was thus lost in the first few minutes. Before it was well clear of the launch site, the Eagle had turned from a supposedly steerable craft into an ordinary hydrogen balloon with a few ropes hanging from it, at the mercy of the wind; its crew had no means to direct it to any particular goal and had too little ballast for stability. Lightened, the balloon rose to 700 metres (2,300 ft), an unimagined height, where the lower air pressure made the hydrogen escape all the faster through the eight million little holes. The balloon had two means of communication with the outside world, buoys and homing pigeons.... answer the following question: Most of what was unscrewed at once?
The answer is:
screw holds