It is interesting that shipwrights built kochs by intuition, with no drawings, on their vast experience only. Outline sketch of a future boat was drawn with a stick on sand. Close attention was paid to the bottom, because it experienced enormous loads, in particular when there was a need to drag the boat. 

Koch was equipped with two big anchors 4,5 poods (1 pood = 2 stones) each, and several two-pood anchors. They were used not only at sea but also for pulling the boat through the icefields. A reliably ‘sewed together’ boat withstood ice impact perfectly, was maneuverable, ruggedized, and light at the same time. In an unprecedented way, one day a koch was literally dragged over the Urals in the region of Yamal Peninsula. 

Famous seafarer Willem Barentsz, ice-bound on his state-of-th-art boat, wrote in his diary: ‘Today two Russian kochs going upstream passed by us. How do they manage to sail on these walnut-shells? ’ And he put his finger right on the crux. The silhouette of rounded and flattened bottom of a koch resembles just a nut-shell half.  

Thanks to this shape the koch hull did not break under the ice compression but was squeezed out to the surface. The Pomor experience was adopted by Norwegian shipbuilder Colin Archer, when he created his ship Fram whereon Rual Amundsen landed in Antarctic and reached the South Pole in 1911. This experience came in handy to Vice-Admiral Makarov for designing Yermak, the world’s first Arctic-class icebreaker. 

The Pomor kochs had excellent seaworthiness characteristics. They made 150-200 kilometers a day, and that significantly exceeded the capabilities of British merchant vessels and Dutch frigates; kochs navigated close to the shore in shallow-water channels inaccessible to deep-draft boats, and could enter river mouths.