Flensing is the removing of the blubber or outer integument of whales. English whalemen called it flenching, while American whalemen called it cutting-in.
In Spitsbergen, in the first half of the 17th Century, the processing of whales was primarily done ashore. Where the whale was flensed differed between the English and Dutch. The English brought the whale to the stern of the ship, where men in a boat cut strips of blubber from the whale's back. These were tied together and rowed ashore, where they were cut into smaller pieces to be boiled into oil in large copper kettles. The Dutch eschewed this system, bringing the whales into the shallows at high-tide and flensing them at low-tide. This latter method proved much less time-consuming and more effective. Both parties only cut off the blubber and the head, leaving the rest of the carcass to polar bears and sea birds.
In Japan the whole carcass was utilized. During the open-boat whaling era in Japan (1570s-1900s) whales were winched ashore by large capstans. There, men with flensing knives would not only cut up the blubber into long strips with the assistance of these capstans, but also cut up the viscera and bones to make various products.
Shore whaling flensing methods elsewhere differed little from the European whaling mentioned above. In California during the 19th Century whales could be winched ashore either at a sandy beach or, in the case of the Carmel Bay station just south of Monterey, they were brought to the side of a stone-laid quay to be flensed. Cutting-tackles were suspended from an elevated beam, allowing the whalemen to roll the carcass over in the water for flensing similar to a whaleship. On Norfolk Island humpback whales were flensed in the shallows along a rocky beach. Men sliced the blubber from the lean with the assistance of a winch.