Abstract
The semi-submersible rigs can be transported to the place of working from the place of building by special ships. But some very big rigs or semi-submersible ships can be towed afloat, at the draft above upper deck of under-water pontoons. Growth of the distances between places of building and working of semi-submersible rigs means growth of the time and the expenses for their towing, and sufficient losses of drilling time. And, sometimes a more or less long travel between two places of working at drilling draft can be needed too. Some measures for towing resistance decreasing are recommended on the basis of model tests and comparable calculations. Now that the drilling places of rigs have moved to northern seas, it means more possible action of ice on the towed and/or standing rig. But today rig columns are not sufficiently intended for counteraction with ice. Some measurements for decreasing of towing resistance in ice are recommended too.
Published Version
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