FOLLOWING almost two years of engineering, procurement and project preparations, Dutch heavy-lift specialist Dockwise has completed the first of two floatovers of semi-submersibles ultimately destined for the massive Shtokman project in the Russian sector of the Barents Sea.
The contract is worth some $100million to Dockwise and entails moving two 15,000-tonne semi-submersible hulls built at Russia’s Vyborg shipyard and two topsides that weigh approximately 19,000 tonnes each and which were constructed by Samsung in Korea.
Two Dockwise vessels were employed for phase one. Black Marlin loaded and transported the first of the two topsides to the floatover location at Geoje Island offshore South Korea for mating with a hull that was transported from Vyborg in northern Russia by the Talisman.
Preparing the hull for transportation was a complex task. It included the design and installation of a pre-lay anchor spread; tethering of the hull to this spread, and ballasting it to its mating draft.
This part involved the use of five tugs, two anchor-handlers, one workboat, two anchor barges, one test barge, a crane barge, three launch boats and guard boats.
After the hull had arrived off South Korea, it was floated off the Talisman, anchored and ballasted down prior to the Black Marlin precision docking with the unit and aligning the topsides with the hull prior to locking the leg mating units, transferring load, welding and so forth.
Once operations were completed, Black Marlin was “retracted”. The second topside and hull will be completed using the same process this autumn.
After that, both will be relocated halfway around the globe to Murmansk for final fitting-out. Once completed, the pair of drilling semi-submersibles are to be named Polyarnoye Zvezda (Polar Star) and Sevenoye Siyanie (Northern Light).