Seajacks’ latest vessel nears completion

Over the next few years, a steady stream of newbuilding WTIVs will appear on the market as owners and operators respond to the increase in demand from offshore wind projects as they move from the planning to construction stage. Seajacks, however, were early entrants in this respect, gaining valuable experience with the first two examples of this trio.

Lamprell Energy delivered Seajack’s first two WTIVs, Seajacks Krakenand Seajacks Leviathanin 2009, both now regular sights installing turbines at offshore windfarms in northern European waters. In June 2010 a contract was signed with Lamprell for a third vessel, to be named Seajacks Zaratanand now on schedule for delivery in May. The contract also provided Seajacks with an option for an additional vessel.

Like its predecessors, Seajacks Zaratancomes from the prestigious GustoMSC stable of offshore vessel designs. The first two were NG-2500X self-elevating platforms and Seajacks has selected a modified version of the larger NG-5500C design for the third vessel. Important decisions have to be made when selecting the various hull and propulsion variations on offer for these next generation WTIVs, and the Seajacks trio are based on jack-up, self-propelled, barge shaped hulls, this latest addition utilising a DP-2 propulsion system comprising three azimuthing thrusters aft and two retractable thrusters forward. The self-propelled option allows for autonomous transits, without the towage requirement of conventional non-propelled, jack-up barges which have provided sterling service with much of the turbine construction work currently underway. Seajacks says the vessel has been designed to satisfy the harsh environmental conditions of the North Sea, and while specifically aimed at the wind farm installation market, is also capable of serving the oil and gas industry.

The hull of Seajacks Zaratanis now reported as complete, with painting completed up to main deck level. Final welding of the four legs is now in progress with most of the work on the main deck now complete. The accommodation is structurally complete, with installation, electrical, plumbing and HVAC work continuing throughout. Machinery installation is also largely complete. The jacking system is now mechanically and hydraulically complete.

A major component with such vessels is the crane and at the time of the progress report, (late January) all main components of the 800 ton offshore crane were on site except for the main hoist wire. Remaining structural work is continuing, including installation of the main electrical power cables. The pedestals for the two auxiliary cranes are now complete, both of which are on site and are to be fitted after load out.

By Peter Barker