Lloyd's List, 05.02.2008

Welcome debut for Combi Dock 1

New generation vessel offers advantages over conventional lift-on lift-off ships

FOLLOWING its delivery at the beginning of this year from Lloyd Werft in Bremerhaven, the first of a new generation of dockships is now on its maiden voyage. Combi Dock 1 will load two reactors at Marina di Carrara in Italy with each of the two 1,000 tonne pressure vessels rolled aboard over the 700-tonne capacity stern ramp.

The ship will then proceed to Aden where it will load two hopper split dredging barges, each weighing 400 tonnes, with its own cranes while a 1,200 tonne dredger will be floated on board. This dredging equipment will be discharged in Durban, then the vessel will proceed to Houston for discharging the two reactors.

Owners of the newbuild are Dockship 1 ApS, a wholly owned subsidiary of Combi Dock, itself a joint venture between Harp Shipping & Chartering of Bremen and J Poulsen Shipping of Korsoer.

The vessel will exclusively be managed by K/S Combi Lift, established in 2000 as a joint venture between J Poulsen Shipping and Harren & Partner, who will operate this ship and its three sister vessels in conjunction with its existing heavylift fleet.

Combi lift operates a fleet of nine modern multi-purpose heavylift vessels, ranging from 7,820 dwt to 5,100 dwt, fitted with deck cranes covering 2 x 250 to 2 x 610 tonnes lift capacity and built between 1996 and 2004.

The dockship concept is not new. Van der Laan employed this system in the 1970s, while Dockwise operates three dock-type vessels. However, these are relatively old and inherited from the earlier DockExpress concept, while one is an ex-Smit vessel which the Dutch towage specialist considered surplus to core activity.

Harren & Partners also has experience of operating dockships, having taken over the activities of Condock which operates two 4,500 dwt floodable hold 1984-built vessels.

Dock-type ships have some advantages over a conventional lift-on, lift-off configuration in that it provides ro-ro capability with good stability and a high deadweight-ballast ratio. The layout also overcomes the requirement for transverse bulkheads in the cargo space, allowing a virtual full length hold.

These advantages can be offset by a lower cubic capacity, 22,800 cu m in the case of the Combi Lift newbuildings, due to the loss of hold space under the main deck which is essentially the lower deck level. So gross tonnage at 17,200 dwt is higher than for a conventional multi-purpose heavylift carrier.

Comparing a similarly sized multi-purpose carrier in terms of loa and beam fitted with cranes of approximately the same rating, this latter vessel has a deadweight of approximately 20,000 dwt while the Combi Lift newbuildings will be rated at 11,000 dwt at a 6.6 m draught and 7,600 dwt when operating in ro-ro mode.

However, the company considers that for its targeted market sector a dock-type ro-ro vessel with high capacity deck cranes offers a unique flexibility which far outweighs any disadvantages of this type of design.

The Combi Lift ships, ordered from Lloyd Werft at a cost of €100m ($149m) for delivery in January and June, are the first dock-type ships to be built for a decade and the result of a market investigation by the operator which identified a need to transport floating plus ro-ro cargo as well as lifting non-floating units by high capacity deck cranes.

Accordingly, the 11,000 dwt design is provided with a single floodable hold measuring 132 m by 18 m sealed by a stern ramp reinforced to take ro-ro loads up to 700 tonnes.

Clear height in the hold is 9.4 m while the 20 pontoon-type tweendeck covers can subdivide the hold at a height of either 6 m or 4.7 m. A tweendeck pontoon cover can also be employed to sub-divide the hold vertically into two compartments at three positions.

With the main hold flooded, the vessel can accept floating cargo with a maximum draught of 4.5 m and when emptied the main deck is strengthened to withstand a loading of 16 t/sq m. The centreline docking blocks can support a 150 tonne load while the side docking blocks are strengthened for a 90 tonne loading. Also, each 20 ft deck frame is strengthened to 350 tonnes, increased to 490 tonnes for the 40 ft frames.

The Combi Lift newbuildings will be equipped with two Liebherr deck cranes mounted on the starboard side forward, each capable of an individual lift of 350 tonnes at 18 m outreach and 200 tonnes at 31 m radius – together providing a maximum twinned lift of 700 tonnes. These are supplemented by a single Liebherr crane fitted on the port side rated at 200 tonnes at 14 m outreach and 75 tonnes at a 31 m radius. The ships will be prepared for dynamic position DP01, able to maintain the vessel in position up to Beaufort 6 sea states.

Two joystick control stands will be fitted, one adjacent to the main conning position and the other aft of the bridge overlooking the working deck, although to obtain the DP01 notation it may be necessary to augment the 700kW tunnel type bow thruster.

Additionally, to assist in offshore work, provision has been made for a 6 m square moon pool located 73.4 m aft.

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