With demand for foundation installation vessels likely to grow as offshore wind goes global, and an established record in conversions such as Boskalis’ crane vessels Bokalift 1 and Bokalift 2, a leading naval architecture firm in The Netherlands has developed a new design
Vuyk Engineering’s analysis of the foundation installation vessel segment concurs with that of broker Clarksons Platou, which argued recently that the market could soon be under-supplied.
As Vuyk Engineering project manager vessel concepts Nicky Mayenburg told OWJ, apart from the overall size of the market, the rapid increase in wind turbine capacity and the size of foundations means larger installation vessels will be needed in the near future.
Based on its experience with projects such as Bokalift 1 and 2, and extensive consultation with vessel owners and operators, Vuyk Engineering believes the foundation installation vessel it had developed has a number of potential advantages.
“We believe we can make the process more efficient,” Mr Mayenburg told OWJ. “We reviewed the characteristics of the existing fleet of foundation installation vessels, and the vessels that are on order, and we think that our concept will be more efficient when it comes to the critical operations associated with foundation installation.
“We wanted to develop a crane vessel that was capable of cost-effective installation and decommissioning of offshore structures. The vessel was developed with the balance between initial investment, operational cost and workability as a key design driver.”
Mr Mayenburg explained that the main dimensions and vessel layout are optimized to meet the demands of the offshore wind and decommissioning industries. The deck layout is such that it can accommodate a significant number of structures. This is combined with an approach that aims at efficiency in the operational cycle, rather than pushing the upper limit of workability, to reduce cost.
At the heart of the design that Vuyk has developed is a vessel in which the need to handle foundations whilst they are on the deck of the vessel is minimised. This has resulted in a beamy vessel with a large clear deck and a mast-type crane that was selected because of its high lifting capacity and limited footprint on deck.
“We believe that simplicity is one of the keys to foundation installation,” said Mr Mayenburg. “Wherever possible, we have eliminated unnecessary movement of the foundations on the deck of the vessel.
“Another important characteristic of the design is that the crane can easily access all of the foundations on the deck without having to first move or reposition them in any way.
“As you would expect of a vessel that is designed to install foundations whilst in dynamic positioning (DP) mode, there is a motion-compensated pile gripper and handling system/upending tool.
“Operation of the pile gripper is integrated with the operation of the DP system, but no skidding or transfer system is required because of the dimensions of the deck, its breadth and the fact that the crane can reach all of the foundations.”
With a length overall of 185.0 m, Vuyk’s new design has a moulded breadth of 65.0 m, moulded depth of 13.0 m and a design draught of 8.0 m. It has a lifting capacity of 3,000-5,000 tonnes (depending on configuration), a deck area of 9,000 m2 and a deadweight of 40,000 tonnes.
The DP2 design has accommodation for 120 people, and optional helicopter deck and motion-compensated access system. The above-mentioned dimensions give it the ability to transport and install six extra-large monopiles of up to 12 m diameter. It can also transport a significant number of jacket-type foundations. The exact number depends on their size and type.
In keeping with most new vessel designs intended for the offshore wind energy industry, the Vuyk design also has a future-oriented power generation system based on diesel-electric machinery with engine exhaust treatment.
As an option, an environmentally-friendly fuel cell system can be added to create a hydrogen hybrid power generation system. The fuel cells, in combination with a battery pack, would supply a constant amount of sustainable energy to the vessel.