With the Maintenance Support Walk-to-Work Vessel ‘KROONBORG’ a new standard is introduced to the offshore industry. Combining many functions enables ‘KROONBORG’ to support offshore activities to be more efficient, safe, comfortable and sustainable. ‘KROONBORG’ is the result of thorough research and design in tight co-operation between shipbuilder Royal Niestern Sander, shipping company Royal Wagenborg, end-user NAM/Shell UK and various suppliers.
Comfort was the point of departure for designing ‘KROONBORG’. Main dimensions and hull shape were tuned to the wave spectrum of the sailing area. The motion-compensated gangway (Ampelmann) and a revolutionary motion compensated Barge Master crane were key in the design of the vessel. The rest of the vessel was designed around these systems. The combination of the hull and the Voith Schneider propulsion system of this DP2 vessel results in optimal sea keeping behaviour, whereby employability of people, gangway and crane increased significantly. The bow thrusters, specially designed by Voith for DP applications, are the primary contributants to comfort and to fuel efficiency. Comfortable cabins, extremely low-noise innovative bow thrusters and modern facilities turn ‘KROONBORG’ into a pleasant working environment. The layout of the ship is fully adapted to the workflow of the gangway and crane. The integration of the chemical tanks was a technical challenge design wise, since regulations for different types of vessels were applied.
‘KROONBORG’ is an accommodation vessel, IMO 2 tanker, workboat and supply vessel rolled into one design. By combining unique functions, such as the cold start-up unit, integrated chemical tanks, workshop and storage facilities, offshore activities can be streamlined during a minimum of 300 days a year! The vessel contributes to substantial savings in maintenance costs of the unmanned platforms, for example, by reducing the number of helicopter flights. Also cranes and helidecks on the platforms are unnecessary.
“When the contract was signed, we did not have a solution or proven concept for either a crane, mobile cold start-up unit or the ability to transport type II chemicals on a platform supply vessel. 18 months down the road we introduced ‘kroonborg’. ”
Sustainability and environment
‘KROONBORG’ is the world’s first offshore vessel sailing on GTL (Gas To Liquid), a liquid fuel with substantially less emissions than conventional fuels. The fuel consumption figures during DP operations are very favourable due to the low power requirements of the Voith Schneider thrusters and Voith Inline thrusters. In addition, the autonomy of the vessel makes helicopters for deployment of offshore crews for the client NAM largely unnecessary, resulting in further substantial reduction in emissions and costs. The transport of specific chemicals in the integrated Duplex stainless steel tanks on board, coupled with the explosion-proof cargo pumping systems and the newly developed bunker hose reels contribute to environmental safety on the main deck. In addition, bunker procedures are easier and safer compared to the current situation, in which those substances are transported in tanktainers on deck.
Transferring people in wave heights up to 2.5 meters can be performed safely with a motion compensated gangway. Due to the high placement of the Ampelmann in combination with roll reduction, moving from this vessel to a platform is comfortable and safe. In addition, ‘KROONBORG’ features the world’s first Barge Master T40 fully motion compensated crane, which can transfer materials in a safe manner. Both systems are implemented with a high degree of redundancy. The restrictions and (im)possibilities of both functionalities played a central and important role in the vessel’s design. This is to ensure safety, efficiency and effectiveness. Enhanced security and flexibility is also achieved by the presence of a Daughter Craft (suitable for carrying fifteen people) developed by Palfinger Boats.
“In the 3 first months of operations she demonstrated that she does what she was designed to do in sea states up to 3,5m significant wave heights. This even happens to be 0,5m over and above design criteria assuring 90+% year-round operability!”
Experiences first 3 months of operations
- 3.000 persons transferred to platforms
- 1.000 lifts executed upto 4,5 tonnes
- 0 recoreded cases of motion sickness
- 250 TJ (6 mln m3) production restored
- 30% efficiency improvement over heli shuttling
- Crane reach demonstrated @32m LAT
- Operated all systems in Hs 3m seas
- Reduction CO2 footprint per passenger transferred