Ferry conversion to offshore accommodation begins

The ships, built at the Remontowa yard in Gdansk, Poland in 2007 and 2008 began life as the passenger ferries Siluna Ace and Simara Ace on the short crossing of the Öresund strait between Denmark and Sweden, but were rendered surplus to requirements after the fixed link gained popularity.

Dutch company Chevalier Floatels’ ethos is to provide vessels that are more than just ‘floating accommodations’; the company says it likes to concentrate on the wellbeing and comfort of the staff on board. Additionally, environmental responsibility and low operating costs are high priorities. However, there is also much focus on reducing operating costs (including fuel), environmental/social aspects and of course reliability. In keeping with these aims, a comprehensive upgrade and modification programme has been formulated, and Holland Shipyards was commissioned to convert the first vessel, which will be renamed DP Gezina.

DP Gezina will have Lloyd’s Class approval, according to the SPS Code, and will operate as a DP2 Service Support Vessel. To ensure that the owner’s high standards are met, the company says it involved superyacht and interior specialists alongside offshore experts, hoping to guarantee a high level of reliability, efficiency and comfort.

Being originally designed as a passenger vessel, the hull exhibits a smooth ride and good seakeeping characteristics, and various steps are being taken to ensure that this is maintained. Cabin accommodation is being built to yacht standards, with levels of equipment to match, while the public areas will include fitness rooms and common recreational rooms set for 24-hour service. As converted, the ship will accommodate up to 60 personnel in single cabins, but the conversion is being carried out so that half of the accommodation can be rearranged as twin-berth cabins, holding 90 people.

Water makers, waste water system, solid waste system, food storage units and fuel tanks are to be provided so as to give the vessel 30-day autonomy. Navigation and bridge equipment, with integrated automation and monitoring systems, will be upgraded to ensure safety and reliability.

The diesel-electric propulsion plant will be upgraded to provide DP2 capability, with two 360° azimuthing thrusters aft and two bow thrusters – one a retractable 360° thruster and the other fixed. A power management system will ensure that the diesel gensets run at optimum load, keeping both fuel consumption and exhaust emissions relatively low.

For transferring workers to wind turbine or platform installations, the ship will be fitted with a self-stabilising Ampelmann personnel transfer system, which actively compensates for vessel motion. This walkway is being placed so that entrance platforms of windmills, or working decks of a platform, can be accessed straight from the accommodation vessel, avoiding the need for dangerous transfers close to the water and waves.

Transfers between the accommodation ship and the workplace will be further facilitated by the DP2 system and retractable stabilisers, designed to allow safe transfers in seas of up to 3m significant wave height. This, says Chevalier Floatel, represents availability of 85% to 90%. The ship is to be fitted with platforms on each side and at the stern to allow other vessels to come alongside.

The conversion will give the DP Gezina a degree of multi-purpose capability, thanks to other additions such as a multi-beam sonar enabling it to perform bottom surveys and inspections of foundations of offshore structures. These additional capabilities should, according to Chevalier, offer a wide range of employability, with little or no idle time.

Although the conversion is being carried out primarily for work in connection with wind farms, the design allows simple adaptation to make the DP Gezina suitable for personnel accommodation and transport duties in the wider offshore oil and gas exploration and exploitation market should the need arise.

The DP Gezina is scheduled to re-enter service in its new role by the end of April 2013, when it will available as a staff accommodation and transport vessel for offshore maintenance and installation projects in the wind, oil and gas industry.

Principal particulars DP Gezina:

Length oa: 69.4m
Length bp: 60.2m
Breadth waterline: 11.4m
Breadth max: 13.4m
Draught: 3.1m
Capacity: 60 to 90 personnel
Class: Lloyd’s X.100 A X. LMC, UMS, DP (AA) Service Support Vessel SPS-code 2008