Vos Partner, photo by Lucien van der Horn.

Energy Partner

Energy Partner (first name: Vos Partner)A platform supply vessel of the PX121 design, which has a competitive combination of fuel-efficiency and cargo capacities/deadweight. This translates to a performance level that is usually expected from larger PSVs, but at a medium-sized PSV cost - delivering excellent value-for-money for the owner and operator.

Owned By
Vroon Offshore Services
Built By
Partner yard
IMO Number
Operated By
VOS Genoa

Primary Specifications

83.4 m
18 m
Dead weight
4200 tonnes
Speed (max)
15 kn
23 POB
Deck area
830 sqm
Note: Specifications may have changed since the original completion date.
  • VOS Partner, Ulstein ship design number 100.
  • VOS Partner, a PX121 platform supply design featuring the X-BOW hull line design. Photo is taken at the Cosco Guangdong Shipyard.
  • VOS Partner, an Ulstein design of the PX121 type, is owned and operated by Vroon Offshore Services.

Ship history

'VOS Partner' is design number 100 from Ulstein Design & Solutions AS. 'VOS Partner' is the third in a series of six PX121-type PSVs that feature the Ulstein-patented X-BOW design and were built for Vroon at Cosco Guangdong Shipyard in China. These vessels offer a competitive combination of excellent fuel efficiency and impressive cargo capacity, backed up by a high level of performance and on-board comfort for both clients and crews.

In March 2013, the Dutch ship owner Vroon Offshore Services contracted two PX121 designed platform supply vessels for construction at the Chinese COSCO Guangdong Shipyard. October saw the declaration of two options, pushing the total number of sold designs from Ulstein past the #100 mark. In July 2014, a further two options were declared. The vessels are delivered during 2015 - 2017.

ULSTEIN delivered ship design, power & control equipment and on-site follow-up services for all six vessels.

Thanks to flexible tank capacities, the PX121 is set up to support drilling activities with longer and deeper boreholes and activities further from shore. In addition to tanks for oil, water and drilling fluids, the vessel also has two stainless steel tanks for flammable liquids or corrosive chemicals. Each ship will be equipped with dynamic positioning system Class II and meets the requirements of 'Clean Design', according to ABS class.

The X-BOW offers efficiency over a wide draught range, which is important for PSVs as they often operate with varying loads. Furthermore, the X-BOW has unique, advantageous qualities in terms of motion and propulsion efficiency in moderate and heavy seas. Its innovative shape eliminates wave slamming and bow impact delivering better performance, while reducing noise and vibration, which in turn translates to enhanced crew comfort and safety levels.

Overview vessels:

  • VOS Pace - delivered on 6 February 2015 - IMO number 9685750
  • VOS Paradise - delivered on 4 August 2015 - IMO number 9685762
  • VOS Partner - delivered on 14 January 2016 - IMO number 9709128
  • VOS Passion - delivered 23 August 2016 - IMO number 9709130
  • VOS Patience - delivery July 2017 - IMO number 9742089
  • VOS Patriot - delivered on 22 March 2018 - IMO number 9742091

Operational work:

29 November 2017: Vroon announced that VOS Partner, and VOS Patience, recently had started a charter for oilfield services company TechnipFMC. The two PSVs were delivered in Malta and will support TechnipFMC, supplying pipelines and subsea materials to TechnipFMC's construction assets offshore in the Mediterranean. Both units will operate in the Mediterranean for two, non-consecutive phases in 2017 and 2018. Both vessels are under commercial and operational management by VOS Genoa.

2023: Golden Energy Offshore Services AS has entered into an agreement on acquiring four of these vessels, the VOS Pace, VOS Partner, VOS Passion and VOS Paradise, an acquisition that will be completed by September 2023.