An SOV vessel converted from a PX121 platform supply vessel.

PSV conversion - moving to a new lease of life as SOV or IMR vessel

We have developed new-life solutions for our series of medium-sized PX121 PSVs, capitalising on the inherent strength of the vessel’s solid platform. One option is the conversion into an SOV vessel for the offshore wind or oil & gas markets. Another option is the conversion into a flexible subsea IMR vessel.

This is the time to consider repositioning existing PSV vessels to a new life in a new market segment with an attractive cost base and a short conversion time.

The renewables market is bustling, and there is a constant need for turbine inspection, maintenance, and repair, as well as support for installation and commissioning activities during the construction phase. In the offshore Oil and Gas markets, walk-to-work operations represent a promising alternative for carrying out Operation and Maintenance activities at unmanned platforms.

A well-thought-through conversion of the vessel can mean a new lease of life, as the vessel can compete for short/medium-term contracts where a new build cannot be carried out.

Ulstein has taken the initiative to develop new-life solutions for our series of medium-sized PX121 Platform Supply Vessels, capitalising on the inherent strength of the vessel’s solid platform.

One option is to convert it into an SOV, a Service Operations Vessel, with walk-to-work functionality for the offshore wind or oil and gas market.

Another option is converting into a flexible subsea IMR (inspection, maintenance, repair) vessel.

The ULSTEIN PX121 provides a remarkably suitable platform for a conversion, as the vessels have favourable motion characteristics and good seakeeping and station-keeping performance.
This reduces the scope of a conversion and improves the workability of the final solution.

Due to Ulstein’s extensive experience with newbuild Subsea IMR and Walk-to-Work SOVs, all the knowledge and tools are available to guide an owner towards the conversion that best suits its business case.

Conversion to SOV

The PX121 vessel can be converted into an SOV vessel by upgrading the accommodation to 90 and installing a walk-to-work gangway with adjustable pedestal and integrated elevator, a work boat, and lifeboats. The upgrade includes storage capacity for containers and workshops, and much attention has been given to achieving an efficient workflow in the onboard logistics.

Conversion to IMR

The PX121 vessel can be converted into an IMR vessel by installing extra accommodation, an offshore crane (we recommend a 60t AHC), and, optionally, lifeboats. With these additions, the vessel will have a 700 sqm work deck, which opens up the possibility of performing multiple IMR assignments worldwide.

The conversion can be done at Ulstein Verft or a yard of your choice, with Ulstein providing the design, engineering, and equipment.

  • Converted PX121 PSV vessel to SOV vessel
    After conversion to an SOV vessel.
  • Converted PX121 PSV vessel to IMR vessel
    After conversion to an IMR vessel.

PX121 DESIGN SPESIFICS

The development of the ULSTEIN PX121 platform supply vessel design has been to present a vessel with capacities and performance close to the larger PSV segment while still at a cost that will provide excellent value-for-money to the owner/operator. The vessel is designed for environmentally friendly operations worldwide.

Some of these vessels are in lay-up due to the market situation. With a conversion, they can move into a new lease of life.

Flexibility

The PX121 was developed with efficiency and flexibility in mind. It is equipped with a dynamic positioning system Class II and meets the requirements of DNV's Clean Design. The ship is also equipped with catalysts for all four main engines.

Accommodation quality

The accommodation is of high quality. Floating floor on all accommodation decks provides low noise and vibration levels.

Main dimensions

Length over all approx. 88.9 m
Length between p.p. 82.1 m
Breadth moulded 18.0 m
Depth to main deck 8.0 m
Max. draught 6.6 m
Design draught 6.0 m 
Accommodation 30 p.

Get in touch

DSC4827 comp bw

Roy Lindset

Description
Manager service dept.
Affiliation
Ulstein Design & Solutions AS

Latest news

2025 Ganway connections
Feature

Mastering walk-to-work operations

The total number of walk-to-work (w2w) vessel designs and redesigns by Ulstein now count 22, of which 14 are currently in operation. In average, these vessels perform repair and maintenance on more than 5,000 turbines – every year! 
That makes a stunning 95,000+ gangway connections!

The heavy lift pipelay vessel, ‘JSD 6000’, is a customised ULSTEIN SOC5000 design. The 215m long DP3 vessel is equipped with a 5,000t revolving main crane and will be cable of performing J-lay and S-lay pipelay work in max water depths of 3,000m.. The combination of heavy lift and S-Lay capabilities together with J-Lay functionality via a large, off-centre moonpool, allows the vessel to serve deepwater and SURF markets as well as shallow-water EPCI projects.  The JSD 6000 vessel is the third cus
Press Release

Totally three Ulstein ship designs win Work Boat World Awards for 2024

Three of Ulstein's designs are among the Work Boat World Awards 2024 winners. Tamhae 3 clinched the 'Best Large Research Vessel' award, Olympic Boreas was named 'Best CSOV', and JSD 6000 took home the 'Best Derrick Layer' accolade from Baird Maritime/Work Boat World. These awards celebrate the best vessels in their categories, judged on design, build quality, and functionality.

DSC4827 comp bw

Roy Lindset

Manager service dept.

Affiliation
Ulstein Design & Solutions AS