Commercial Rib Charter commission the build of the world’s first amphibious Crew Transfer Vessel

4 February 2022

Cowes, UK (04-02-22) – Commercial Rib Charter commission the build of the world’s first amphibious Crew Transfer Vessel for a six-year contract at RWE’s Scroby Sands wind farm off Great Yarmouth. In another first, ‘CRC Walrus’ is to be powered by Cox’s new 300HP diesel outboard engines.


RWE have been wrestling for several years with the difficulties of ever-changing sand banks restricting access to their Scroby Sands Wind farm. Aston Goddard of RWE challenged their specialist shallow draft CTV provider ‘Commercial Rib Charter’ to find an innovative solution. 


A textbook collaboration between RWE, RWE’s contract holder Commercial Rib Charter, naval architects Chartwell Marine and Isle of Wight based boat builders Diverse Marine has led to the design of the world’s first purpose built amphibious crew transfer vessel. The new boat is to be named ‘CRC Walrus’ in honour of R.J. Mitchells’ classic 1930’s Supermarine amphibious biplane.


‘CRC Walrus’ is a twelve-metre type approved crew transfer vessel with seating for two crew and eight passengers. There is a 750KG deck cargo capacity and the usual bow transfer system. Service speed is 23kts with a sprint speed of 29kts.


Powered by two Cox 300Hp diesel engines the vessel will draw only 80cm. The 600HP of motive power generated by the outboards will reduce fuel consumption by 50% over conventional inboard engines, thus further supporting RWE’s carbon neutral target.


‘CRC Walrus’ will transition from sea going to amphibious by lowering three hydraulically operated oversized wheels steered by a single nose wheel allowing her to ‘dock’ with the turbine ladder. The hydraulic system is powered by a generator.


Stuart Hedges of Commercial Rib Charter says ‘’The collaborative approach we have taken has helped mitigate the risk on such a technically innovative project. Working with highly competent marine architects and a boat builder steeped in experience has not only produced an excellent design but has done so to both budget and timetable. We signed the build contract with Diverse Marine in December, and we plan to be operational at Scroby in September this year.’’


Aston Goddard of RWE, who was himself a former CTV skipper on the windfarm is full of praise for the project. ‘’For many years we have trialled and tested various operational approaches to allow us to maintain continuous access to our turbines despite a rising seabed. Through the incredible support of both the internal RWE team and Commercial Rib Charter a bold and innovative vessel design has entered build which will deliver a step change in operational efficiency.’’ 


Ben Colman - Managing Director of Diverse Marine commented: “On behalf of the team at Diverse Marine and our UK supply chain I am delighted to have signed this contract with Stuart Hedges and Commercial RIB Charter. We have enjoyed a good relationship with Stuart and his operations team for over 5 years, supporting his existing CTV fleet and now adding CRC as a new construction partner. It is also great to be building this vessel for the Scroby Sands Offshore Wind Farm as we worked with the team there to build their last bespoke CTV ‘Eastern Aura’, now owned by CRC and named ‘CRC Vulcan’. Diverse Marine has a passion for the development of new technology that can be implemented in different market sectors and has a solid, proven track record of successfully delivering these projects in conjunction with many clients and supply chains. This 13m amphibious CTV is in good company and one we are super keen and grateful to be involved with. The team will take a very active role in configuring the vessel for its role at Scroby Sands.

 

Andy Page of Chartwell Marine commented: ”For Chartwell Marine this project represents another great opportunity to provide an innovative solution to a difficult challenge. We have been designing boats for offshore wind for over ten years now and as such have fond memories of running out the pier heads in Great Yarmouth to Scroby Sands. I think almost all the vessels that we have been involved in on the east coast have been tested there. RWE have always been very receptive to new ideas and have let us trial a number of concepts over the years including but not limited to novel bow fendering/ transfer solutions. This boat is a clear example of that, and represents a coming together of ingenuity and engineering capability between site manager, vessel operator, designer and builder. We are hugely grateful to Stuart and CRC for bringing us into the consortium and are looking forward to the build of the boat with the rest of the team.” 



3 October 2026
Diverse Marine is celebrating a significant milestone in its story, marking 50 vessels with a rather different viewpoint. From crew transfer vessels and lifeboats to daughter craft, specialist workboats and high-speed passenger vessels, the first 50 vessels represent the breadth of work undertaken by Diverse Marine and the expertise of the team behind them. Built in Cowes on the Isle of Wight, Diverse Marine vessels are now working across offshore energy, search and rescue, commercial marine and passenger operations around the world. Built by a team Every vessel begins with a different requirement. Some are designed to transfer technicians safely and efficiently to offshore wind farms. Others support search and rescue operations, carry passengers or undertake specialist work in demanding environments. Behind each one is the same combination of naval architecture, engineering, fabrication and craftsmanship, together with close collaboration between Diverse Marine, its clients, designers, suppliers and partners. Reaching 50 vessels is therefore about rather more than a number. It is a reflection of the people who have designed, built and delivered them. Celebrating a little differently To mark the milestone, Diverse Marine decided that the usual photograph at the shipyard gates was not quite enough. So, with FARRA ERIU providing the backdrop to the celebration, the team took to the water – and the skies – above the Isle of Wight.
11 June 2025
Southampton, 17th June 2025 — NR Marine Services is excited to announce that it has commissioned Chartwell Marine, a trusted pioneer of next-generation vessel design, to design a new CTV in response to client requests for a new class of vessel that is capable of supporting older generation assets, now referred to as legacy turbines, but utilising modern construction and outfit technology to maximise vessel fuel efficiency and technician comfort. It has been a generation since UK based Naval Architects and Shipyards designed a sub 22m, sub 60 tonne, sub 3m bow height crew transfer vessel. Chartwell Marine has developed the ‘Defiant Class”, a 20m CTV designed to Workboat Code Edition 3 with IMO Tier 3 compliance featuring a step free flush forward deck, resiliently mounted superstructure and modern furnishings and materials used in larger CTVs. This is a bold, DEFIANT step to do different, to create a new class of smaller CTV required for legacy turbines whilst not losing the core identity of modern UK designed, UK built and UK operated CTVs. DEFIANT in compliance, this new class of CTV will comply with Workboat Code Edition 3, IMO Tier 3 and the spirit and core fundamentals of HS_OSC – albeit in a more cost-effective approach. DEFIANT in pricing, it is essential the new class is cost effective in the modern market. UK quality but smartly sized to benefit from UK supply chain core strengths and therefore pricing. DEFIANT in reliability, working with supply chain to integrate a new, smaller Quad IPS IMO Tier 3 or Hamilton Waterjet propulsion solution with high power to weight ratio whilst maintaining simple, quality and reliable engineering. DEFIANT in change, accepting most legacy turbines have unique site requirements, the vessel retains flexibility to be tailored to different projects from a water jet propulsion system for shallow water sites and hybrid options where budgets allow to internal modularity to suit different racking and seating solutions. Andy Page of Chartwell Marine Ltd. said: “It is always enjoyable bringing a new class of vessel to the market. What’s interesting in this case, is the vessel is based-on “legacy vessel” parameters but with modern up-to-date experienced thinking. With the Defiant Class, we are able to utilise our proven high efficiency, high seakeeping performance hull form, in a smaller, more dynamic cost-effective platform, appropriate for the legacy turbine projects the vessels are intended to support”. Richard Thurlow of NR Marine Services Ltd. adds: “NR Marine Services is excited to be the first to bring the brand-new Chartwell DEFIANT Class CTV to the market. With strong industry focus being on the HSOSC market space, the CTV development has been taken away from the smaller vessel market. Working closely with Chartwell Marine and Diverse Marine we have looked at incorporating as many of the recent CTV developments a possible into a smaller package. Step free access from deck level to bow step over point, tiered seating, Male and Female heads, comprehensive galley suite and optimised hull design for near shore projects. Following an internal fleet review long with external market research, the data shows that there is a potential to replace older tonnage which is between 10-15 years old for near shore projects which have a lifespan that warrants investment in new CTV’s”. Ben Colman of Diverse Marine Ltd. adds: “Many years ago, the UK proved that building large numbers of smaller CTV’s was possible but these times have been forgotten as the CTV industry as evolved into larger. HS-OSC compliant craft. It is both exciting and challenging to be involved a project to build a new smaller CTV that meets the growing demand for legacy turbine access with modern technological compliance, modern materials, high fuel efficiency, hybrid options. Put simply the Defiant hosts, a modern, clean and spacious environment but on a smaller highly efficient platform that suits the smaller harbours, short transit sites and shallow water projects." ENDS Chartwell Marine is a trusted pioneer of next-generation vessel design. A reputed naval architect with an industry-leading track record designing award-winning high-speed vessels, Chartwell Marine supports ambitious boat builders and vessel operators around the world with specialist, independent design and consultancy services. To find out more, please visit: http://www.chartwellmarine.com/ About NR Marine Services: At NR Marine Services Ltd. we own and operate a fleet of seven vessels. Our services are available in the UK and throughout Europe. We pride ourselves on our offshore wind industry experience of more than 20 years’, including management of crew transfer vessels, turbine management in construction, commissioning and operational phases. Founded in 2019 and headquartered in Great Yarmouth our vessels are available for a wide range of duties. To find out more, please visit: https://www.nrmarine.co.uk
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